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I am not sure if this is technically a 'Hair Loss' study, so if anyone wants to move it to another category please do.
http://genesdev.cshlp.org/content/early/2017/05/02/gad.298703.117.full.pdf
Here is a quote from end of 7th page...(mice were used to prove this hypothesis, Ugh)
Based on our work, we concluded that the transcription factor KROX20 marks a lineage of resident hair shaft pro- genitor cells in the follicular matrix. Therefore, we hy- pothesized that Krox20 lineage cells are indispensible for hair growth.
Curious if any of the hair-science-savy people have opinions or thoughts.
If this is already posted and discussed--appologies.
From discussion section
We identified that the transcription factor KROX20 marks a cell lineage differentiating toward the hair shaft and that SCF in these hair shaft progenitor cells acts as a critical in- trinsic rheostat of hair pigmentation by managing mature melanocyte in the upper HF matrix. Ablation of Scf in Krox20 lineage cells consequently leads to a complete ab- sence of hair pigmentation, showing an indispensible non- cell-autonomous SCF contribution to melanocytes and that Krox20 lineage cells are the main source of SCF for follicular mature melanocytes to produce hair pigment. The completion of hair regeneration is dependent on the presence of HF Krox20 lineage cells as the cells giving rise directly to hair shafts
(Fig. 7I).
from the image description
(I) Schematic illustration of the roles of SCF and Krox20 lineage cells in hair pigmen- tation and development. Lineage tracing of Krox20 lineage cells revealed a dynamic expansion toward the direction of hair-producing cells during HF mor- phogenesis in the upper HF matrix (red box). Hair pro- genitor cells sustain differentiated melanocytes through non-cell-autonomous SCF/KIT signaling. Depletion of SCF in hair progenitor cells results in loss of hair pigmentation. Depletion of Krox20 line- age cells, the cells that differentiate into hair-produc- ing cells, results in impaired hair regeneration. Bar, 50 μm.
Interestingly, Lin28a transgenic mice exhibit a thickened hair coat due to prolonged anagen (Shyh-Chang et al. 2013). These results suggest that KROX20 could be a downstream regulator for Lin28/Let-7-mediated perinatal development in both nerves and skin.
Moreover, Wnt activation leads to up-regulation of KROX20, and this induction can be synergized by BMP inhibition with noggin (Saint- Jeannet et al. 1997; Baker et al. 1999). Taken together with our findings, the functional prediction for KROX20 in HF development could be a downstream effector of Wnt/β-catenin and BMP signaling, thereby directing HF stem cell differentiation.
In conclusion, this study delineates the origin of SCF expression in the hair matrix progenitors as a niche for follicular mature melanocytes and that their SCF is indispensible for hair pigmentation. In addition, SCF ex- pression in the matrix identifies immediate antecedents of hair shaft structural cells, and transcription factor KROX20 marks a sublineage of epithelial cells differen- tiating toward this hair shaft progenitor cells. Future studies to reconstitute SCF in the matrix niche will be in- teresting and will address whether hair hypopigmentation could be reversible. Furthermore, genetic ablation of Krox20 and global profiling of KROX20 transcriptional targets will help to elucidate its biological roles in epider- mal differentiation and HF development.
http://genesdev.cshlp.org/content/early/2017/05/02/gad.298703.117.full.pdf
Here is a quote from end of 7th page...(mice were used to prove this hypothesis, Ugh)
Based on our work, we concluded that the transcription factor KROX20 marks a lineage of resident hair shaft pro- genitor cells in the follicular matrix. Therefore, we hy- pothesized that Krox20 lineage cells are indispensible for hair growth.
Curious if any of the hair-science-savy people have opinions or thoughts.
If this is already posted and discussed--appologies.
From discussion section
We identified that the transcription factor KROX20 marks a cell lineage differentiating toward the hair shaft and that SCF in these hair shaft progenitor cells acts as a critical in- trinsic rheostat of hair pigmentation by managing mature melanocyte in the upper HF matrix. Ablation of Scf in Krox20 lineage cells consequently leads to a complete ab- sence of hair pigmentation, showing an indispensible non- cell-autonomous SCF contribution to melanocytes and that Krox20 lineage cells are the main source of SCF for follicular mature melanocytes to produce hair pigment. The completion of hair regeneration is dependent on the presence of HF Krox20 lineage cells as the cells giving rise directly to hair shafts
(Fig. 7I).
from the image description
(I) Schematic illustration of the roles of SCF and Krox20 lineage cells in hair pigmen- tation and development. Lineage tracing of Krox20 lineage cells revealed a dynamic expansion toward the direction of hair-producing cells during HF mor- phogenesis in the upper HF matrix (red box). Hair pro- genitor cells sustain differentiated melanocytes through non-cell-autonomous SCF/KIT signaling. Depletion of SCF in hair progenitor cells results in loss of hair pigmentation. Depletion of Krox20 line- age cells, the cells that differentiate into hair-produc- ing cells, results in impaired hair regeneration. Bar, 50 μm.
Interestingly, Lin28a transgenic mice exhibit a thickened hair coat due to prolonged anagen (Shyh-Chang et al. 2013). These results suggest that KROX20 could be a downstream regulator for Lin28/Let-7-mediated perinatal development in both nerves and skin.
Moreover, Wnt activation leads to up-regulation of KROX20, and this induction can be synergized by BMP inhibition with noggin (Saint- Jeannet et al. 1997; Baker et al. 1999). Taken together with our findings, the functional prediction for KROX20 in HF development could be a downstream effector of Wnt/β-catenin and BMP signaling, thereby directing HF stem cell differentiation.
In conclusion, this study delineates the origin of SCF expression in the hair matrix progenitors as a niche for follicular mature melanocytes and that their SCF is indispensible for hair pigmentation. In addition, SCF ex- pression in the matrix identifies immediate antecedents of hair shaft structural cells, and transcription factor KROX20 marks a sublineage of epithelial cells differen- tiating toward this hair shaft progenitor cells. Future studies to reconstitute SCF in the matrix niche will be in- teresting and will address whether hair hypopigmentation could be reversible. Furthermore, genetic ablation of Krox20 and global profiling of KROX20 transcriptional targets will help to elucidate its biological roles in epider- mal differentiation and HF development.
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