Augmented Mitochondrial Transfer Involved in Astrocytic PSPH Attenuates Cognitive Dysfunction in db/db Mice.

Diabetes-associated cognitive dysfunction (DACD) has ascended to become the second leading cause of mortality among diabetic patients. Phosphoserine phosphatase (PSPH), a pivotal rate-limiting enzyme in L-serine biosynthesis, has been documented to instigate the insulin signaling pathway through dephosphorylation. Concomitantly, CD38, acting as a mediator in mitochondrial transfer, is activated by the insulin pathway. Given that we have demonstrated the beneficial effects of exogenous mitochondrial supplementation on DACD, we further hypothesized whether astrocytic PSPH could contribute to improving DACD by promoting astrocytic mitochondrial transfer into neurons. In the Morris Water Maze (MWM) test, our results demonstrated that overexpression of PSPH in astrocytes alleviated DACD in db/db mice. Astrocyte specific-stimulated by PSPH lentivirus/ adenovirus promoted the spine density both in vivo and in vitro. Mechanistically, astrocytic PSPH amplified the expression of CD38 via initiation of the insulin signaling pathway, thereby promoting astrocytic mitochondria transfer into neurons. In summation, this comprehensive study delineated the pivotal role of astrocytic PSPH in alleviating DACD and expounded upon its intricate cellular mechanism involving mitochondrial transfer. These findings propose that the specific up-regulation of astrocytic PSPH holds promise as a discerning therapeutic modality for DACD.

Identification and validation of core genes for type 2 diabetes mellitus by integrated analysis of single-cell and bulk RNA-sequencing.

BACKGROUND: The exact mechanisms of type 2 diabetes mellitus (T2DM) remain largely unknown. We intended to authenticate critical genes linked to T2DM progression by tandem single-cell sequencing and general transcriptome sequencing data. METHODS: T2DM single-cell RNA-sequencing data were submitted by the Gene Expression Omnibus (GEO) database and ArrayExpress (EBI), from which gene expression matrices were retrieved. The common cell clusters and representative marker genes were ascertained by principal component analysis (PCA), t-distributed stochastic neighbor embedding (t-SNE), CellMarker, and FindMarkers in two datasets (GSE86469 and GSE81608). T2DM-related differentially expressed marker genes were defined by intersection analysis of marker genes and GSE86468-differentially expressed genes. Receiver operating characteristic (ROC) curves were utilized to assign representative marker genes with diagnostic values by GSE86468, GSE29226 and external validation GSE29221, and their prospective target compounds were forecasted by PubChem. Besides, the R package clusterProfiler-based functional annotation was designed to unveil the intrinsic mechanisms of the target genes. At last, western blot was used to validate the alternation of CDKN1C and DLK1 expression in primary pancreatic islet cells cultured with or without 30mM glucose. RESULTS: Three common cell clusters were authenticated in two independent T2DM single-cell sequencing data, covering neurons, epithelial cells, and smooth muscle cells. Functional ensemble analysis disclosed an intimate association of these cell clusters with peptide/insulin secretion and pancreatic development. Pseudo-temporal trajectory analysis indicated that almost all epithelial and smooth muscle cells were of neuron origin. We characterized CDKN1C and DLK1, which were notably upregulated in T2DM samples, with satisfactory availability in recognizing three representative marker genes in non-diabetic and T2DM samples, and they were also robustly interlinked with the clinical characteristics of patients. Western blot also demonstrated that, compared with control group, the expression of CDKN1C and DLK1 were increased in primary pancreatic islet cells cultured with 30 mM glucose for 48 h. Additionally, PubChem projected 11 and 21 potential compounds for CDKN1C and DLK1, respectively. CONCLUSION: It is desirable that the emergence of the 2 critical genes indicated (CDKN1C and DLK1) could be catalysts for the investigation of the mechanisms of T2DM progression and the exploitation of innovative therapies.

MMP1 regulated by NEAT1/miR-361-5p axis facilitates the proliferation and migration of cutaneous squamous cell carcinoma via the activation of Wnt pathway.

Cutaneous squamous cell carcinoma (CSCC) is one of the most malignant tumors worldwide. It has been validated that matrix metallopeptidase 1 (MMP1) expression was obviously up-regulated in CSCC tissues. However, its specific role in CSCC is still unclear. RT-qPCR analysis and western blot assays were used to measure the mRNA and protein expressions, respectively. MTT and colony formation assays were conducted to assess proliferative ability. Transwell assays were adopted to evaluate migratory and invasive abilities. Flow cytometry and caspase-3/8/9 activity assays were carried out to evaluate cell apoptosis. Relevant mechanism experiments were finally performed to delineate molecular relationship among genes. We found that the expression of MMP1 was up-regulated in CSCC cells, and knockdown of MMP1 suppressed cell proliferation and invasion in CSCC. Subsequently, miR-361-5p was validated to target MMP1. Moreover, miR-361-5p was proved to be sponged by nuclear paraspeckle assembly transcript 1 (NEAT1) in CSCC. We further demonstrated that NEAT1 could activate Wnt pathway to affect cell proliferation and invasion. Finally, miR-361-5p inhibition rescued the suppressing effects of NEAT1 depletion on cell proliferation, invasion as well as Wnt pathway in CSCC. In summary, MMP1 regulated by NEAT1/miR-361-5p axis facilitated CSCC malignant behaviors via Wnt pathway activation.