Blimp1+ cells generate functional mouse sebaceous gland organoids in vitro

May combine two claims.

α6+;CD34+ HFSCs grown in similar conditions did not form these structures and instead resulted in non-organized spheroid clusters.

“Notably, when α6+;CD34+ HFSCs were grown in similar conditions we did not observe the formation of these structures. These cultures resulted in non-organized spheroid clusters highly similar to those recently reported20 (Supplementary Fig. 1g).”

• cites [20] Chacon-Martinez, C. A., Klose, M., Niemann, C., Glauche, I. & Wickstrom, S. A. Hair follicle stem cell cultures reveal self-organizing plasticity of stem cells and their progeny. EMBO J. 36, 151–164 (2017). sourceSupported

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

In the SG, cell proliferation is restricted to basal cells in the SG proliferative zone (SGPZ).

“In the SG, cell proliferation is restricted to basal cells, which reside at a defined region known as the SG proliferative zone (SGPZ).”

• cites [1] Niemann, C. & Horsley, V. Development and homeostasis of the sebaceous gland. Semin. Cell Dev. Biol. 23, 928–936 (2012). sourcePartly supported

  Section 2, “Organization and Functions of the Sebaceous Gland” (page unavailable), describes a proliferative basal layer at the gland’s periphery and says basal-cell division sustains renewal. It does not call this region the “SG proliferative zone” (SGPZ) or explicitly state that proliferation is restricted to it. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [22] Schneider, M. R. & Paus, R. Sebocytes, multifaceted epithelial cells: lipid production and holocrine secretion. Int. J. Biochem. Cell Biol. 42, 181–185 (2010). sourceNot checked — no full text of the source

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

During SG homeostasis, SGPZ cells migrate inward, become post-mitotic, and differentiate to lipid-filled sebocytes.

“During SG homeostasis, SGPZ cells migrate inward, become post-mitotic and differentiate to lipid-filled sebocytes (Fig. 2a)1, 22.”

• cites [1] Niemann, C. & Horsley, V. Development and homeostasis of the sebaceous gland. Semin. Cell Dev. Biol. 23, 928–936 (2012). sourcePartly supported

  Section 2 (page unavailable) describes proliferative cells at the gland’s periphery replenishing sebocytes, which accumulate lipids and are pushed toward the center. Section 3 calls mature sebocytes postmitotic, but does so for the developing gland. The copy therefore supports the broad maturation sequence, not the specific account that SGPZ cells themselves migrate inward and become postmitotic during homeostasis. (LLM, conf=0.83)

  Experimental — accuracy not yet measured
• cites [22] Schneider, M. R. & Paus, R. Sebocytes, multifaceted epithelial cells: lipid production and holocrine secretion. Int. J. Biochem. Cell Biol. 42, 181–185 (2010). sourceNot checked — no full text of the source

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

c-Myc has been reported as a key regulator of differentiation in the SG in vivo.

“Accordingly, c-Myc has been reported as a key regulator of differentiation in the SG in vivo31, 33.”

• cites [31] Watt, F. M., Frye, M. & Benitah, S. A. MYC in mammalian epidermis: how can an oncogene stimulate differentiation? Nat. Rev. Cancer 8, 234–242 (2008). sourceSupported
• cites [33] Cottle, D. L. et al. c-MYC-induced sebaceous gland differentiation is controlled by an androgen receptor/p53 axis. Cell Rep. 3, 427–441 (2013). sourceSupported

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

In an in vivo setting, c-Myc labels cells in the SGPZ and regulates both sebocyte proliferation and differentiation.

“In an in vivo setting, c-Myc labels cells in the SGPZ and regulates both sebocyte proliferation and differentiation31 (Supplementary Fig. 5a).”

• cites [31] Watt, F. M., Frye, M. & Benitah, S. A. MYC in mammalian epidermis: how can an oncogene stimulate differentiation? Nat. Rev. Cancer 8, 234–242 (2008). sourcePartly supported

  The ‘Intersection of Myc with other regulatory molecules’ section reports that Myc stimulates proliferation in the sebaceous gland and promotes sebaceous-gland differentiation. The ‘Modulating Myc activity in the epidermis in vivo’ section also reports increased sebaceous differentiation after Myc activation in mice. Our copy does not identify c-Myc as a marker of cells in the SGPZ; the Introduction locates detected c-Myc protein in zones of the hair follicle instead. No page numbers were provided for these passages. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

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

EGF enhances sebocyte proliferation, enlarges SGs, and increases sebum production.

“Specifically, we used hFGF-2 as it can drive sebocyte proliferation and hypertrophy16, EGF was administered as it enhances sebocyte proliferation, enlarges SGs and increases sebum production17 as well as R-spondin1, which promotes Wnt signaling that drives SG generation18.”

• cites [17] Dahlhoff, M., de Angelis, M. H., Wolf, E. & Schneider, M. R. Ligand-independent epidermal growth factor receptor hyperactivation increases sebaceous gland size and sebum secretion in mice. Exp. Dermatol. 22, 667–669 (2013). sourcePartly supported

  The Results report that mice with constitutively active EGFR had more proliferating gland cells, enlarged sebaceous glands, and higher sebum levels. But the study tested ligand-independent EGFR activation, not administered EGF. The Background also says EGF did not seem to increase proliferation of isolated human sebocytes and inhibited lipogenesis in human glands in vitro, so the claim overextends the mouse findings to EGF treatment. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

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

Blimp1 functions in terminally differentiated sebocytes as well as in granular IFE cells.

“Alternatively, it has recently been suggested that Blimp1 functions in terminally differentiated sebocytes8 as well as in granular IFE cells9, 10.”

• cites [8] Kretzschmar, K. et al. BLIMP1 is required for postnatal epidermal homeostasis but does not define a sebaceous gland progenitor under steady-state conditions. Stem Cell Rep. 3, 620–633 (2014). sourceSupported
• cites [9] Chiang, M. F. et al. Inducible deletion of the Blimp-1 gene in adult epidermis causes granulocyte-dominated chronic skin inflammation in mice. Proc. Natl Acad. Sci. USA 110, 6476–6481 (2013). sourceSupported
• cites [10] Magnusdottir, E. et al. Epidermal terminal differentiation depends on B lymphocyte-induced maturation protein-1. Proc. Natl Acad. Sci. USA 104, 14988–14993 (2007). sourceSupported

Classified as probably not a substantial claim.

R-spondin1 promotes Wnt signaling that drives SG generation.

“Specifically, we used hFGF-2 as it can drive sebocyte proliferation and hypertrophy16, EGF was administered as it enhances sebocyte proliferation, enlarges SGs and increases sebum production17 as well as R-spondin1, which promotes Wnt signaling that drives SG generation18.”

• cites [18] Gat, U., DasGupta, R., Degenstein, L. & Fuchs, E. De Novo hair follicle morphogenesis and hair tumors in mice expressing a truncated beta-catenin in skin. Cell 95, 605–614 (1998). sourcePartly supported

  The Abstract reports that stabilized β-catenin, a component of Wnt signaling, induced new hair follicles that formed sebaceous glands in mice. It does not identify R-spondin1 as the promoter of that signaling or test its effect on sebaceous gland generation. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

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

Noggin regulates sebocyte differentiation.

“We also administered the BMP inhibitor Noggin1 as it has been reported to regulate sebocyte differentiation19.”

• cites [19] Guha, U. et al. Bone morphogenetic protein signaling regulates postnatal hair follicle differentiation and cycling. Am. J. Pathol. 165, 729–740 (2004). sourceSupported

Classified as probably not a substantial claim.

The SG has been proposed to be replenished by distinct pools of stem cells or progenitors located in the HF or base of the SG.

“The SG has been proposed to be replenished by distinct pools of stem cells or progenitors located in the HF or base of the SG3–7.”

• cites [3] Horsley, V. et al. Blimp1 defines a progenitor population that governs cellular input to the sebaceous gland. Cell 126, 597–609 (2006). sourceNot checked — no full text of the source
• cites [4] Soteriou, D. & Fuchs, Y. A matter of life and death: stem cell survival in tissue regeneration and tumor formation. Nat. Rev. Cancer 18, 187–201 (2018). sourceNot checked — no full text of the source
• cites [5] Snippert, H. J. et al. Lgr6 marks stem cells in the hair follicle that generate all cell lineages of the skin. Science 327, 1385–1389 (2010). sourceNot checked — no full text of the source
• cites [6] Page, M. E., Lombard, P., Ng, F., Gottgens, B. & Jensen, K. B. The epidermis comprises autonomous compartments maintained by distinct stem cell populations. Cell Stem Cell 13, 471–482 (2013). sourceSupported
• cites [7] Blanpain, C. & Fuchs, E. Stem cell plasticity. Plasticity of epithelial stem cells in tissue regeneration. Science 344, 1242281 (2014). sourcePartly supported

  The HF homeostasis section (page not provided) says that sebaceous glands are maintained by distinct stem cells in the noncycling hair-follicle segment and that these cells arise from Blimp1-expressing progenitors. It does not locate a replenishing pool specifically at the base of the sebaceous gland. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

May combine two claims.

Cells prior to the onset or during early stage of differentiation express AR, which resides upstream and leads to the expression of FASN.

“Cells prior to the onset or during early stage of differentiation express AR, which is known to reside upstream and lead to the expression of FASN33.”

• cites [33] Cottle, D. L. et al. c-MYC-induced sebaceous gland differentiation is controlled by an androgen receptor/p53 axis. Cell Rep. 3, 427–441 (2013). sourceSupported

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

Terminally differentiated sebocytes and granular layer IFE keratinocytes are marked by the Blimp1 protein.

“Subsequently, it was described that terminally differentiated sebocytes8, as well as granular layer IFE keratinocytes9, 10 are marked by the Blimp1 protein.”

• cites [8] Kretzschmar, K. et al. BLIMP1 is required for postnatal epidermal homeostasis but does not define a sebaceous gland progenitor under steady-state conditions. Stem Cell Rep. 3, 620–633 (2014). sourceSupported
• cites [9] Chiang, M. F. et al. Inducible deletion of the Blimp-1 gene in adult epidermis causes granulocyte-dominated chronic skin inflammation in mice. Proc. Natl Acad. Sci. USA 110, 6476–6481 (2013). sourceSupported
• cites [10] Magnusdottir, E. et al. Epidermal terminal differentiation depends on B lymphocyte-induced maturation protein-1. Proc. Natl Acad. Sci. USA 104, 14988–14993 (2007). sourceSupported

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

Additional bacterial strains are suspected to play a role in the development of acne.

“As additional bacterial strains are suspected to play a role in the development of acne41”

• cites [41] O’Neill, A. M. & Gallo, R. L. Host–microbiome interactions and recent progress into understanding the biology of acne vulgaris. Microbiome 6, 177 (2018). sourceSupported

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

The differentiation program in the sebaceous gland is a multi-step process.

“The differentiation program in the SG is a multi-step process33.”

• cites [33] Cottle, D. L. et al. c-MYC-induced sebaceous gland differentiation is controlled by an androgen receptor/p53 axis. Cell Rep. 3, 427–441 (2013). sourceSupported

May combine two claims.

Blimp1-YFP+ cells display three morphologically distinct groups: small cells with high circularity, large cells resembling mature sebocytes, and differentiated IFE keratinocytes.

“Furthermore, using this approach, and in accordance with our previous findings, we detected three morphologically distinct groups: (I) small cells with high circularity, (II) large cells resembling mature sebocytes, and (III) differentiated IFE keratinocytes (Supplementary Fig. 1b).”

May combine two claims.

Ki67 is specifically expressed in the outer layers of the SG and is rarely seen in quiescent bulge HFSCs in vivo.

“As expected, analysis of skin wholemounts showed that Ki67 is specifically expressed in the outer layers of the SG and could rarely be seen in quiescent bulge HFSCs in vivo (Fig. 2b).”

May combine two claims.

Without EFNR factors in 3D culture, growth was significantly impaired and only a very limited number of organoids were generated.

“In contrast, when cells were grown without EFNR factors in 3D culture, growth was significantly impaired and only a very limited number of organoids were generated (Supplementary Fig. 1d, e).”

May combine two claims.

Blimp1 is expressed in cells at the base of the SG, in differentiated SG cells, and in interfollicular epidermal granular cells.

“Performing confocal Z-stack analyses, we discovered that Blimp1 is expressed in cells found at the base of the SG, as well as in differentiated SG cells and interfollicular epidermal (IFE) granular cells (Fig. 1a and Supplementary Fig. 1a).”

May combine two claims.

c-Myc expression mostly co-localized with Ki67 and MCM2 in the SGPZ and could not be detected in the inner compartment of the SG organoids.

“Alike normal SGs, we found that the expression of c-Myc mostly co-localized with Ki67 and MCM2 in the SGPZ and, as expected, could not be detected in the inner compartment of the SG organoids (Supplementary Fig. 5b, c).”

May combine two claims.

Confocal analysis of treated and control organoids stained with Ki67 shows increased proliferation upon androgen induction and decreased proliferation in retinoic acid derivatives-treated organoids.

“Confocal analysis of treated and control organoids stained with Ki67, showing increased proliferation upon androgen induction and decreased proliferation in retinoic acid derivatives-treated organoids.”

May combine two claims.

Hierarchical clustering grouped resected SGs, Blimp1+ cell-derived organoid samples, and 2D-grown Blimp1+ cells together, while HEK293T cells/brain and epidermis represented two additional distinct groups.

“Hierarchical clustering grouped together resected SGs, Blimp1+ cell-derived organoid samples and 2D-grown Blimp1+ cells, while HEK293T cells/brain and epidermis represented two additional distinct groups (Fig. 3d, e).”

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

Lipidomic analysis identified 6470 peaks representing single-charged molecular ions in both polarity modes.

“We identified 6470 peaks representing single-charged molecular ions in both polarity modes ([M + H]+, [M + NH4]+, [M-H]−, [M + HCO2]−).”

May combine two claims.

DBL-treated organoids display increased organoid size compared to control organoids, which is reduced upon treatments with retinoic acid derivatives.

“DBL-treated organoids display increased organoid size in compared to control organoids, which is reduced upon treatments with retinoic acid derivatives.”

May combine two claims.

The number of cells in the outer ring of the c-Myc-inhibited organoids had decreased, encompassing cells of smaller size in the inner zone.

“In complement, we found that the number of cells in the outer ring of the c-Myc-inhibited organoids had decreased, encompassing cells of smaller size in the inner zone (Fig. 4b, c and Supplementary Fig. 6b, c).”

May combine two claims.

c-Myc inhibition causes a more than 80% decrease in the number of Ki67+ cells and a substantial decrease in the levels of Cyclin D1 and c-Myc transcripts.

“we monitored cellular proliferation and found a more than 80% decrease in the number of Ki67+ cells, correlating to a substantial decrease in the levels of Cyclin D1 and c-Myc transcripts (Fig. 5g and Supplementary Fig. 8d).”

• AssumptionRests on an assumption: The 10058-F4 c-Myc inhibitor specifically inhibits c-Myc in organoids without off-target effects.

May combine two claims.

Blimp1+ cell-derived organoids mimic both the expression profile and homeostatic kinetics of sebaceous glands in vivo.

“Our detailed analyses indicated that Blimp1+ cell-derived organoids mimic both the expression profile and homeostatic kinetics of SGs in vivo.”

May combine two claims.

Key aspects of acne vulgaris include C. acnes colonization and induction of an inflammatory response, which are not present in the organoid model.

“key aspects of acne vulgaris include C. acnes colonization and the induction of an inflammatory response which are not present in our model.”

May combine two claims.

Blimp1 marks cells that reside in each of these locations: base of the sebaceous gland, terminally differentiated sebocytes, and granular layer IFE keratinocytes.

“we have been able to reconcile these observations and demonstrate that Blimp1 marks cells which reside in each of these locations.”

May combine two claims.

Administration of all three retinoids to DBL-treated organoids significantly decreases organoid size, with formulated ATRA yielding the most robust results.

“Administration of all three retinoids to DBL-treated organoids resulted in a significant decrease in organoid size with formulated ATRA yielding the most robust results (Fig. 5b and Supplementary Fig. 7e).”

May combine two claims.

The Blimp1 promoter is active in organoids, supplying further evidence for similarity to natural SGs.

“These findings indicate that the Blimp1 promoter is active in organoids, supplying further evidence for the similarity to natural SGs.”

May combine two claims.

Blimp1 does not mark a distinct cell population but is expressed in SG progenitors, mature sebocytes, and differentiated IFE cells.

“These findings suggest that Blimp1 does not mark a distinct cell population but is expressed in SG progenitors, mature sebocytes, and differentiated IFE cells, as recently reported3, 8–10.”

May combine two claims.

Cells from the outer layer either migrated or proliferated asymmetrically and gave rise to differentiated post-mitotic cells.

“In contrast, after 48 and 72 h we could clearly detect BrdU+ cells in the inner non-proliferating mass, indicating that cells from the outer layer either migrated or proliferated asymmetrically and gave rise to differentiated post-mitotic cells (Fig. 2g, h and Supplementary Fig. 4b, c).”

May combine two claims.

The described system can be employed to study the biology of the SG and as a drug screening platform for SG pathologies.

“Taken together, here we describe a system that can be employed to study the biology of the SG along with a drug screening platform for SG pathologies.”

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

Acne vulgaris is characterized by excessive keratin deposition and an increase in SG size, which is dependent upon sebocyte hyperproliferation and sebum production.

“Acne vulgaris is characterized by excessive keratin deposition and an increase in SG size, which is dependent upon sebocyte hyperproliferation and sebum production.”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source

May combine two claims.

Inner organoid cells do not proliferate and express lipids, suggestive of a differentiation program similar to that of a SG in vivo.

“The observations that inner organoid cells do not proliferate and express lipids is suggestive of a differentiation program similar to that of a SG in vivo.”

May combine two claims.

Blimp1+ cell-derived organoids mimic both the expression profile and homeostatic kinetics of SGs in vivo.

“Thus, our data indicate that Blimp1+ cell-derived organoids mimic both the expression profile and homeostatic kinetics of SGs in vivo.”

May combine two claims.

SG organoids can serve as a platform for studying initial stages of acne vulgaris and for identifying potential therapeutic targets.

“Furthermore, we identify a role for c-Myc in sebocyte proliferation and differentiation, and determine that SG organoids can serve as a platform for studying initial stages of acne vulgaris, making this a useful platform to identify potential therapeutic targets.”

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

Blimp1+ cells reside at the base of the SG and function as a sebocyte progenitor population.

“Blimp1+ cells reside at the base of the SG and have been reported to function as a sebocyte progenitor population3.”

• cites [3] Horsley, V. et al. Blimp1 defines a progenitor population that governs cellular input to the sebaceous gland. Cell 126, 597–609 (2006). sourceNot checked — no full text of the source

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

The c-Myc inhibitor 10058-F4 prevents the c-Myc-Max interaction and inhibits transcription of c-Myc target gene expression.

“To monitor the effect of inhibiting c-Myc activity we administered the specific c-Myc inhibitor, 10058-F4, which prevents the c-Myc-Max interaction and inhibits transcription of c-Myc target gene expression32.”

• cites [32] Follis, A. V., Hammoudeh, D. I., Daab, A. T. & Metallo, S. J. Small-molecule perturbation of competing interactions between c-Myc and Max. Bioorg. Med. Chem. Lett. 19, 807–810 (2009). sourceNot checked — no full text of the source

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

Androgen stimulation plays a critical role in regulating sebocyte proliferation and driving the emergence of acne.

“Androgen stimulation has been found to play a critical role in regulating sebocyte proliferation and driving the emergence of acne2, while PPARs have been shown to alter sebaceous lipid production and modulate acne formation34, 35.”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source

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

PPARs alter sebaceous lipid production and modulate acne formation.

“Androgen stimulation has been found to play a critical role in regulating sebocyte proliferation and driving the emergence of acne2, while PPARs have been shown to alter sebaceous lipid production and modulate acne formation34, 35.”

• cites [34] Trivedi, N. R. et al. Peroxisome proliferator-activated receptors increase human sebum production. J. Invest. Dermatol. 126, 2002–2009 (2006). sourceNot checked — no full text of the source
• cites [35] Lin, Q., Ruuska, S. E., Shaw, N. S., Dong, D. & Noy, N. Ligand selectivity of the peroxisome proliferator-activated receptor alpha. Biochemistry 38, 185–190 (1999). sourceNot checked — no full text of the source

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

The lipid-rich environment of acne vulgaris allows C. acnes to flourish, which in turn triggers inflammation via induction of pro-inflammatory cytokines.

“This serves as an ideal lipid-rich environment for C. acnes to flourish which in turn triggers inflammation via the induction of pro-inflammatory cytokines2.”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source

May combine two claims.

c-Myc regulates both sebocyte proliferation and differentiation as seen in normal SGs.

“Utilizing this platform, we find that c-Myc regulates both sebocyte proliferation and differentiation as seen in normal SGs.”

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

All-trans-retinoic acid (ATRA; Tretinoin), formulated ATRA (Ret-Avit), and 13-cis RA (Isotretinoin) are used worldwide for acne.

“Specifically, all-trans-retinoic acid (ATRA; Tretinoin), formulated ATRA (Ret-Avit), and 13-cis RA (Isotrtinoin) are used worldwide2.”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source

May combine two claims.

Administration of specific androgens and PPAR-stimulators results in an organoid model that recapitulates initial key aspects of acne development, including altered sebocyte proliferation, increased sebum production, and augmented organoid size.

“Taken together our findings indicate that administration of specific androgens and PPAR-stimulators can result in an organoid model that recapitulates initial key aspects of acne development including altered sebocyte proliferation, increase in sebum production, and augmented organoid size.”

• Also stated in: § Discussion · plain

  “This resulted in organoids that grew substantially in size and were characterized by excessive sebum production, increased sebocyte proliferation, and altered differentiation.”

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

Retinoids such as 13-cis RA have severe side-effects and concerns have been raised regarding their teratogenicity.

“Retinoids, such as 13-cis RA, are known to have severe side-effects and concerns have been raised regarding the teratogenicity of these compounds22.”

• cites [22] Schneider, M. R. & Paus, R. Sebocytes, multifaceted epithelial cells: lipid production and holocrine secretion. Int. J. Biochem. Cell Biol. 42, 181–185 (2010). sourceNot checked — no full text of the source

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

Blimp1 governs the size of sebaceous glands by repressing c-Myc gene expression.

“Blimp1 has been shown to govern the size of SGs by repressing c-Myc gene expression3.”

• cites [3] Horsley, V. et al. Blimp1 defines a progenitor population that governs cellular input to the sebaceous gland. Cell 126, 597–609 (2006). sourceNot checked — no full text of the source

May combine two claims.

The generated organoid model recapitulates critical aspects of sebaceous gland biology and could serve as a tool to study the SG in homeostasis and different pathologies.

“we have generated an organoid model that recapitulates critical aspects of SG biology, which could serve as a tool to study the SG in homeostasis and different pathologies.”

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

Acne vulgaris is a chronic disease of the pilosebaceous unit resulting from androgen-induced increased sebum production.

“Acne vulgaris is a chronic disease of the pilosebaceous unit resulting from androgen-induced increased sebum production40.”

• cites [40] Williams, H. C., Dellavalle, R. P. & Garner, S. Acne vulgaris. Lancet 379, 361–372 (2012). sourceNot checked — no full text of the source

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

Matrigel has been successfully utilized in several epithelial stem cell platforms.

“Next, we examined whether embedding cells in a basement membrane-like extracellular 3D environment such as Matrigel, which has been successfully utilized in several epithelial stem cell platforms, could enable establishment of SG organoids (Fig. 1d)12–14.”

• cites [12] Sato, T. & Clevers, H. Growing self-organizing mini-guts from a single intestinal stem cell: mechanism and applications. Science 340, 1190–1194 (2013). sourceNot checked — no full text of the source
• cites [13] Sato, T. & Clevers, H. SnapShot: growing organoids from stem cells. Cell 161, 1700–1700 e1701 (2015). sourceNot checked — no full text of the source
• cites [14] Clevers, H. Modeling development and disease with organoids. Cell 165, 1586–1597 (2016). sourceNot checked — no full text of the source

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

Linoleic acid is known to activate PPAR-ß.

“As a first step, we administered the potent dihydrotestosterone (DHT) androgen, the PPAR-γ BRL-49653 (BRL) activator and linoleic acid (LIN) known to activate PPAR-ß36.”

• cites [36] Rosenfield, R. L., Deplewski, D., Kentsis, A. & Ciletti, N. Mechanisms of androgen induction of sebocyte differentiation. Dermatology 196, 43–46 (1998). sourceNot checked — no full text of the source

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

Retinoids are derivatives of vitamin A and serve as the first-line treatment for acne.

“Retinoids are derivatives of vitamin A, which serve as the first-line treatment for acne2.”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source

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

PPAR activators and the potent androgen DHT are known to lead to hyperseborrhoea and increased sebocyte proliferation.

“We administered the organoids with PPAR activators and the potent androgen, DHT, which are known to lead to hyperseborrohoea and increased sebcote proliferation2.”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source

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

Key features of acne development include disturbed SG activity resulting in excessive sebum, altered sebocyte proliferation and differentiation, dysregulation of the hormonal environment, hyperkeratinization, colonization of C. acnes, and inflammation.

“Some of the key features of acne development include disturbed SG activity resulting in excessive sebum, altered sebocyte proliferation and differentiation, dysregulation of the hormonal environment, hyperkeratinization, colonization of C. acnes and inflammation2, 40.”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source
• cites [40] Williams, H. C., Dellavalle, R. P. & Garner, S. Acne vulgaris. Lancet 379, 361–372 (2012). sourceNot checked — no full text of the source

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

C. acnes upregulates the expression of pro-inflammatory cytokines in cultured sebocytes.

“it has been shown that C. acnes upregulates the expression of pro-inflammatory cytokines in cultured sebocytes2”

• cites [2] Moradi Tuchayi, S. et al. Acne vulgaris. Nat. Rev. Dis. Prim. 1, 15029 (2015). sourceNot checked — no full text of the source

May combine two claims.

c-Myc has a potential role in the pathogenesis of acne vulgaris and may be utilized as a therapeutic target.

“Taken together, these results indicate a potential role of c-Myc in the pathogenesis of acne vulgaris and suggest that it may be utilized as a therapeutic target.”

• AssumptionRests on an assumption: The 10058-F4 c-Myc inhibitor specifically inhibits c-Myc in organoids without off-target effects.

May combine two claims.

Administration of currently available acne treatments affected SG organoid size, proliferation, and differentiation, akin to acne in vivo.

“we show that administration of currently available acne treatments affected SG organoid size, proliferation, and differentiation, akin to acne in vivo.”

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

Blimp1+ cells reside exclusively at the base of the sebaceous gland and serve as a pool of progenitors.

“Initially, it was reported that Blimp1+ cells reside exclusively at the base of the SG and serve as a pool of progenitors3.”

• cites [3] Horsley, V. et al. Blimp1 defines a progenitor population that governs cellular input to the sebaceous gland. Cell 126, 597–609 (2006). sourceNot checked — no full text of the source

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

Prior findings show that overexpression of c-Myc leads to enhanced SG expansion, while conditional deletion of c-Myc results in decreased SG size, cell proliferation, and sebocyte differentiation.

“previously reported findings where overexpression of c-Myc led to enhanced SG expansion, while conditional deletion of c-Myc resulted in decreased SG size, cell proliferation, and sebocyte differentiation3, 29, 38, 39.”

• cites [3] Horsley, V. et al. Blimp1 defines a progenitor population that governs cellular input to the sebaceous gland. Cell 126, 597–609 (2006). sourceNot checked — no full text of the source
• cites [29] Arnold, I. & Watt, F. M. c-Myc activation in transgenic mouse epidermis results in mobilization of stem cells and differentiation of their progeny. Curr. Biol. 11, 558–568 (2001). sourceNot checked — no full text of the source
• cites [38] Zanet, J. et al. Endogenous Myc controls mammalian epidermal cell size, hyperproliferation, endoreplication and stem cell amplification. J. Cell Sci. 118, 1693–1704 (2005). sourceNot checked — no full text of the source
• cites [39] Waikel, R. L., Kawachi, Y., Waikel, P. A., Wang, X. J. & Roop, D. R. Deregulated expression of c-Myc depletes epidermal stem cells. Nat. Genet. 28, 165–168 (2001). sourceNot checked — no full text of the source

May combine two claims.

The combination of high numbers and location of ORO+ cells and the PPAR-γ increase suggests that retinol treatments can advance and alter the differentiation process.

“This result, in combination with the high numbers and location of ORO+ cells, suggests that retinol treatments can advance and alter the differentiation process.”

• AssumptionRests on an assumption: PPAR-γ is expressed during middle/late differentiation of sebocytes.

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

At least three mice were analyzed in in vivo experiments; organoids were grown from a mix of at least three mice and cultured in three independent biological repeats; all experiments were repeated at least twice.

“At least three mice were analyzed in in vivo experiments. Organoid were grown from a mix of at least three mice and cultured in three independent biological repeats. All experiments were repeated at least twice.”

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

All animal studies gained approval by the Committee on the Ethics of Animal Experiments of the Technion-Israel Institute of Technology.

“All animal studies gained approval by the Committee on the Ethics of Animal Experiments of the Technion-Israel Institute of Technology.”

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

All experiments were repeated at least twice in triplicates with similar results, and images are representative of organoids grown from a mix of at least three mice and cultured in three independent biological repeats.

“All experiments were repeated at least twice in triplicates with similar results and images are representative of organoids grown from a mix of at least three mice and cultured in three independent biological repeats.”

Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

The findings bring forward a platform that may be utilized for drug screening purposes, as well as for studying SG homeostasis, functions, and pathologies.

“In summary, our findings bring forward a platform that may be utilized for drug screening purposes, as well as for studying SG homeostasis, functions, and pathologies.”