Constitutive expression of CX3CR1-BAC-Cre introduces minimal off-target effects in microglia

May combine two claims.

The adverse effects of CX3CR1-driven Cre-recombinase expression are limited to Cre-recombinase expression under the CX3CR1 promoter and to its induction during early postnatal ages.

“Interestingly, these effects were shown to be limited only to Cre-recombinase expression under the CX3CR1 promoter and to its induction during early postnatal ages8.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The available copy describes Cre expression under the adenovirus EIIa promoter in early mouse embryos (Abstract; no page given). Searches for CX3CR1, adverse effects, and early postnatal induction found no passage addressing whether such effects are limited to that promoter or age. (LLM, conf=0.77)

  Experimental — accuracy not yet measured

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

Early postnatal tamoxifen-mediated induction of CX3CR1CreER(Litt) enhances microglial synaptic engulfment in pups.

“early postnatal tamoxifen-mediated induction of CX3CR1CreER(Litt) has been shown to enhance microglial synaptic engulfment in pups8.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The available Abstract describes EIIa-Cre-mediated deletion of loxP-flanked sequences in early mouse embryos, not postnatal CX3CR1CreER induction or microglial synaptic engulfment. Searches for CX3CR1CreER, tamoxifen, and microglial engulfment found no relevant passage. Our copy displays a PDF link rather than the article body, so the claim cannot be assessed from the available text. (LLM, conf=0.74)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Tamoxifen-mediated CX3CR1CreER(Litt) expression increases Sholl intersections in pups (P7-P9).

“Tamoxifen-mediated Cre-recombinase expression under the promoter CX3CR1 (CX3CR1CreER(Litt)) has been shown to reduce IBA1+ microglia density in pups (P7-P9), while leading to increased IBA1+ microglia volume and Sholl intersections8.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The indexed Abstract (page not specified) describes Cre expression under the adenovirus EIIa promoter and deletion of loxP-flanked sequences in early mouse embryos. Searches for CX3CR1CreER, tamoxifen, microglia, and Sholl intersections found no passage addressing the claimed increase in Sholl intersections in P7–P9 pups. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Inducible CX3CR1YFP-CreER(Litt) expression causes a significant loss of P2RY12 expression in P15 microglia.

“The dyshomeostatic effects of inducible Cre-recombinase expression under CX3CR1 (CX3CR1YFP-CreER(Litt)) has also been characterized by a significant loss of P2RY12 expression in pups (P15) microglia9.”

• cites [9] Tsien, 1996, The essential role of hippocampal CA1 NMDA receptor-dependent synaptic plasticity in spatial memory, Cell sourceCould not verify

  The Introduction (p. 1) and Generation of CA1-Restricted NMDAR1 Mutant Mice (p. 3) describe Cre/loxP deletion of NMDAR1 in hippocampal CA1 pyramidal cells. Searches for CX3CR1YFP-CreER(Litt), P2RY12, P15 microglia, and related terms found no passage addressing the claimed loss of P2RY12 expression. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Early postnatal induction of CX3CR1CreER(Litt) upregulates microglial phagocytic function.

“The authors found a lower microglial density, an altered phenotype, upregulation of their phagocytic function, and DNA damage in the Cre+ microglia of the developing brain.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The Abstract (page not provided) describes EIIa-Cre-mediated deletion of loxP-flanked sequences in early mouse embryos. Searches for CX3CR1CreER, microglial phagocytosis, microglial density, and DNA damage found no passage addressing the claimed effects of early postnatal induction. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Early postnatal induction of CX3CR1CreER(Litt) increases anxiety-like behavior in adulthood.

“these unintended and non-specific effects of CX3CR1-driven Cre-recombinase expression in early postnatal microglia caused the animals to display increased anxiety-like behavior in adulthood8.”

• Also stated in: § The expression of CX3CR1-BAC-CRE does not affect the threat response or cause anxiety-like behavior in adulthood. · boosted

  “early postnatal tamoxifen-mediated induction of CX3CR1CreER(Litt) has been shown to increase anxiety-like behavior in adulthood, with CX3CR1CreER(Litt) animals that received tamoxifen spending significantly less time in the center of the open-field test (OFT) and in the open arms of the elevated-plus maze test (EPM)8.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The indexed Abstract (no page given) describes EIIa-driven Cre recombination in early mouse embryos, not CX3CR1-driven Cre expression in postnatal microglia. Searches for CX3CR1CreER, microglia, and adult anxiety-like behavior found no passage addressing the claimed behavioral effect; the available copy shows no article-body text beyond a PDF link. (LLM, conf=0.74)

  Experimental — accuracy not yet measured

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

Microglia develop from myeloid progenitors in the yolk sac at embryonic day E8.5.

“Microglia develop from their myeloid progenitors in the yolk sac at embryonic day (E)8.5”

• cites [10] Marino, 2000, Induction of medulloblastomas in p53-null mutant mice by somatic inactivation of Rb in the external granular layer cells of the cerebellum, Genes Dev. sourceCould not verify

  The Discussion and the section on EGL precursor cells describe neural and cerebellar precursors, not the origin of microglia. Searches for microglia, yolk-sac myeloid progenitors, and E8.5 found no passage addressing the claim. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Early postnatal induction of CX3CR1CreER(Litt) reduces microglial density in the developing brain.

“The authors found a lower microglial density, an altered phenotype, upregulation of their phagocytic function, and DNA damage in the Cre+ microglia of the developing brain.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The Abstract (page not provided) describes EIIa-cre-mediated deletion of DNA sequences in early mouse embryos, not CX3CR1CreER induction. Searches for microglial density, phagocytic function, and DNA damage found no passage in our copy addressing the attributed findings. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

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

The hippocampus is thought to be particularly vulnerable to insults.

“it is thought to be particularly vulnerable to insults17.”

• cites [17] Dworzak, 2015, Neuronal Cx3cr1 deficiency protects against amyloid β-Induced neurotoxicity, PLoS One sourcePartly supported

  The Discussion says hippocampal neurons are more susceptible than cortical neurons to Aβ toxicity. That supports particular vulnerability to one insult, but the claim generalizes to insults more broadly, which this passage does not establish. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

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

Microglia start to proliferate and colonize the CNS parenchyma before the blood-brain barrier is formed.

“and they start to proliferate and colonize the CNS parenchyma before the blood-brain barrier is formed10.”

• cites [10] Marino, 2000, Induction of medulloblastomas in p53-null mutant mice by somatic inactivation of Rb in the external granular layer cells of the cerebellum, Genes Dev. sourceCould not verify

  The Abstract and Discussion discuss astrocytes, neural precursors, and cerebellar development, not microglial colonization. Searches for microglial proliferation, CNS colonization, and blood-brain barrier formation found no passage addressing their timing. Page numbers are not available in our copy. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

The hippocampus recapitulates the developmental trajectory throughout life.

“Since the hippocampus recapitulates the developmental trajectory throughout life”

• cites [17] Dworzak, 2015, Neuronal Cx3cr1 deficiency protects against amyloid β-Induced neurotoxicity, PLoS One sourceCould not verify

  The Results describe Cx3cr1 expression in cultured postnatal mouse hippocampal neurons, not the hippocampus’s developmental trajectory throughout life. The Discussion notes that the study’s neonatal, in vitro model limits its application to the aging human CNS. Searches for the claimed trajectory and adult hippocampal neurogenesis found no passage addressing the claim. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

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

Tamoxifen-mediated CX3CR1CreER(Litt) expression increases IBA1+ microglia volume in pups (P7-P9).

“Tamoxifen-mediated Cre-recombinase expression under the promoter CX3CR1 (CX3CR1CreER(Litt)) has been shown to reduce IBA1+ microglia density in pups (P7-P9), while leading to increased IBA1+ microglia volume and Sholl intersections8.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The indexed Abstract describes EIIa-promoter Cre activity in early mouse embryos, not tamoxifen-mediated CX3CR1CreER activity or microglia in P7–P9 pups. Searches for CX3CR1CreER, IBA1, microglia volume, and Sholl intersections found no relevant passage. Our copy links to a PDF but does not include its body text, so the claim cannot be verified from it. (LLM, conf=0.75)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Early postnatal induction of CX3CR1CreER(Litt) causes DNA damage in microglia during the early postnatal period.

“The authors found a lower microglial density, an altered phenotype, upregulation of their phagocytic function, and DNA damage in the Cre+ microglia of the developing brain.”

• Also stated in: § Microglial DNA is not damaged by the constitutive expression of CX3CR1-BAC-Cre · plain

  “It has been shown that tamoxifen-mediated Cre-recombinase expression (CX3CR1CreER(Litt)) decreases the number of proliferating microglia, thereby suggesting decreased proliferation of early postnatal microglia, as well as induces DNA damage in the early postnatal period8.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The Abstract (page not supplied) describes EIIa-Cre-mediated deletion of loxP-flanked sequences in early mouse embryos, not early postnatal CX3CR1CreER(Litt) induction. Searches for CX3CR1CreER(Litt), microglia, DNA damage, density, and phagocytic function found no relevant passage in our copy; the article body is represented only by a PDF link. (LLM, conf=0.75)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Alterations in microglia can lead to alterations in behavior in mice.

“It is widely known that alterations in microglia can lead to alterations in behavior in mice5,13–15.”

• cites [5] Hoess, 1985, Mechanism of strand cleavage and exchange in the Cre-lox site-specific recombination system, J. Mol. Biol. sourceNot checked — no full text of the source
• cites [13] Maes, 2019, Targeting microglia with lentivirus and AAV: recent advances and remaining challenges, Neurosci. Lett. sourceSupported
• cites [14] Zhou, 2024, A comprehensive review of AAV-mediated strategies targeting microglia for therapeutic intervention of neurodegenerative diseases, J. Neuroinflammation sourcePartly supported

  The Introduction links microglial dysfunction to neurodegenerative diseases and describes those diseases as causing cognitive decline and motor impairment. It does not report that altering microglia changes behavior in mice; searches for “behavior” and “behavioral” found no such passage. The general link is supported, but the mouse-specific claim is not. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites [15] Paolicelli, 2022, Microglia states and nomenclature: a field at its crossroads, Neuron sourceSupported

Classified as probably not a substantial claim.

Tamoxifen-mediated CX3CR1CreER(Litt) expression decreases the number of proliferating microglia in the early postnatal period.

“It has been shown that tamoxifen-mediated Cre-recombinase expression (CX3CR1CreER(Litt)) decreases the number of proliferating microglia, thereby suggesting decreased proliferation of early postnatal microglia, as well as induces DNA damage in the early postnatal period8.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The Abstract (page not provided) describes EIIa-promoter-driven Cre recombinase activity in early mouse embryos. Searches for CX3CR1CreER(Litt), tamoxifen, microglial proliferation, and DNA damage found no passage addressing the claimed effect; the indexed copy shows an abstract and references but not the article body. (LLM, conf=0.73)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

Early postnatal induction of CX3CR1CreER leads to increased developmental synaptic pruning in the somatosensory cortex.

“This finding contrasts with the key finding from Sahasrabuddhe et al.8, which shows that early postnatal induction of CX3CR1CreER leads to IFN-1 signaling activation, increased developmental synaptic pruning in the somatosensory cortex, and increased anxiety-like behavior in adulthood.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The indexed Abstract describes EIIa-cre-mediated deletion of loxP-flanked sequences in early mouse embryos, not early postnatal CX3CR1CreER induction. Searches for CX3CR1CreER, synaptic pruning, and somatosensory cortex found no passage addressing the attributed finding; the available copy shows an abstract and references rather than the article body. (LLM, conf=0.74)

  Experimental — accuracy not yet measured

May combine two claims.

CX3CR1CreER(Jung) has been shown to have minimal off-target effects, with no alterations in homeostatic markers of microglia following early postnatal induction.

“Notably, unlike CX3CR1CreER(Litt), CX3CR1CreER(Jung) has been shown to have minimal off-target effects, with no alterations in homeostatic markers of microglia following early postnatal induction9.”

• cites [9] Tsien, 1996, The essential role of hippocampal CA1 NMDA receptor-dependent synaptic plasticity in spatial memory, Cell sourceCould not verify

  The Introduction (p. 1) and Generation of CA1-Restricted NMDAR1 Mutant Mice (p. 3) describe Cre/loxP deletion of NMDAR1 in hippocampal CA1 pyramidal cells, not the CX3CR1CreER(Jung) line. Searches for CX3CR1CreER, microglial homeostatic markers, and off-target effects found no passage addressing the claim. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

May combine two claims.

Loss and deficiency of the CX3CR1 receptor can alter microglial number, subsequently altering microglia-mediated synaptic pruning during developmental ages.

“Its loss and deficiency can alter microglial number, subsequently altering microglia-mediated synaptic pruning during developmental ages13,18.”

• cites [13] Maes, 2019, Targeting microglia with lentivirus and AAV: recent advances and remaining challenges, Neurosci. Lett. sourceCould not verify

  The Microglia-specific transgene expression section (page unavailable) discusses a Cx3cr1-based mouse model as a way to target microglia, not the effects of losing the receptor. Searches for CX3CR1 deficiency, microglial number, and developmental synaptic pruning found no passage in our copy addressing the claimed sequence of effects. (LLM, conf=0.74)

  Experimental — accuracy not yet measured
• cites [18] Zhao, 2018, Noninflammatory changes of microglia are sufficient to cause epilepsy, Cell Rep. sourcePartly supported

  The Results report reduced Cx3cr1 expression and increased microglial numbers in TSC1Cx3cr1CKO mice. The Discussion suggests that increased microglial numbers and phagocytosis could account for reduced synapse density, but it does not establish that CX3CR1 loss caused either change; it attributes the proliferation to elevated mTOR signaling following TSC1 deletion. The proposed effect on pruning is therefore only partly supported. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Our findings and previous studies recognize the drawbacks of adverse and off-target effects, especially when employing this tool to study naturally reactive cells, such as microglia.

“Nevertheless, our findings and previous studies8,9 recognize the drawbacks of adverse and off-target effects, especially when employing this tool to study naturally reactive cells, such as microglia.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The indexed copy’s Abstract describes efficient Cre-mediated deletion in early mouse embryos, while its remaining passages are references and links to figures. Searches for adverse or off-target effects, Cre toxicity, and microglia found no passage addressing those drawbacks; the article body is not present in the indexed text. (LLM, conf=0.73)

  Experimental — accuracy not yet measured
• cites [9] Tsien, 1996, The essential role of hippocampal CA1 NMDA receptor-dependent synaptic plasticity in spatial memory, Cell sourcePartly supported

  The Introduction (p. 1) and Comparison with Previous Evidence (p. 8) describe unintended effects of conventional gene knockouts and pharmacological interventions, including effects outside the intended brain region. They do not discuss microglia or adverse effects when using the paper’s Cre/loxP method to study naturally reactive cells; the paper instead presents that method as a way to limit those problems. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

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

Reduced time spent in the center zone is considered to be a marker of anxiety-like behavior.

“Reduced time spent in the center zone is considered to be a marker of anxiety-like behavior8,21.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The Abstract (p. 5860) describes Cre-mediated deletion of DNA sequences in mouse embryos, not a behavioral measure. Searches for center-zone time, open-field behavior, and anxiety found no passage in our copy addressing the claim. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites [21] Parkhurst, 2013, Microglia promote learning-dependent synapse formation through brain-derived neurotrophic factor, Cell sourceCould not verify

  The Behavioral testing protocols section lists rotarod training, cue-based fear conditioning, and novel object recognition, but does not discuss time spent in a center zone. Searches for center-zone time, anxiety-like behavior, and open-field testing found no passage in our copy addressing the claimed marker. (LLM, conf=0.72)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

The trigger for IFN-1 signaling in the inducible Cre model is DNA damage.

“which was the trigger for the IFN-1 signaling in the inducible Cre model8”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The available Abstract describes EIIa-Cre-mediated deletion of loxP-flanked sequences in early mouse embryos, but does not discuss IFN-1 signaling or DNA damage. Searches for those terms returned only the abstract and references; the indexed copy does not include the article's substantive full-text sections, so it cannot settle the claimed trigger. (LLM, conf=0.72)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Early postnatal induction of CX3CR1CreER leads to IFN-1 signaling activation.

“This finding contrasts with the key finding from Sahasrabuddhe et al.8, which shows that early postnatal induction of CX3CR1CreER leads to IFN-1 signaling activation, increased developmental synaptic pruning in the somatosensory cortex, and increased anxiety-like behavior in adulthood.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The Abstract describes EIIa-cre–mediated deletion of loxP-flanked sequences in early mouse embryos. Searches for CX3CR1CreER, early postnatal induction, and type I interferon signaling found no passage addressing the claimed effect. The copy also does not name a work by Sahasrabuddhe, so it cannot establish an actual source for the claim. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

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

The phosphorylated-gamma-H2AX antibody used to detect DNA damage here was the same as used in the previous study.

“The phosphorylated-gamma-H2AX antibody used to detect DNA damage here was the same as used in the previous study8”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The available Abstract describes Cre-loxP deletion in early mouse embryos, not DNA-damage detection. Searches for phosphorylated γ-H2AX, H2AX antibody, and immunostaining found no relevant passage; the available copy does not establish whether the same antibody was used. (LLM, conf=0.72)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

Early postnatal induction of CX3CR1CreER leads to increased anxiety-like behavior in adulthood.

“This finding contrasts with the key finding from Sahasrabuddhe et al.8, which shows that early postnatal induction of CX3CR1CreER leads to IFN-1 signaling activation, increased developmental synaptic pruning in the somatosensory cortex, and increased anxiety-like behavior in adulthood.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The Abstract (page not specified in our copy) describes EIIa-cre–mediated deletion of DNA sequences in early mouse embryos. Searches for CX3CR1CreER, postnatal induction, anxiety-like behavior, IFN-1 signaling, and synaptic pruning found no passage addressing the claimed adult behavioral effect. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

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

Escape behavior is considered to be an active defensive response dependent on increased PVN-CRH+ neuron activity.

“Escape behavior is considered to be an active defensive response dependent on increased PVN-CRH+ neuron activity20.”

• cites [20] Jung, 2000, Analysis of fractalkine receptor CX(3)CR1 function by targeted deletion and green fluorescent protein reporter gene insertion, Mol. Cell Biol. sourceCould not verify

  The Results and Discussion describes CX3CR1-expressing microglia and their response to facial nerve injury, not escape behavior or PVN-CRH+ neurons. Searches for escape behavior and paraventricular corticotropin-releasing-hormone neurons found no passage addressing the attributed claim; the available passages give neither support nor a contrary finding. No page numbers were supplied for these passages. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

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

Reduced time spent exploring the open arms is used as a marker for anxiety-like behavior.

“Reduced time spent exploring the open arms is used as a marker for anxiety-like behavior8,22.”

• cites [8] Lakso, 1996, Efficient in vivo manipulation of mouse genomic sequences at the zygote stage, Proc. Natl. Acad. Sci. U. S. A. sourceCould not verify

  The available text describes Cre-mediated manipulation of mouse genomic sequences, not behavioral testing. Searches for open-arm exploration and the elevated plus maze found no passage linking reduced open-arm time to anxiety-like behavior; the available copy contains an abstract and references but not the article body. (LLM, conf=0.75)

  Experimental — accuracy not yet measured
• cites [22] Sahasrabuddhe, 2022, Cx3Cr1-Cre induction leads to microglial activation and IFN-1 signaling caused by DNA damage in early postnatal brain, Cell Rep. sourceNot checked — no full text of the source

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

The looming-shadow threat task assesses a mouse's response to a predator-like threat.

“The looming-shadow threat task assesses a mouse’s response to a predator-like threat20.”

• cites [20] Jung, 2000, Analysis of fractalkine receptor CX(3)CR1 function by targeted deletion and green fluorescent protein reporter gene insertion, Mol. Cell Biol. sourceCould not verify

  The Materials and Methods section describes contact hypersensitivity, STAg injections, and peripheral nerve injury, not a looming-shadow task. Searches for looming-shadow and predator-like defensive responses found no passage in our copy addressing that task. (LLM, conf=0.77)

  Experimental — accuracy not yet measured

May combine two claims.

Constitutive CX3CR1-BAC-Cre expression causes no difference in segment volume, soma volume, or average process thickness in the parietal cortex during early postnatal development.

“However, the Sholl-based morphology analysis revealed no difference in segment volume, soma volume, or average process thickness.”

Probably not a substantial claim: may not pass S1 (asserted), S4 (based). The quote only partly states this claim.

Constitutive CX3CR1-BAC-Cre expression causes no changes in any morphological metrics in the CA1 during early postnatal development.

“No changes in any morphological metrics were found with either marker, but there was a trend for a decrease in P2RY12 microglial volume in Cre+ animals (main effect of Genotype, F(1,35)=3.33, p=0.07; Fig.S3I).”

May combine two claims.

In adult mice, constitutive CX3CR1-Cre expression causes no significant changes in morphology or CD68 lysosome volume in the dentate gyrus.

“However, no significant changes in morphology or CD68 lysosome volume were found.”

May combine two claims.

Constitutive CX3CR1-BAC-Cre expression leads to subtle alterations in microglial phenotype in early postnatal ages, with no alterations in adult mouse behavior and enduring microglial changes only in the hippocampus.

“Our study demonstrates that constitutive CX3CR1-BAC-Cre expression leads to subtle alterations in microglial phenotype in early postnatal ages, with no alterations in adult mouse behavior and enduring microglial changes only in the hippocampus.”

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

Females have a lower volume of CD68 lysosomes overall than males in the CA3 during early postnatal development.

“Additionally, females had a lower volume of CD68 lysosomes overall than males (main effect of Sex, F(1,30)=5.752, p<0.05; Fig.S4J).”

May combine two claims.

Constitutive CX3CR1-BAC-Cre expression causes no changes in proliferation or DNA damage in any of the tested brain regions during early postnatal development.

“Interestingly, none of the tested brain regions showed changes due to genotype (Fig. 2 and Fig.S6–S9)”

The quote only partly states this claim.

Constitutive CX3CR1-BAC-Cre expression causes an increase in the volume of CD68 lysosomes normalized to microglial volume in the CA1 during early postnatal development.

“Furthermore, the volume of CD68 lysosomes normalized to microglial volume was increased as a result of the expression of Cre (main effect of Genotype, F(1,34)=7.986, p<0.05; Fig.S3J)”

The quote only partly states this claim.

Constitutive CX3CR1-BAC-Cre expression in females causes decreased IBA1 volume in the CA1 during early postnatal development.

“However, CX3CR1-Cre+ females showed decreased IBA1 volume (interaction of Genotype × Sex, F(1,31)=4.50, p<0.05, Šídák, p<0.05; Fig.S3C).”

The quote only partly states this claim.

Constitutive CX3CR1-BAC-Cre expression causes increased IBA1 volume in the CA3 during early postnatal development.

“The IBA1 volume was increased in Cre+ animals (main effect of Genotype, F(1,31)=6.28, p<0.05; Fig.S4C)”

Classified as probably not a substantial claim.

Microglia are highly heterogeneous throughout the brain, especially during the early postnatal period.

“It is known that, especially during the early postnatal period, microglia are highly heterogeneous throughout the brain16.”

• cites [16] Goldmann, 2013, A new type of microglia gene targeting shows TAK1 to be pivotal in CNS autoimmune inflammation, Nat. Neurosci. sourceNot checked — no full text of the source

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

Microglia play a vital role during typical development in shaping neuronal circuitry by pruning synapses.

“Microglia are known to play a vital role during typical development in shaping neuronal circuitry by pruning synapses2,11,12.”

• cites [2] Sternberg, 1986, Bacteriophage P1 cre gene and its regulatory region. Evidence for multiple promoters and for regulation by DNA methylation, J. Mol. Biol. sourceNot checked — no full text of the source
• cites [11] Schwenk, 1995, A cre-transgenic mouse strain for the ubiquitous deletion of loxP-flanked gene segments including deletion in germ cells, Nucleic Acids Res. sourceNot checked — no full text of the source
• cites [12] Feil, 1996, Ligand-activated site-specific recombination in mice, Proc. Natl. Acad. Sci. U. S. A. sourceNot checked — no full text of the source

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

Each group consisted of n=7-11 animals.

“Each group consisted of n=7–11 animals.”

May combine two claims.

Effects of constitutive CX3CR1-BAC-Cre expression can vary by age, brain region, and sex.

“although effects can vary by age, brain region, and sex”

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

The normalization of aberrant early postnatal microglial volume in females in the CA1 may indicate a transient shift in the developmental trajectory.

“which could also indicate a transient shift in the developmental trajectory.”

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

In this study, we did not test for direct effects of Cre expression on the immune function of microglia.

“In this study, we did not test for direct effects of Cre expression on the immune function of microglia.”

May combine two claims.

The increase in normalized CD68 lysosome volume in the CA1 appears to be driven by the decrease in microglial volume, with no significant difference in raw CD68 volume.

“but this appears to be driven by the decrease in microglial volume (i.e., no significant difference was found in the raw CD68 volume).”

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

All experiments were assessed blindly without prior knowledge of the experimental group.

“All experiments were assessed blindly without prior knowledge of the experimental group.”

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

The effects of constitutive CX3CR1-BAC-Cre expression align with the well-known heterogeneity of microglial populations.

“which aligns well with the well-known heterogeneity of microglial populations16.”

• cites [16] Goldmann, 2013, A new type of microglia gene targeting shows TAK1 to be pivotal in CNS autoimmune inflammation, Nat. Neurosci. sourceNot checked — no full text of the source

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

All experiments were performed in accordance with National Institutes of Health (NIH) guidelines and were approved by the Georgia State University Animal Care and Use Committee.

“All experiments were performed in accordance with National Institutes of Health (NIH) guidelines and were approved by the Georgia State University Animal Care and Use Committee.”

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

The decrease in microglial engulfment in the CA1 may be a compensatory mechanism for the decrease in gephyrin puncta density.

“which may suggest that the decrease in microglial engulfment was a compensatory mechanism.”

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

Subgroups of microglia are affected differently by Cre expression.

“Therefore, this result might point out that subgroups of microglia are affected differently by Cre expression.”

• AssumptionRests on an assumption: Different subsets of microglia can express each marker (IBA1 or P2RY12) in distinct levels.

Classified as probably not a substantial claim.

The phosphorylated-gamma-H2AX antibody generally produced diffuse and non-optimal staining results.

“but we found that it generally produced diffuse and non-optimal staining results.”

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

It is possible that the heterozygous deletion of CX3CR1-Cre in the inducible model could have produced more highly reactive microglia in specific brain regions.

“Therefore, it is possible that the heterozygous deletion of CX3CR1-Cre in the inducible model could have produced more highly reactive microglia in specific brain regions.”

• AssumptionRests on an assumption: The inducible CX3CR1-Cre (CX3CR1CreER(Litt)) employs the “knock-in” strategy, and even when bred to heterozygosity, CX3CR1CreER disrupts the diploidy of CX3CR1 endogenous gene and inserts the conditionally active Cre cassette into the CX3CR1 locus.