Genetic Variants in Six-Transmembrane Epithelial Antigen of Prostate 4 Increase Risk of Developing Metabolic Syndrome in a Han Chinese Population

DIP2C polymorphisms are implicated in susceptibility and clinical phenotypes of autism spectrum disorder

BACKGROUND

Disco-interacting protein 2 C (DIP2C) has recently been reported as a new susceptibility gene for autism spectrum disorder (ASD) in a genome-wide association study.

METHODS

We evaluated associations between single nucleotide polymorphisms (SNPs) of DIP2C and ASD susceptibility in a case-control study (715 ASD cases and 728 controls) from Chinese Han.

RESULTS

We identified a significant association between SNPs (rs3740304, rs2288681, rs7088729, rs4242757, rs10795060, and rs10904083) and ASD susceptibility. Of note, rs3740304, rs2288681, and rs7088729 are positively associated with ASD under inheritance models; moreover, haplotypes with any two marker SNPs (rs3740304 [G], rs2288681 [C], rs7088729 [T], rs4242757 [C], rs10795060 [G], and rs10904083 [A]) are also significantly associated with ASD. Additionally, rs10795060 and rs10904083 are associated with "visual reaction" phenotypes of ASD.

CONCLUSIONS

DIP2C polymorphisms sort out the susceptibility and clinical phenotypes of autism spectrum disorder.

The Role of STAMP2 in Pathogenesis of Chronic Diseases Focusing on Nonalcoholic Fatty Liver Disease: A Review

Nonalcoholic fatty liver disease (NAFLD) is a major health issue. NAFLD can progress from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH). NASH can progress to cirrhosis or hepatocellular carcinoma. Unfortunately, there is no currently approved pharmacologic therapy for NAFLD patients. The six transmembrane protein of prostate 2 (STAMP2), a metalloreductase involved in iron and copper homeostasis, is well known for its critical role in the coordination of glucose/lipid metabolism and inflammation in metabolic tissues. We previously demonstrated that hepatic STAMP2 could be a suitable therapeutic target for NAFLD. In this review, we discuss the emerging role of STAMP2 in the dysregulation of iron metabolism events leading to NAFLD and suggest therapeutic strategies targeting STAMP2.

Association Between DCC Polymorphisms and Susceptibility to Autism Spectrum Disorder

Autism spectrum disorder (ASD) represents a group of childhood-onset lifelong neuro-developmental disorders. However, the association between single nucleotide polymorphisms (SNPs) in the deleted in colorectal carcinoma (DCC) gene and ASD susceptibility remains unclear. We investigated the association between ASD susceptibility and seven SNPs in DCC on the basis of a case-control study (231 ASD cases and 242 controls) in Chinese Han. We found that there was no association between ASD susceptibility and the seven SNPs in DCC; however, T-A haplotype (rs2229082-rs2270954), T-A-T-C haplotype (rs2229082-rs2270954-rs2292043-rs2292044), C-G-T-C-T haplotype (rs934345-rs17753970-rs2229082-rs2270954-rs2292043), C-G-T-C-T-G haplotype (rs934345-rs17753970-rs2229082-rs2270954-rs2292043-rs2292044), and G-G-T-C-C-C-C haplotype (rs934345-rs17753970-rs2229082-rs2270954-rs2292043-rs2292044-rs16956878) were associated with ASD susceptibility. Our results indicate that the haplotypes formed on the basis of the seven SNPs in DCC may be implicated in ASD.

Tumor Necrosis Factor Alpha-Induced Proteins in Malignant Tumors: Progress and Prospects

Tumor necrosis factor (TNF) is the first cytokine used in tumor biotherapy, but TNF-related drugs are limited by the lack of specific targets. Tumor necrosis factor alpha-induced proteins (TNFAIPs), derived from TNF, is a protein family and participates in proliferation, invasion and metastasis of tumor cells. In order to better understand biological functions and potential roles of TNFAIPs in malignant tumors, this paper in the form of “Gene–Protein–Tumor correlation” summarizes the biological characteristics, physiological functions and mechanisms of TNFAIPs by searching National Center of Biotechnology Information, GeneCards, UniProt and STRING databases. The relationship between TNFAIPs and malignant tumors is analyzed, and protein–protein interaction diagram in members of TNFAIPs is drawn based on TNF for the first time. We find that TNF as a key factor is related to TNFAIP1, TNFAIP3, TNFAIP5, TNFAIP6, TNFAIP8 and TNFAIP9, which can be directly involved in activating TNFAIP1, TNFAIP5, TNFAIP8 and TNFAIP9. We confirm that the mechanism of TNFAIP1, TNFAIP2 and TNFAIP3 inducing tumors may be related to NF-κB signaling pathway, but the mechanism of tumor induction by other members of TNFAIPs is not clear. In the future, translational studies are needed to explore the mechanisms of TNF-TNFAIPs-tumors.

STEAP4 Inhibits HIF-1α/PKM2 Signaling and Reduces High Glucose-Induced Apoptosis of Retinal Vascular Endothelial Cells

BACKGROUND

Diabetic retinopathy (DR) is a vascular lesion induced by high glucose. STEAP4 is an indispensable membrane protein, which is closely related to hyperglycemic-induced cell inflammation and injury, while STEPT4 has not been studied in hyperglycemic-induced retinal vascular endothelial cell injury.

METHODS

The expression of STEAP4 was detected by RT-qPCR and Western blot. CCK-8 was used to detect cell survival. STEAP4 was overexpressed by cell transfection. The expressions of cytokines TNF-α, IL-1, IL-6, ICAM-1, MDA, SOD and ROS were detected by ELISA. Cell apoptosis was detected by flow cytometry. The expressions of proteins associated with cell damage VEGF, KLF2, eNOS and apoptosis-related proteins Bax, cleaved caspase3 and Bcl2 were detected by Western blot. Finally, the expressions of HIFα and PKM2 were detected by immunofluorescence and Western blot.

RESULTS

The expression of STEAP4 in hyperglycemic-induced retinal vascular endothelial cells (HRCECs) decreased gradually. Overexpression of STEAP4 reduced inflammation and apoptosis of HRCECs and improved dysfunction of them. Meanwhile, overexpression of steap4 inhibited the expression of HIF-1α/PKM2 signal.

CONCLUSION

STEAP4 can be a potential therapeutic target for diabetic retinopathy by inhibiting HIF1/PKM2 signaling to reduce hyperglycemic-induced retinal cell apoptosis.

Psychological distress in cancer patients in a large Chinese cross-sectional study

BACKGROUND

Although psychological distress is common among patients with chronic diseases, the degree of risk for developing psychological distress is not well-established. Our aim with this study is to determine the odds ratio for psychological distress in patients with cancer as compared to either 1) patients with chronic disease patients without cancer, or 2) healthy controls in a large representative sample of Chinese population.

METHODS

Using a multistage, stratified cluster sampling method, 21,101 subjects 18-79 years old were interviewed face-to-face in Jilin province, China. Their psychological status was assessed with the 12-item General Health Questionnaire (GHQ-12). A total score of ≥4 was used as the threshold for determining psychological distress.

RESULTS

The prevalence of psychological distress was 14.08% across the entire sample: 10.63% in healthy controls; 14.81% in patients with chronic diseases; and 20% in patients with cancer. Multiple logistic regression analysis indicated that, as compared to the health controls, both cancer (OR = 1.609, 95%CI = 1.245-2.081) and chronic disease patients (OR = 1.330, 95%CI = 1.189-1.478) were more likely to suffer from psychological distress. Moreover, cancer patients had a higher risk of psychological distress than patients with chronic diseases (OR = 1.295, 95%CI = 1.049-1.600; p = 0.016). In addition, the cancer group (2.68 ± 0.114) demonstrated a higher GHQ score than the patients with chronic diseases (2.30 ± 0.017) and healthy controls (1.98 ± 0.029) (both p < 0.001).

CONCLUSION

Our results showed both a higher rate and greater degree of psychological distress in patients with cancer. This suggests a need for better psychological management in cancer patients to help alleviate their distress.

STEAP4: its emerging role in metabolism and homeostasis of cellular iron and copper

Preserving energy homeostasis in the presence of stressors such as proinflammatory cytokines and nutrient overload is crucial to maintaining normal cellular function. Six transmembrane epithelial antigen of the prostate 4 (STEAP4), a metalloreductase involved in iron and copper homeostasis, is thought to play a potentially important role in the cellular response to inflammatory stress. Genome-wide association studies have linked various mutations in STEAP4 with the development of metabolic disorders such as obesity, metabolic syndrome and type 2 diabetes. Several studies have shown that expression of Steap4 is modulated by inflammatory cytokines, hormones and other indicators of cellular stress and that STEAP4 may protect cells from damage, helping to maintain normal metabolic function. STEAP4 appears to be particularly relevant in metabolically oriented cells, such as adipocytes, hepatocytes and pancreatic islet cells. These cells struggle to maintain their function in iron or copper overloaded states, presumably due to increased oxidative stress, suggesting STEAP4's role in metal homeostasis is critical to the maintenance of cellular homeostasis in general, and in preventing the onset of metabolic disease. In this review, we explore genetic associations of STEAP4 with metabolic disorders, and we examine STEAP4 tissue expression, subcellular localization, regulation, structure and function as it relates to metabolic diseases. We then examine how STEAP4's role as a regulator of cellular iron and copper may relate to type 2 diabetes.

STEAP4 expression in human islets is associated with differences in body mass index, sex, HbA1c, and inflammation

OBJECTIVE

STEAP4 (six-transmembrane epithelial antigen of the prostate 4) is a metalloreductase that has been shown previously to protect cells from inflammatory damage. Genetic variants in STEAP4 have been associated with numerous metabolic disorders related to obesity, including putative defects in the acute insulin response to glucose in type 2 diabetes.

PURPOSE

We examined whether obesity and/or type 2 diabetes altered STEAP4 expression in human pancreatic islets.

METHODS

Human islets were isolated from deceased donors at two medical centers and processed for quantitative polymerase chain reaction. Organ donors were selected by status as non-diabetic or having type 2 diabetes. Site 1 (Edmonton): N = 13 type 2 diabetes donors (7M, 6F), N = 20 non-diabetic donors (7M, 13F). Site 2 (Virginia): N = 6 type 2 diabetes donors (6F), N = 6 non-diabetic donors (3M, 3F).

RESULTS

STEAP4 showed reduced islet expression with increasing body mass index among all donors (P < 0.10) and non-diabetic donors (P < 0.05) from Site 1; STEAP4 showed reduced islet expression among type 2 diabetes donors with increasing hemoglobin A1c. Islet STEAP4 expression was also marginally higher in female donors (P < 0.10). Among type 2 diabetes donors from Site 2, islet insulin expression was reduced, STEAP4 expression was increased, and white blood cell counts were increased compared to non-diabetic donors. Islets from non-diabetic donors that were exposed overnight to 5 ng/ml IL-1β displayed increased STEAP4 expression, consistent with STEAP4 upregulation by inflammatory signaling.

CONCLUSIONS

These findings suggest that increased STEAP4 mRNA expression is associated with inflammatory stimuli, whereas lower STEAP4 expression is associated with obesity in human islets. Given its putative protective role, downregulation of STEAP4 by chronic obesity suggests a mechanism for reduced islet protection against cellular damage.

STAMP2 is required for human adipose-derived stem cell differentiation and adipocyte-facilitated prostate cancer growth in vivo

Six Transmembrane Protein of Prostate 2 (STAMP2) has been implicated in both prostate cancer (PCa) and metabolic disease. STAMP2 has unique anti-inflammatory and pro-metabolic properties in mouse adipose tissue, but there is limited information on its role in human metabolic tissues. Using human adipose-derived stem cells (ASCs), we report that STAMP2 expression is dramatically upregulated during adipogenesis. shRNA-mediated STAMP2 knockdown in ASCs significantly suppresses adipogenesis and interferes with optimal expression of adipogenic genes and adipocyte metabolic function. Furthermore, ASC-derived adipocyte-mediated stimulation of prostate tumor growth in nude mice is significantly reduced upon STAMP2 knockdown in ASC adipocytes. These results suggest that STAMP2 is crucial for normal ASC conversion into adipocytes and their metabolic function, as well as their ability to facilitate PCa growth in vivo.

STAMPing at the crossroads of normal physiology and disease states

The six transmembrane protein of prostate (STAMP) proteins, also known as six transmembrane epithelial antigen of prostate (STEAPs), comprises three members: STAMP1-3. Their expression is regulated by a variety of stimuli, including hormones and cytokines, in varied settings and tissues with important roles in secretion and cell differentiation. In addition, they are implicated in metabolic and inflammatory diseases and cancer. Here, we review the current knowledge on the role of STAMPs in both physiological and pathological states.

STEAP4 and HIF-1α gene expressions in visceral and subcutaneous adipose tissue of the morbidly obese patients

AIM AND BACKGROUND

Obesity is a multifactorial disease in which environmental and genetic factors play an integrated role. Determining such target genes will help to elucidate the mechanisms underlying complex diseases such as obesity and diabetes which are usually seen together. Present study investigates the expression levels of STEAP4 and HIF-1α in visceral and subcutaneous adipose tissue.

PATIENTS AND METHODS

30(6M) morbidly obese patients undergoing bariatric surgery were included in the study. The patients were grouped according to the BMI as Group I (BMI <50kg/m(2)) and Group II (BMI ≥50kg/m(2)). Samples from visceral (omentum) and subcutaneous adipose tissues were obtained from each patient and real-time PCR (qPCR) was carried out for STEAP4 and HIF-1α gene expressions. Correlations between expression levels and clinical parameters were analyzed.

RESULTS

Mean age of the patients recruited to the study was 37.4 (18-64) years. Mean BMI was 46 (36-60) kg/m(2). STEAP4 expression in visceral adipose tissue was significantly higher than subcutaneous tissue. Visceral STEAP4 expression was also found to be reduced with increased BMI. It was also lower in patients with HbA1C over 6. Furthermore, expression of subcutaneous and visceral HIF-1α was significantly higher in Group II. There was a significant correlation between BMI, glycosylated hemoglobin, STEAP4 and HIF-1α gene expression.

CONCLUSIONS

Obesity and related disease are linked with the fact that there is a low grade inflammation in the adipose tissue of the obese individuals. Counter-regulatory processes such as STEAP4 protein family are overwhelmed by the proinflammatory stimuli. HIF-1α expression is increased due to tissue hypoxia and pro-inflammatory stimuli in the obese individuals, which results in increased visceral STEAP4 expressions.