Hereditary Disorders of Manganese Metabolism: Pathophysiology of Childhood-Onset Dystonia-Parkinsonism in SLC39A14 Mutation Carriers and Genetic Animal Models

Mesenchymal stem cell-derived extracellular vesicles attenuate ferroptosis in aged hepatic ischemia/reperfusion injury by transferring miR-1275

With an aging global population, the proportion of aged donor livers in graft pools is steadily increasing. Compared to young livers, aged livers exhibit heightened susceptibility to hepatic ischemia/reperfusion injury (HIRI), which significantly limits their utilisation in liver transplantation (LT) and exacerbates organ shortages. Our previous study demonstrated that ferroptosis is a pivotal trigger for HIRI vulnerability in aged livers. However, effective clinical strategies for the inhibition of ferroptosis remain elusive. Utilizing an aged mouse HIRI model, primary hepatocytes, and human liver organoids, this study provides hitherto undocumented evidence that mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) effectively alleviate HIRI in aged livers by inhibiting ferroptosis. Mechanistically, miR-1275, which was significantly enriched within MSC-EVs, was transferred to hepatocytes. Subsequently, miR-1275 downregulated the expression of SLC39A14, a crucial iron transporter that is upregulated in aged livers and plays a pivotal role in promoting ferroptosis. Furthermore, we found a negative correlation between SLC39A14 levels and prognosis of aged donor liver recipients using clinical LT samples. Silencing miR-1275 in MSC-EVs or modulating SLC39A14 levels in aged livers reversed MSC-EV-mediated mitigation of ferroptosis. Collectively, these findings revealed the novel therapeutic potential of MSC-EVs in attenuating aged HIRI, suggesting a promising treatment for improving prognosis and preventing serious complications in recipients of aged liver grafts during LT.

METTL14-mediated m6A modification regulates endometrial receptivity by inhibiting SLC39A14

Endometrial receptivity is a complex process that prepares the endometrium for embryo implantation. Inadequate endometrial receptivity is one cause of implantation failure. This study aimed to explore the impact of METTL14-mediated m6A modification of SLC39A14 on endometrial stromal cells (ESCs). ESCs were transfected and subjected to CCK-8 viability assay, EdU proliferation assay, and flow cytometry cell cycle and apoptosis analyses. Autophagy-related proteins LC3, p62, and Beclin-1 were detected through western blotting. RIP was used to detect the interaction between METTL14 protein and SLC39A14 mRNA. Me-RIP was used to measure the m6A level of SLC39A14. Actinomycin D was used to assess the stability of SLC39A14 mRNA. METTL14 overexpression or SLC39A14 knockdown enhanced viability, promoted proliferation and cell cycle progression, restrained apoptosis, reduced LC3II/LC3I and Beclin-1 levels, and increased p62 expression in ESCs. METTL14 bound to SLC39A14 mRNA and increased SLC39A14 m6A modification, reducing SLC39A14 mRNA stability and SLC39A14 protein expression. SLC39A14 overexpression eliminated the effect of METTL14 overexpression on ESCs. In conclusion, METTL14 promotes proliferation and inhibits apoptosis and autophagy activation in ESCs by inhibiting SLC39A14.

Mitochondrially Transcribed dsRNA Mediates Manganese-induced Neuroinflammation

Manganese (Mn) is an essential trace element required for various biological functions, but excessive Mn levels are neurotoxic and lead to significant health concerns. The mechanisms underlying Mn-induced neurotoxicity remain poorly understood. Neuropathological studies of affected brain regions reveal astrogliosis, and neuronal loss, along with evidence of neuroinflammation. Here, we present a novel Mn-dependent mechanism linking mitochondrial dysfunction to neuroinflammation. We found that Mn disrupts mitochondrial transcriptome processing, resulting in the accumulation of complementary RNAs that form double-stranded RNA (dsRNA). This dsRNA is released to the cytoplasm, where it activates cytosolic sensor pathways, triggering type I interferon responses and inflammatory cytokine production. This mechanism is present in 100-day human cerebral organoids, where Mn-induced inflammatory responses are observed predominantly in mature astrocytes. Similar effects were observed in vivo in a mouse model carrying mutations in the SLC30A10 gene, which results in Mn accumulation. These findings highlight a previously unrecognized role for mitochondrial dsRNA in Mn-induced neuroinflammation and provide insights into the molecular basis of manganism. We propose that this mitochondrial dsRNA-induced inflammatory pathway has broad implications in for neurodegenerative diseases caused by environmental or genetic insults.

Manganese-Induced Parkinsonism: Evidence from Epidemiological and Experimental Studies

Manganese (Mn) exposure has evolved from acute, high-level exposure causing manganism to low, chronic lifetime exposure. In this latter scenario, the target areas extend beyond the globus pallidus (as seen with manganism) to the entire basal ganglia, including the substantia nigra pars compacta. This change of exposure paradigm has prompted numerous epidemiological investigations of the occurrence of Parkinson's disease (PD), or parkinsonism, due to the long-term impact of Mn. In parallel, experimental research has focused on the underlying pathogenic mechanisms of Mn and its interactions with genetic susceptibility. In this review, we provide evidence from both types of studies, with the aim to link the epidemiological data with the potential mechanistic interpretation.

A Proteomic Survey of the Cystic Fibrosis Transmembrane Conductance Regulator Surfaceome

The aim of this review article is to collate recent contributions of proteomic studies to cystic fibrosis transmembrane conductance regulator (CFTR) biology. We summarize advances from these studies and create an accessible resource for future CFTR proteomic efforts. We focus our attention on the CFTR interaction network at the cell surface, thus generating a CFTR 'surfaceome'. We review the main findings about CFTR interactions and highlight several functional categories amongst these that could lead to the discovery of potential biomarkers and drug targets for CF.