Carboxypeptidase E Independently Changes Microtubule Glutamylation, Dendritic Branching, and Neuronal Migration

CPXM1 correlates to poor prognosis and immune cell infiltration in gastric cancer

Background

Gastric cancer (GC) is the fourth most common cause of cancer-related death and the fifth most frequent malignant cancer, especially advanced GC. Carboxypeptidase X member 1 (CPXM1) is an epigenetic factor involved in many physiological processes, including osteoclast differentiation and adipogenesis. Several studies have shown the association of CPXM1 with multiple tumors; however, the mechanism of CPXM1 involvement in the progression of GC is yet to be characterized.

Method

CPXM1 expression data were obtained from the Tumor Immune Estimation Resource. The Cancer Genome Atlas and the Gene Expression Omnibus databases were used to obtain patient-matched clinicopathological information, and the Kaplan-Meier plot database was utilized for the prognosis analysis of GC patients. The Catalog of Somatic Mutations in Cancer and cBioportal databases were adopted to study CPXM1 mutations in tumors. Next, we utilized the Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis for mechanism research. Furthermore, we performed tumor microenvironment and immune infiltration analysis based on CPXM1. Finally, we predicted sensitivity to several targeted drugs in GC patients based on CPXM1.CPXM1 is upregulated in GC and is correlated with poor prognosis, gender, and tumor stage in GC patients. Gene enrichment analysis suggested that CPXM1 may regulate the occurrence and progression of GC via the PI3K-AKT and TGF-β pathway. Moreover, CPXM1 expression results in an increase in the proportion of immune and stromal cells. Additionally, the proportion of plasma cells was inversely related to the expression of CPXM1, whereas macrophage M2 expression was proportionate to CPXM1 expression. Finally, six small-molecule drugs that showed notable variations in IC50 between two groups were screened.

Conclusion

These results suggested that CPXM1 regulates the progression of GC and may represent a novel target for the detection and treatment of GC.

Studying the Impact of Persistent Organic Pollutants Exposure on Human Health by Proteomic Analysis: A Systematic Review

Persistent organic pollutants (POPs) are organic chemical substances that are widely distributed in environments around the globe. POPs accumulate in living organisms and are found at high concentrations in the food chain. Humans are thus continuously exposed to these chemical substances, in which they exert hepatic, reproductive, developmental, behavioral, neurologic, endocrine, cardiovascular, and immunologic adverse health effects. However, considerable information is unknown regarding the mechanism by which POPs exert their adverse effects in humans, as well as the molecular and cellular responses involved. Data are notably lacking concerning the consequences of acute and chronic POP exposure on changes in gene expression, protein profile, and metabolic pathways. We conducted a systematic review to provide a synthesis of knowledge of POPs arising from proteomics-based research. The data source used for this review was PubMed. This study was carried out following the PRISMA guidelines. Of the 742 items originally identified, 89 were considered in the review. This review presents a comprehensive overview of the most recent research and available solutions to explore proteomics datasets to identify new features relevant to human health. Future perspectives in proteomics studies are discussed.

Mice heterozygous for a null mutation of Cpe show reduced expression of carboxypeptidase E mRNA and enzyme activity but normal physiology, behavior, and levels of neuropeptides

Carboxypeptidase E (CPE) is an essential enzyme that contributes to the biosynthesis of the vast majority of neuropeptides and peptide hormones. There are several reports claiming that small decreases in CPE activity cause physiological changes in animals and/or cultured cells, but these studies did not provide evidence that neuropeptide levels were affected by decreased CPE activity. In the present study, we tested if CPE is a rate-limiting enzyme in neuropeptide production using CpeNeo mice, which contain a neomycin cassette within the Cpe gene that eliminates enzyme expression. Homozygous CpeNeo/Neo mice show defects found in Cpe^fat/fat and/or Cpe global knockout (KO) mice, including greatly decreased levels of most neuropeptides, severely impaired fertility, depressive-like behavior, adult-onset obesity, and anxiety-like behavior. Removal of the neomycin cassette with Flp recombinase under a germline promoter restored expression of CPE activity and resulted in normal behavioral and physiological properties, including levels of neuropeptides. Mice heterozygous for the CpeNeo allele have greatly reduced levels of Cpe mRNA and CPE-like enzymatic activity. Despite the decreased levels of Cpe expression, heterozygous CpeNeo mice are behaviorally and physiologically identical to wild-type mice, with normal levels of most neuropeptides. These results indicate that CPE is not a rate-limiting enzyme in the production of most neuropeptides, casting doubt upon studies claiming small decreases in CPE activity contribute to obesity or other physiological effects.