Transcription factor Pax6 regulates cell cycle progression and cell fate determination

The development of the central nervous system relies on the tight regulation of the neural progenitor proliferation and differentiation in order to generate new neurons. The transcription factor Pax6 coordinates these functions during the development of the mammalian forebrain, using the paired DNA binding domain. This is a bipartite DNA-binding domain constituted by two subdomains, the PAI and the RED, binding the DNA in a cooperative or independent manner in order to control specific targets. Focusing on the activity of Pax6 as regulator of cell proliferation and of cell fate determination, I aimed to understanding how these functions are regulated at the molecular level, using the developing ventral forebrain as a model. In this work the role of the RED domain of Pax6 as a regulator of cell cycle progression is investigated. The mutation of the RED subdomain leads to an increase of progenitors in active mitosis (phospho-histone3 positive cells) in the ventral telencephalon at midneurogenesis. Similar result was obtained in the progenitors of the dorsal telencephalon. The increment in the phospho-histone3 positive cells is followed by the increase in cell death in both dorsal and ventral forebrain. These evidences suggest impairments in the cell cycle progression of the progenitor cells in the RED domain mutant. The importance of full activity of the RED domain of Pax6 for the proper progression of the cell cytokinesis is shown via ex-vivo live imaging, performed on ventral developing forebrain of Pax6Leca2 mutant animals (RED domain mutant). To elucidate the molecular mechanisms underlying the observed phenotype, transcriptome of the Pax6Leca2 mutants and their age matching siblings is analyzed, identifying a potential candidate gene: the Holliday junction recognition protein (HJURP). The overexpression of the HJURP protein in the wild type progenitors in vitro resembles the impairment of cytokinesis observed in Pax6Leca2 mutant. In summary, my data suggest new mechanisms for the regulation of cytokinesis in progenitors mediated by the RED domain of Pax6 and indicate that the full functionality of the paired domain is a prerequisite for Pax6 to function as fate determinant

Transcriptional changes in the mammary gland during lactation revealed by single cell sequencing of cells from human milk.

Funder: Wellcome TrustUnder normal conditions, the most significant expansion and differentiation of the adult mammary gland occurs in response to systemic reproductive hormones during pregnancy and lactation to enable milk synthesis and secretion to sustain the offspring. However, human mammary tissue remodelling that takes place during pregnancy and lactation remains poorly understood due to the challenge of acquiring samples. We report here single-cell transcriptomic analysis of 110,744 viable breast cells isolated from human milk or non-lactating breast tissue, isolated from nine and seven donors, respectively. We found that human milk largely contains epithelial cells belonging to the luminal lineage and a repertoire of immune cells. Further transcriptomic analysis of the milk cells identified two distinct secretory cell types that shared similarities with luminal progenitors, but no populations comparable to hormone-responsive cells. Taken together, our data offers a reference map and a window into the cellular dynamics that occur during human lactation and may provide further insights on the interplay between pregnancy, lactation and breast cancer.UKRI-MRC project grant ((MR/S036059/1) UKRI-BBSRC project grant (BB/S006745/1) Breast Cancer Now Project Grant (2017MayPR907) CRUK Programme Foundation Award (DCRPGF\100010

Transcriptional changes in the mammary gland during lactation revealed by single cell sequencing of cells from human milk

AbstractUnder normal conditions, the most significant expansion and differentiation of the adult mammary gland occurs in response to systemic reproductive hormones during pregnancy and lactation to enable milk synthesis and secretion to sustain the offspring. However, human mammary tissue remodelling that takes place during pregnancy and lactation remains poorly understood due to the challenge of acquiring samples. We report here single-cell transcriptomic analysis of 110,744 viable breast cells isolated from human milk or non-lactating breast tissue, isolated from nine and seven donors, respectively. We found that human milk largely contains epithelial cells belonging to the luminal lineage and a repertoire of immune cells. Further transcriptomic analysis of the milk cells identified two distinct secretory cell types that shared similarities with luminal progenitors, but no populations comparable to hormone-responsive cells. Taken together, our data offers a reference map and a window into the cellular dynamics that occur during human lactation and may provide further insights on the interplay between pregnancy, lactation and breast cancer.</jats:p

The BAF complex interacts with Pax6 in adult neural progenitors to establish a neurogenic cross-regulatory transcriptional network

Numerous transcriptional regulators of neurogenesis have been identified in the developing and adult brain, but how neurogenic fate is programmed at the epigenetic level remains poorly defined. Here, we report that the transcription factor Pax6 directly interacts with the Brg1-containing BAF complex in adult neural progenitor

Tocilizumab therapy in rheumatoid arthritis with interstitial lung disease: a multicenter retrospective study

Interstitial lung disease (ILD) is the most severe extra-articular manifestation of rheumatoid arthritis (RA). Although it is responsible of 10-20% of all RA mortality, no controlled studies are available for the treatment of RA-ILD and its therapeutic approach is still debated

The BAF complex interacts with Pax6 in adult neural progenitors to establish a neurogenic cross-regulatory transcriptional network

Numerous transcriptional regulators of neurogenesis have been identified in the developing and adult brain, but how neurogenic fate is programmed at the epigenetic level remains poorly defined. Here, we report that the transcription factor Pax6 directly interacts with the Brg1-containing BAF complex in adult neural progenitors. Deletion of either Brg1 or Pax6 in the subependymal zone (SEZ) causes the progeny of adult neural stem cells to convert to the ependymal lineage within the SEZ while migrating neuroblasts convert to different glial lineages en route to or in the olfactory bulb (OB). Genome-wide analyses reveal that the majority of genes downregulated in the Brg1 null SEZ and OB contain Pax6 binding sites and are also downregulated in Pax6 null SEZ and OB. Downstream of the Pax6-BAF complex, we find that Sox11, Nfib, and Pou3f4 form a transcriptional cross-regulatory network that drives neurogenesis and can convert postnatal glia into neurons. Taken together, elements of our work identify a tripartite effector network activated by Pax6-BAF that programs neuronal fate