c-Cbl induced podocin ubiquitination contributes to the podocytes injury in diabetic nephropathy.

The ubiquitination function in diabetic nephropathy (DN) has attracted much attention, but there is a lack of information on its ubiquitylome profile. To examine the differences in protein content and ubiquitination in the kidney between db/db mice and db/m mice, we deployed liquid chromatography-mass spectrometry (LC-MS/MS) to conduct analysis. We determined 145 sites in 86 upregulated modified proteins and 66 sites in 49 downregulated modified proteins at the ubiquitinated level. Moreover, 347 sites among the 319 modified proteins were present only in the db/db mouse kidneys, while 213 sites among the 199 modified proteins were present only in the db/m mouse kidneys. The subcellular localization study indicated that the cytoplasm had the highest proportion of ubiquitinated proteins (31.87%), followed by the nucleus (30.24%) and the plasma membrane (20.33%). The enrichment analysis revealed that the ubiquitinated proteins are mostly linked to tight junctions, oxidative phosphorylation, and thermogenesis. Podocin, as a typical protein of slit diaphragm, whose loss is a crucial cause of proteinuria in DN. Consistent with the results of ubiquitination omics, the K261R mutant of podocin induced the weakest ubiquitination compared with the K301R and K370R mutants. As an E3 ligase, c-Cbl binds to podocin, and the regulation of c-Cbl can impact the ubiquitination of podocin. In conclusion, in DN, podocin ubiquitination contributes to podocyte injury, and K261R is the most significant site. c-Cbl participates in podocin ubiquitination and may be a direct target for preserving the integrity of the slit diaphragm structure, hence reducing proteinuria in DN.

MiR-107 overexpression attenuates neurotoxicity induced by 6-hydroxydopamine both in vitro and in vivo.

Alzheimer's disease (AD), the most common form of dementia, is a neurodegenerative disease characterized by neuronal atrophy in various brain regions. The expression of miR-107 is down-regulated in AD patients and target genes of miR-107 have been shown to directly involved in AD. In this study, we aimed to investigate the potential neuroprotective effects of miR-107. We first assessed brain activity in health controls and patients with AD. Then we examined miR-107 expression in SH-SY5Y and PC12 cells treated with 6-hydroxydopamine (6-OHDA), and investigated its function in cytotoxicity induced by 6-OHDA. We predicted a potential miR-107 target and assessed its role in miR-107 mediated effects and explored the intracellular signaling pathways downstream of miR-107. Finally, we assessed the function of miR-107 in the mouse model insulted by 6-OHDA. We found that 6-OHDA suppressed miR-107 expression and miR-107 played neuroprotective effects against 6-OHDA mediated cytotoxicity. We showed that miR-107 targeted programmed cell death 10 (PDCD10). MiR-107 suppressed PDCD10 expression and exogenous expression of PDCD10 inhibited miR-107 mediated neuroprotection. Additionally, we found that Notch signal pathway was downstream of miR-107/PDCD10. Finally, we found that 6-OHDA treatment suppressed miR-107 in mice and restoration of miR-107 alleviated motor disorder in the mouse model. Our study shows that miR-107 plays important neuroprotective roles against neurotoxicity both in vitro and in vivo by inhibiting PDCD10. Our findings confirm that miR-107 may be involved in AD pathogenesis and may be a therapeutic target for the treatment of AD-related impairments.