Protective Role of the Podocyte IL-15 / STAT5 Pathway in Focal Segmental Glomerulosclerosis.

Introduction: During glomerular diseases, podocyte-specific pathways can modulate the intensity of histological disease and prognosis. The therapeutic targeting of these pathways could thus improve the management and prognosis of kidney diseases. The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) pathway, classically described in immune cells, has been recently described in detail in intrinsic kidney cells. Methods: We describe STAT5 expression in human kidney biopsies from patients with focal segmental glomerulosclerosis (FSGS) and studied mice with a podocyte-specific Stat5 deletion in experimental glomerular diseases. Results: Here, we show, for the first time, that STAT5 is activated in human podocytes in FSGS. In addition, podocyte-specific Stat5 inactivation aggravates the structural and functional alterations in a mouse model of FSGS. This could be due, at least in part, to an inhibition of autophagic flux. Finally, interleukin 15 (IL-15), a classical activator of STAT5 in immune cells, increases STAT5 phosphorylation in human podocytes, and its administration alleviates glomerular injury in vivo by maintaining autophagic flux in podocytes. Conclusion: Activating podocyte STAT5 with commercially available IL-15 represents a potential new therapeutic avenue for FSGS.

Mycobacterium algericum sp. nov., a novel rapidly growing species related to the Mycobacterium terrae complex and associated with goat lung lesions.

A previously undescribed, rapid-growing, non-chromogenic Mycobacterium isolate from a goat lung lesion in Algeria is reported. Biochemical and molecular tools were used for its complete description and showed its affiliation to the Mycobacterium terrae complex. 16S rRNA, rpoB and hsp65 gene sequences were unique. Phylogenetic analyses showed a close relationship with M. terrae sensu stricto and Mycobacterium senuense. Culture and biochemical characteristics were generally similar to those of M. terrae and M. senuense. However, in contrast to M. terrae and M. senuense, the isolate was positive for urease production and had faster growth. The mycolic acid profile was distinct from those of M. terrae and M. senuense, thus further supporting the new taxonomic position of the isolate. We propose the name Mycobacterium algericum sp. nov. for this novel species. The type strain is TBE 500028/10(T) ( = Bejaia(T) = CIP 110121(T) = DSM 45454(T)).