Anti-DSP monoclonal antibody, clone FQS5494

Keratins (Ks), the intermediate filament (IF) proteins of epithelia, are coordinately expressed as pairs in a cell-lineage and differentiation manner. Cortical thymic epithelial cells (cTECs) predominantly express the simple epithelium keratin 8/18 (K8/K18) pair, whereas medullary thymic epithelial cells (mTECs) express the stratified epithelium K5/K14 pair, with TECs exhibiting K5 and K8 at the cortico-medullary junction in mature thymus. In the work reported here, we used wild-type (WT) and K8-knockout (K8-null) mice to address the contribution of K8/K18 IFs in the maintenance of the thymic epithelial structure. K8-null thymus maintained the differential cell segregation at the cortex versus the medulla observed in WT thymus, and the distribution of immature thymocytes at the cortex. The K8/K18 loss did not affect thymocyte development. However, it massively perturbed the TEC morphology both at the cortex and the medulla, along with a prominent depletion of cTECs. Such tissue alterations coincided with an increase in apoptosis and a reduced expression of Albatross (Fas-binding factor-1), also known for its capacity to bind K8/18 IFs. In addition, the K8/K18 loss affected the distribution of K5/K14-positive mTECs, but not their differentiation status. Together, the results indicate that K8/K18 IFs constitute key promoters of the thymic epithelium integrity.

Autosomal recessive forms of hair loss (alopecia) disorders have previously been associated with variants in at least five different genes including hairless (HR), desmoglein-4 (DSG4), desmocollin-3 (DSC3), lipase-H (LIPH), and lysophosphatidic acid receptor 6 (LPAR6). Here, we report the first familial case of alopecia resulting from a novel homozygous variant in the DSP gene. Since previous reports indicated the presence of heart abnormalities in patients carrying variants in the DSP gene; therefore, the echocardiographic evaluations of all affected members were performed. The results clearly excluded the presence of any form of heart abnormality in patients of the present family. Human genome scan mapped a disease locus on chromosome 6p25.1-p23, harboring DSP gene. Sequence analysis identified a novel homozygous missense variant [c.1493C > T (p.Pro498Leu)] in the DSP gene as the underlying genetic cause of non-syndromic alopecia in the family. The transition alters the completely conserved Pro498 residue in the SH3 domain of plakin that contributes to the stability and rigidity of this subfamily of spectrin repeats (SRs) containing proteins. Our study strengthens the evidence that hereditary hair loss disorders are genetically heterogeneous and imply that isolated form of alopecia is allelic with cardiocutaneous syndromes.