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Cited by 233Barrier Structure and Function StudiesPluripotent Stem Cells ResearchThyroid Disorders and Treatments

Modeling Psychomotor Retardation using iPSCs from MCT8-Deficient Patients Indicates a Prominent Role for the Blood-Brain Barrier

Open access
Vatine, Gad D., Al-Ahmad, Abraham, Barriga, Bianca K., Svendsen, Soshana, Salim, Ariel, Garcia, Leslie, Garcia, Veronica J., Ho, Ritchie +12 more·2017·Cell Stem Cell
DOI 10.1016/j.stem.2017.04.002PMC PMC6659720
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Abstract

SUMMARY Inactivating mutations in the thyroid hormone (TH) transporter Monocarboxylate transporter 8 (MCT8) cause severe psychomotor retardation in children. Animal models do not reflect the biology of the human disease. Using patient-specific induced pluripotent stem cells (iPSCs), we generated MCT8- deficient neural cells that showed normal TH-dependent neuronal properties and maturation. However, the blood-brain barrier (BBB) controls TH entry into the brain, and reduced TH availability to neural cells could instead underlie the diseased phenotype. To test potential BBB involvement, we generated an iPSC-based BBB model of MCT8 deficiency, and we found that MCT8 was necessary for polarized influx of the active form of TH across the BBB. We also found that a candidate drug did not appreciably cross the mutant BBB. Our results therefore clarify the underlying physiological basis of this disorder, and they suggest that circumventing the diseased BBB to deliver active TH to the brain could be a viable therapeutic strategy.

AI snapshot

Written from the paper’s full text.

TL;DR

Using patient-derived iPSCs, MCT8-deficient neural cells showed reduced thyroid hormone transport but retained normal T3-dependent neuronal maturation, whereas MCT8-deficient blood-brain barrier endothelial cells lost polarized T3 transport. The findings suggest that defective MCT8-mediated T3 entry across the human BBB, rather than neural MCT8 deficiency alone, drives the neurological phenotype of Allan-Herndon-Dudley syndrome.

Key findings

  • MCT8-deficient iPSC-derived neural cells had a 5-fold decrease in T3 uptake and efflux (p < 0.005 and p < 0.05), and a 3-fold decrease in T4 uptake and 4-fold decrease in T4 efflux (p < 0.0001 and p < 0.0002), yet showed normal T3-induced KLF9/HR transcription, differentiation, proliferation, apoptosis, and T3-dependent neuronal maturation; T3 increased spontaneous activity in control and MCT8-deficient neurons (p < 0.038 and p < 0.014).
  • iPSC-derived brain microvascular endothelial cells (iBMECs) from controls and MCT8-deficient patients formed tight barriers with average TEER ~1,500 Ω × cm² and similar BBB transporter expression; MCT8-deficient iBMECs showed significantly reduced T3 and T4 uptake (p < 0.0001), significantly decreased T3 permeability (p < 0.0001), and completely abolished net trans-iBMEC T3 permeability (p < 0.0001), while T4 transport was not significantly affected.
  • LC-MS/MS confirmed lower T3 transport in MCT8-deficient lines, restored T3 transport in the CRISPR-corrected isogenic line, and deficient T3 transport in the MCT8-mutated control line; MCT8 mediated polarized blood-to-brain T3 influx (p < 0.0001).
  • The candidate drug DITPA crossed control and MCT8-deficient iBMECs with very low permeability, more than 100-fold lower than T3, in an MCT8-independent manner.

Methods

  • Fibroblasts from two severely affected male MCT8-deficient patients and controls were reprogrammed into iPSCs; CRISPR/Cas9 was used to generate isogenic MCT8-mutated and corrected lines.
  • iPSCs were differentiated into EZ-sphere neural cultures and iBMECs; assays included radiolabeled T3/T4 uptake and efflux, Transwell permeability and TEER, multi-electrode array recording, RNA-seq, qRT-PCR, Western blot, immunocytochemistry/immunohistochemistry, and LC-MS/MS for T3, T4, and DITPA.
  • Statistical analysis used unpaired Student’s t tests, nested ANOVA with Tukey correction for multiple comparisons, and a two-sided p < 0.05 significance threshold; experiments were performed in duplicates or triplicates with at least three independent neural or iBMEC differentiations.

Limitations

  • The paper states that in vitro cell models exposed to relatively high T3 concentrations (0.1–100 nM) do not fully recapitulate in vivo conditions with lower picomolar free thyroid hormone levels in the bloodstream.
  • The paper notes that the lack of neurological improvement with DITPA may also be due to late treatment initiation in patients (ages 9–21 months), and that development of the MS approach is ongoing to test additional analogs.
  • Evident from the text: the study used two MCT8-deficient patient lines and a single clone per cell line, and the conclusions rely on iPSC-derived in vitro BBB and neural models without in vivo human validation.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.stem.2017.04.002

Cites

56 of 56 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

23 of 40 cited sources checked · 18 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    When Mct8 KO mice were made hypothyroid at neonatal stage, exogenous supplementation of T4, but not T3, rescued a mild phenotype in the cerebellum.

    “When these mice were made hypothyroid at the neonatal stage, the exogenous supplementation of T4, but not T3, was able to rescue a mild phenotype in the cerebellum (Ceballos et al., 2009).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Ceballos et al., 2009 source
  • Premisecitation

    Murine Mct8 regulates the transport of T3 across the BBB.

    “Murine Mct8 regulates the transport of T3 across the BBB (Ceballos et al., 2009; Mayerl et al., 2014)”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites Ceballos et al., 2009 source
    • cites Mayerl et al., 2014 source
  • Premisecitation

    MCT8-deficient patient fibroblasts and human cell lines do not harbor the characteristics of affected neural or endothelial cells required for a relevant human cell-based disease model of AHDS.

    “While these cell models showed some features of MCT8 deficiency, they do not harbor the characteristics of affected neural or endothelial cells that are required for a relevant human cell-based disease model of AHDS.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Visser et al., 2009 source
    • cites Visser et al., 2010 source

      The Discussion (page not provided) cautions that abnormalities found in patients’ peripheral cells may not reflect abnormalities in the brain, supporting a limitation of fibroblast models. But the paper does not establish that the fibroblasts or human cell lines lack the required characteristics of affected neural or endothelial cells; it instead describes its fibroblast–brain transcriptome comparison as informative for understanding the disease. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Premisecitation

    The one published post-mortem analysis of a MCT8-deficient fetus revealed a decrease in T3 and T4 contents in the cerebral cortex.

    “The one published post-mortem analysis of a MCT8-deficient fetus revealed a decrease in T3 and T4 contents in the cerebral cortex (López-Espíndola et al., 2014)”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites López-Espíndola et al., 2014 source
  • Findingcitation

    DITPA had a lower iBMEC permeability than that reported for BBB-impermeant sucrose using the same iBMEC model.

    “Moreover, DITPA had a lower iBMEC permeability than that reported for BBB-impermeant sucrose using the same iBMEC model (Lippmann et al., 2012).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Lippmann et al., 2012 source
  • May combine two claims. 42
  • Classified as probably not a substantial claim. 23

  • May combine two claims.

    Premisecitation

    SLC16A2 encodes MCT8, a specific membrane transporter of TH, broadly expressed in the CNS.

    “The solute carrier family 16, member 2 (SLC16A2) gene, located on the X chromosome, encodes monocarboxylate transporter 8 (MCT8), a specific membrane transporter of thyroid hormone (TH) (Friesema et al., 2003) broadly expressed in the central nervous system (CNS).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Friesema et al., 2003 source

  • May combine two claims.

    Findingcitation

    RNA-seq data for MCT8 gene expression in human brain demonstrated similar levels in purified human endothelial cells, astrocytes, and neurons, and to a lesser extent in mature oligodendrocytes, and it was not detected in microglia.

    “Analyzing RNA-seq data for MCT8 gene expression in the human brain (Zhang et al., 2016) demonstrated similar levels in purified human endothelial cells, astrocytes, and neurons, and to a lesser extent in mature oligodendrocytes, and it was not detected in microglia (Figure 3A).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Zhang et al., 2016 source

  • May combine two claims.

    Premisecitation

    Two Mct8 KO mouse strains closely recapitulate the thyroid phenotype, but fail to display neurological or behavioral abnormalities.

    “two Mct8 knockout (KO) mouse strains closely recapitulate the thyroid phenotype, but they fail to display neurological or behavioral abnormalities (Dumitrescu et al., 2006; Trajkovic et al., 2007).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Dumitrescu et al., 2006 source
    • cites Trajkovic et al., 2007 source

      The Figure 8 discussion says this paper’s mouse model replicates the abnormal thyroid-hormone phenotype and lacks overt neurological deficits. The phenotypical analysis also reports no overt motor deficits or ataxia. The paper describes its own model, not both strains cited in the sentence, and reports subtle CNS changes; it therefore does not establish an unqualified absence of neurological abnormalities. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S2 (checkable).

    Premisecitation

    iPSCs provide an unprecedented platform for studying human genetic disorders.

    “Technologies to reprogram adult cells back to a pluripotent state, termed induced pluripotent stem cells (iPSCs) (Takahashi and Yamanaka, 2006; Yu et al., 2007), provide an unprecedented platform for studying human genetic disorders (Ebert et al., 2009; Mattis et al., 2015).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Takahashi and Yamanaka, 2006 source
    • cites Yu et al., 2007

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Ebert et al., 2009 source

  • May combine two claims.

    Premisecitation

    T4, but not T3, may cross the mouse MCT8-deficient BBB through a mouse-specific T4 transporter that is absent in human.

    “This suggests that T4, but not T3, may cross the mouse MCT8-deficient blood-brain barrier (BBB) through the presence of a mouse-specific T4 transporter that is absent in human.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Ceballos et al., 2009 source

  • May combine two claims.

    Premisecitation

    Mct8/Oatp1c1 double KO displayed a severe form of CNS-specific hypothyroidism, including decreased myelination and abnormal neuronal differentiation.

    “the Mct8/Oatp1c1 double KO displayed a severe form of CNS-specific hypothyroidism, including decreased myelination and abnormal neuronal differentiation (Mayerl et al., 2014).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mayerl et al., 2014 source

  • May combine two claims.

    Interpretationcitation

    Human iBMECs express LAT1, LAT2, and MCT10, which may transport T4.

    “human iBMECs do express LAT1, LAT2, and MCT10, which may transport T4 (Zevenbergen et al., 2015).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Zevenbergen et al., 2015 source

      The Results report T4 uptake by LAT1 in transfected COS1 cells, while the Discussion describes LAT2 as a poor T4 transporter. The paper does not establish LAT1, LAT2, or MCT10 expression in human iBMECs, and it does not assess T4 transport by MCT10. Thus it supports the possibility of T4 transport by LAT1, but not the full statement attributed to it. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    The iBMEC model possesses many BBB-relevant properties, including physiologically relevant TEER values and efflux transporter activity, and expresses a comparable set of BBB genes to those expressed in cultured primary human BMECs and BMECs purified from human brain tissue.

    “The model possesses many BBB-relevant properties (Lippmann et al., 2012), including physiologically relevant TEER values and efflux transporter activity, and expresses a comparable set of BBB genes (TJ proteins, ATP-binding cassette [ABC], SLC transporters, etc.) to those expressed in cultured primary human BMECs and to BMECs purified from human brain tissue.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Lippmann et al., 2012 source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Chromosomal abnormalities can occur during the reprograming process and over time during cell passaging.

    “Chromosomal abnormalities can occur during the reprograming process and overtime during cell passaging (Hamada et al., 2012).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Hamada et al., 2012 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    DITPA is a TH analog that can activate the T3 signaling cascade and has been tested in animal models and MCT8-deficient patients.

    “As an example, DITPA is a TH analog that can activate the T3 signaling cascade and has been tested in animal models and MCT8-deficient patients (Ferrara et al., 2015; Verge et al., 2012).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Ferrara et al., 2015 source
    • cites Verge et al., 2012 source

  • May combine two claims.

    Findingown data

    Immunofluorescence determined that MCT8 was co-localized with BBB Glucose transporter 1 (GLUT1) and expressed in Purkinje cells.

    “immunofluorescence determined that MCT8 was co-localized with the BBB Glucose transporter 1 (GLUT1) and expressed in Purkinje cells (Figure 3C).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In addition to MCT8, iBMECs expressed LAT2, MCT10, and high levels of LAT1, and these transporters were expressed uniformly in iBMECs derived from the various iPSC lines.

    “the expression profile of TH transporters showed that, in addition to MCT8, iBMECs expressed LAT2, MCT10, and high levels of LAT1, and that these transporters were expressed uniformly in iBMECs derived from the various iPSC lines (Figure 3G).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Ingenuity pathway analysis of differentially regulated genes revealed pathways regulated by T3 in human neural cells, some of which may correlate with neuronal maturation.

    “Ingenuity pathway analysis of the differentially regulated genes revealed pathways that are regulated by T3 in human neural cells (Figure S4B), some of which may correlate with neuronal maturation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Differentiated neural cells expressed DIO3, but not DIO1 and DIO2.

    “assessing iodothyronine deiodinase mRNA levels revealed that DIO3, but not DIO1 and DIO2, was expressed (Figure 1E)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Differentiated neural cells expressed MCT8 and other TH transporters LAT1 and LAT2, and low levels of OATP1C1, with similar levels in control and MCT8-deficient cells.

    “RNA sequencing (RNA-seq) analysis on differentiated neural cells revealed that these cells not only expressed MCT8 but also other TH transporters, LAT1 and LAT2, and low levels of OATP1C1 (Figure 1D), with similar levels in control and MCT8-deficient cells.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    iBMEC monolayers plated on Transwell formed functionally tight barriers to passive diffusion, with average TEER values of ~1,500 Ω × cm2, with no statistically significant differences in TEER among the lines.

    “Results showed tight monolayers, with average TEER values of ~1,500 Ω × cm2, with no statistically significant differences in TEER among the lines (Figure 4C).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Functional efflux was similar across control and MCT8-deficient iBMEC lines, correlating with indistinguishable transporter expression levels.

    “Increased accumulation in the presence of inhibitors showed that functional efflux was similar across the control and MCT8-deficient iBMECs lines, correlating with indistinguishable transporter expression levels (Figure S6C).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    EZ-spheres contained Nestin+ neural progenitor cells, which could be differentiated into neural cultures expressing βIII-Tubulin+ neurons and GFAP+ astrocytes that expressed MCT8.

    “EZ-spheres contained Nestin+ neural progenitor cells, which could be differentiated into neural cultures expressing βIII-Tubulin+ neurons and glial fibrillary acidic protein (GFAP)+ astrocytes that expressed MCT8 (Figure 1B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Western blot confirmed MCT8 expression in CS03iCTR control line, CS01iMCT8 line expressing mutated nonfunctional MCT8, and corrected isogenic line CS01iMCT8cor, but not in CS03iCTRmut line engineered to express truncated MCT8.

    “Western blot analysis confirmed MCT8 expression in the CS03iCTR control line as well as in the CS01iMCT8 line that expressed mutated, nonfunctional MCT8 protein and its corrected isogenic line (CS01iMCT8cor), but not in the CS03iCTRmut line that was engineered to express a truncated MCT8 protein (Figure 1C).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    iBMECs expressed DIO2 and higher levels of DIO3, but not DIO1.

    “iBMECs expressed DIO2 and higher levels of DIO3, but not DIO1 (Figure 3H).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Recorded bursts per minute were significantly increased by T3 in control cells (p < 0.01), and showed a trend in MCT8-deficient cells.

    “the recorded bursts per minute were also significantly increased by T3 in control cells (p < 0.01; Figure 2E), and they showed a trend in MCT8-deficient cells (Figure 2F).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    iBMECs derived from each iPSC line expressed BBB drug efflux transporters P-gp/ABCB1, BCRP/ABCG2, and MRP1/ABCC1, with similar expression levels between lines.

    “The iBMECs derived from each iPSC line expressed BBB drug efflux transporters P-glycoprotein (P-gp/ABCB1), breast cancer-resistant protein (BCRP/ABCG2), and multidrug resistance-associated protein 1 (MRP1/ABCC1) (Figure S6A), with similar expression levels between lines (Figure S6B).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The CS03iCTRmut isogenic line incorporated an 8-base pair deletion that caused a frameshift introducing an early stop codon and resulted in a truncated protein, mimicking the truncated non-functional MCT8 protein in the CS58iMCT8 iPSCs.

    “This isogenic line incorporated an 8-base pair (bp) deletion (Figures S2A and S2B), which caused a frameshift that introduced an early stop codon and thereby resulted in a truncated protein, mimicking the truncated non-functional MCT8 protein in the CS58iMCT8 iPSCs (Figure S2C).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Human iBMECs expressed LAT1, LAT2, MCT10, DIO3, and lower levels of DIO2, similar to purified human BMECs.

    “Human iBMECs expressed LAT1, LAT2, MCT10, DIO3, and lower levels of DIO2, similar to purified human BMECs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    T3 transport in the reverse direction was low and similar across all control and MCT8-deficient lines.

    “While T3 transport in the reverse direction was low and similar across all control and MCT8-deficient lines”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The MS approach showed that blood-to-brain T3 transport is significantly decreased in the MCT8-deficient BBB, corroborating the radiolabeled T3 transport assays.

    “The MS approach showed that blood-to-brain T3 transport is significantly decreased in the MCT8-deficient BBB, corroborating the radiolabeled T3 transport assays.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Engineered MCT8-corrected line (CS01iMCT8cor) displayed restored T3 transport, and MCT8-mutated line (CS03CTRmut) displayed deficient T3 transport.

    “these findings extended to the engineered MCT8-corrected line (CS01iMCT8cor), which displayed restored T3 transport, and to the MCT8-mutated line (CS03CTRmut), which now displayed deficient T3 transport.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Neural cultures of MCT8-deficient and control cells displayed similar levels of differentiation, apoptosis, and proliferation.

    “Furthermore, neural cultures of MCT8-deficient and control cells displayed similar levels of differentiation, apoptosis, and proliferation.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Findingown data

    Electroporation of the gRNA in healthy background cells efficiently generated a variety of indel mutations from which the CS03iCTRmut was selected.

    “Electroporation of the gRNA in healthy background cells (CS03iCTR) (Figure S2A) efficiently generated a variety of indel mutations from which the CS03iCTRmut was selected.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Despite MCT8 playing a role in transporting T4 in and out of iBMECs, T4 transport across MCT8-deficient iBMECs was not significantly affected.

    “Intriguingly, despite the fact that MCT8 played a role in transporting T4 in and out of iBMECs, T4 transport across MCT8-deficient iBMECs was not significantly affected”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Inactivating mutations of MCT8 in males cause serum TH abnormalities and severe neuropsychomotor impairments.

    “Inactivating mutations of MCT8 in males cause serum TH abnormalities and severe neuropsychomotor impairments (Dumitrescu et al., 2004; Friesema et al., 2004).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Dumitrescu et al., 2004 source
    • cites Friesema et al., 2004 source

  • May combine two claims.

    Interpretationown data

    Although MCT8 deficiency leads to significantly reduced uptake of T3, chronic exposure to T3 in the media permits sufficient transport of T3 in MCT8-deficient neural cells and subsequent normal neuron maturation.

    “Importantly, although MCT8 deficiency leads to significantly reduced uptake of T3, chronic exposure to T3 in the media permits sufficient transport of T3 in MCT8-deficient neural cells and subsequent normal neuron maturation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    At least at this early stage of neural development, lack of functional MCT8 does not significantly affect proliferation, apoptosis, or neural cell differentiation.

    “Collectively, these results indicate that, at least at this early stage of neural development, the lack of a functional MCT8 does not significantly affect proliferation, apoptosis, or neural cell differentiation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Oatp1c1 is highly expressed in endothelial cells of the rodent BBB, but not the human BBB.

    “Oatp1c1 is highly expressed in endothelial cells of the rodent BBB (Roberts et al., 2008), but not the human BBB (Uchida et al., 2011)”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Roberts et al., 2008 source
    • cites Uchida et al., 2011 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    G-band karyotype analysis confirmed that the iPSC lines showed no chromosomal abnormalities.

    “G-band karyotype analysis confirmed that the iPSC lines showed no chromosomal abnormalities (Figures S1A–S1C).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Primary cultures were obtained under consent and privacy guidelines of the University of Chicago.

    “Primary cultures were obtained under consent and privacy guidelines of the University of Chicago.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    The iBMEC-MS platform can be used to measure the comparative transport of T3 analogs or to screen for drugs that could restore T3 transport across the BBB.

    “In addition to the transport of natural thyroid hormones, the iBMEC-MS platform can be used to measure the comparative transport of T3 analogs that have been explored to treat MCT8-deficient patients or to screen for drugs that could restore T3 transport across the BBB.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Research using adult human brain post-mortem tissue was conducted in compliance with the policies and principles contained in the Federal Policy for the Protection of Human Subjects.

    “Research was conducted in compliance with the policies and principles contained in the Federal Policy for the Protection of Human Subjects.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Patient 2558 has a single base pair deletion in the 3rd exon of the MCT8 gene, predicted to produce a truncated and non-functional MCT8 protein that fails to migrate to the plasma membrane.

    “Patient 2558 has a single base pair deletion in the 3rd exon of the MCT8 gene, predicted to produce a truncated and non-functional MCT8 protein that fails to migrate to the plasma membrane (Dumitrescu et al., 2004)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Dumitrescu et al., 2004 source

  • Classified as probably not a substantial claim.

    Interpretationown data

    Since MCT8-deficient neural cells can mature normally in the presence of T3, one therapeutic approach may be to activate T3 signaling using BBB-permeable analogs that can enter the CNS in an MCT8-independent fashion.

    “Since our data suggest that MCT8-deficient neural cells can mature normally in the presence of T3, one therapeutic approach may be to activate T3 signaling using BBB-permeable analogs that can enter the CNS in an MCT8-independent fashion.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    All procedures were performed in accordance with the IRB guidelines at Cedars-Sinai Medical Center under IRB-SCRO Protocols Pro00021505 and Pro00032834.

    “All procedures were performed in accordance with the IRB guidelines at the Cedars-Sinai Medical Center under IRB-SCRO Protocols Pro00021505 and Pro00032834.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Each monolayer was monitored before recordings to confirm the presence of a full monolayer of cells.

    “Each monolayer was monitored before recordings to confirm the presence of a full monolayer of cells.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Successful reprogramming of each iPSC clone was verified by immunocytochemistry for the pluripotency markers NANOG, TRA160, OCT4, SSEA4, TRA181 and SOX2 as well as alkaline phosphatase activity.

    “Successful reprograming of each iPSC clone was verified by immunocytochemistry (ICC) for the pluripotency markers NANOG, TRA160, OCT4, SSEA4, TRA181 and SOX2 as well as the activity of the pluripotency marker alkaline phosphatase (AP) (Figures S1A–S1C).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Neuronal maturation is a limiting factor in iPSC models of neurodegenerative diseases.

    “These findings also extend beyond the scope of MCT8 deficiency, as neuronal maturation is a limiting factor in iPSC models of neurodegenerative diseases (Ho et al., 2016).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ho et al., 2016

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductcitation

    The validity of the novel human cell model was supported by expression of MCT8, additional TH transporters LAT1, LAT2, MCT10, lower levels of OATP1C1, and DIO3.

    “The validity of this novel human cell model was supported by the expression of MCT8, along with additional TH transporters LAT1, LAT2, MCT10, and lower levels of OATP1C1, as well as the main human cerebral deidodinase DIO3 (Kaplan, 1984).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Kaplan, 1984 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    In both isogenic lines, PCR confirmed the absence of off-site mutations.

    “In both isogenic lines, PCR confirmed the absence of off-site mutations (Table S2) and karyotyping verified the lack of chromosomal abnormalities possibly evoked by the gene editing process (Figures S2F and S2G).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    CRISPR/Cas9 was used to generate isogenic lines with either induced or corrected MCT8 mutations in order to exclude clonal variation.

    “In order to exclude clonal variation, the CRISPR/Cas9 system was used to generate isogenic lines with either induced or corrected MCT8 mutations.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    The persistence of the MCT8 gene mutations in the iPSC lines was verified by DNA sequencing.

    “Finally, the persistence of the MCT8 gene mutations in the iPSC lines was verified by DNA sequencing (Figure S1E).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Any data that failed to meet assumptions necessary for parametric testing was log-transformed prior to analysis.

    “Any data that failed to meet assumptions necessary for parametric testing was log-transformed prior to analysis.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    DITPA transport is MCT8 independent and at a level that can be ascribed to paracellular diffusion.

    “This suggests that DITPA transport is MCT8 independent and at a level that can be ascribed to paracellular diffusion.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Residuals were inspected to confirm data met assumptions required for parametric testing and to confirm the absence of influential outliers.

    “Residuals were inspected to confirm data met assumptions required for parametric testing and to confirm the absence of influential outliers.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Monolayer fidelity was confirmed at the beginning and at the end of each experiment by measuring TEER.

    “Monolayer fidelity was confirmed at the beginning and at the end of each experiment by measuring TEER by an EVOM2 system and a Chopstick Electrode (World Precision Instruments).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    The iBMEC platform holds great potential for high-throughput screening of molecules that can be delivered into the human CNS or impact the diseased BBB.

    “More generally, the iBMEC platform holds great potential for high-throughput screening of molecules that can be delivered into the human CNS or impact the diseased BBB.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    MCT8 is critical for the transport of T3, but not T4, across the BBB model.

    “These results demonstrate that MCT8 is critical for the transport of T3, but not T4, across the BBB model.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Patient 3601 has a C to T transition that results in replacement of Proline to Leucine (P321L), causing the mutant MCT8 to not transport T3 across cell membranes.

    “patient 3601 has a C to T transition that results in replacement of Proline to Leucine (P321L) causing the mutant MCT8 to not transport T3 across cell membranes (Kersseboom et al., 2013).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Kersseboom et al., 2013 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    In both isogenic lines, karyotyping verified the lack of chromosomal abnormalities possibly evoked by the gene editing process.

    “In both isogenic lines, PCR confirmed the absence of off-site mutations (Table S2) and karyotyping verified the lack of chromosomal abnormalities possibly evoked by the gene editing process (Figures S2F and S2G).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    PluriTest confirmed that the iPSCs were pluripotent and novel.

    “In addition, cells were subjected to the array-based PluriTest (Muller el., 2011, Illumina), which confirmed that the iPSCs were pluripotent and novel (Figure S1D).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Muller el., 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    All experiments were performed in duplicates or triplicates with a minimum of three independent neural or iBMEC differentiations, including a single clone for each cell line.

    “All experiments were performed in duplicates or triplicates with a minimum of three independent neural or iBMEC differentiations, including a single clone for each cell line.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In the mouse brain, T4 may cross the BBB via other non-Mct8 transporters and can be converted into T3 by deiodination in astrocytes.

    “In the mouse brain, T4 may cross the BBB via other non-Mct8 transporters and can be converted into T3 by deiodination in astrocytes (Heuer and Visser, 2013).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Heuer and Visser, 2013 source
59 of 59

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Brain endothelial specific or enriched transporters are often indispensable for BBB barriergenesis, as for example, GLUT1, MFSD2A, and MCT8.

    “Brain endothelial specific or enriched transporters are often indispensable for BBB barriergenesis, as for example, the glucose transporter-1 (GLUT1) (649), sodium-dependent lysophosphatidylcholine (LPC) symporter, the major facilitator superfamily (MFS) domain-containing protein 2a (MFSD2A) (62), and monocarboxylic acid transporter MCT8 (611).”

    From Blood-Brain Barrier: From Physiology to Disease and Back (2019) · cites this paper as [611]

    The Results section reports that MCT8-deficient cells formed tight endothelial monolayers with properly localized tight-junction proteins and no significant difference in barrier resistance or paracellular permeability from controls. The Discussion identifies MCT8 as crucial for T3 transport across the BBB, not for formation of the barrier. Thus this paper does not support calling MCT8 indispensable for BBB barriergenesis. (LLM, conf=0.89)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Different P-gp inhibitors named for the efflux assay

    Minor

    The results identify PSC833 as the P-gp inhibitor used in the accumulation assay, but the corresponding methods list cyclosporin A instead.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Allan, 1944, Some examples of the inheritance of mental deficiency: apparently sex-linked idiocy and microcephaly, Am. J. Ment. Defic., 48, 325

Cited by

Sorted by citations

Related

Authors
Vatine, G. D., Al-Ahmad, A., Barriga, B. K., Svendsen, S., Salim, A., Garcia, L., Garcia, V. J., Ho, R., Yucer, N., Qian, T., Lim, R. G., Wu, J., Thompson, L. M., Spivia, W. R., Chen, Z., Van Eyk, J., Palecek, S. P., Refetoff, S., Shusta, E. V., & Svendsen, C. N.
Affiliations
  • Cedars-Sinai Medical Center (US)
  • University of Wisconsin–Madison (US)
  • University of California, Irvine (US)
  • University of Chicago (US)
Corresponding author
  • Shusta, Eric V.
  • Svendsen, Clive N.
ORCID
Venue
Cell Stem Cell
Publisher
Elsevier BV
Published
2017-06
Volume
20
Issue
6
Pages
831-843.e5
ISSN
  • 1875-9777 (ISSN-L)
  • 1934-5909
DOI
10.1016/j.stem.2017.04.002
PMC
PMC6659720
OpenAlex
W2615774542
Semantic Scholar
e6e6e861d7899311106db239646f8a3ce6787f60
Cited by
233
References
56
Citations by year
2026: 16 · 2025: 23 · 2024: 16 · 2023: 16 · 2022: 34 · 2021: 35 · 2020: 37 · 2019: 28 · 2018: 19 · 2017: 9
FWCI
10.37
Type
journal article
Language
en
Open access
Licence
Locations
  • Cell stem cell (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
Funders
  • Sherman Family Foundation
  • Board of Governors Regenerative Medicine Institute
  • Cedars-Sinai Medical Center (CNS)
  • NIH (NS083688, AA020476, NS085351, R37DK15070)
Topics
  • Life Sciences › Neuroscience › Neurology › Barrier Structure and Function Studies
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Pluripotent Stem Cells Research
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Disorders and Treatments
Keywords
MCT8 deficiency, psychomotor retardation, thyroid hormone transport, blood-brain barrier, induced pluripotent stem cells, thyroid hormone uptake, brain drug delivery, thyroid hormone transporters
MeSH terms
Blood-Brain Barrier, Cell Line, Female, Humans, Male, Neurons, Psychomotor Disorders, Monocarboxylic Acid Transporters, Symporters, Induced Pluripotent Stem Cells

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-27.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-27.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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