ADAM10 Research Articles

Androgens and Diet Regulation of SARS‐CoV‐2 Viral Entry Proteins: Implications for COVID‐19 Cardiorenal Outcomes Severity in Polycystic Ovary Syndrome

BackgroundThe susceptibility and the severity of coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) are associated with hyperandrogenism, obesity, and pre‐existing pulmonary, metabolic, renal or cardiac conditions. Hyperandrogenemia and ovarian dysfunction characterize polycystic ovary syndrome (PCOS), the most common endocrine disorder in premenopausal women. Women with PCOS have higher prevalence of obesity and higher incidence of cardiovascular diseases and renal injury, making them a population at risk for severe COVID‐19 outcomes.MethodsThree‐week‐old female mice were implanted with Silastic tubes filled with the nonaromatizable androgen dihydrotestosterone (DHT, 8 mg) or vehicle (empty tubes). Animals were maintained on high‐fat diet (HFD; 60% kcal fat) or low‐fat diet (LFD; 10% kcal fat, sucrose‐matched) for 90 days. Fat mass (EchoMRI), kidney and left ventricle (LV) weights as well as the cardiac and renal expression of the inflammatory markers interleukin‐6 (IL‐6), tumor necrosis factor‐α (TNF‐α), and interleukin‐1β (IL‐1β) were assessed. Moreover, circulatory, urinary, renal and cardiac levels of SARS‐CoV‐2 host cell receptor angiotensin converting enzyme 2 (ACE2) were quantified. Additionally, renal and cardiac mRNA and protein expression of the multiple cellular proteases required for viral entry (TMPRSS2, TMPRSS4, furin, cathepsin L, and ADAM17) were assessed.ResultsHFD exacerbated DHT‐mediated increases in fat mass (20.28 ± 1.10 vs. 6.78 ± 0.43 g, p<0.05), kidney weight (33.79 ± 1.35 vs. 26.52 ± 1.08 g, p<0.05), LV hypertrophy (7.48 ± 0.21 vs. 6.41 ± 0.28 g, p<0.05) and renal and cardiac expression of the inflammatory marker IL‐6 (1.5 and 2.5‐fold, respectively). PCOS mice on both diets showed higher urinary ACE2 (LFD: 18‐fold, HFD: 10‐fold) and altered renal mRNA and/or protein expression of all the measured targets. DHT upregulated renal TMPRSS2 (1.19 ± 0.04 vs. 0.98 ± 0.03 AU, p<0.05) and cathepsin L (2.64 ± 0.25 vs. 0.62 ± 0.25 AU, p<0.05) proteins in HFD‐fed DHT‐treated mice compared to LFD‐fed DHT‐treated mice. In the heart, LFD‐fed DHT‐treated mice showed no change in ACE2 and the cellular proteases on either the mRNA or protein levels except for ADAM17 protein that was significantly upregulated (1.63‐fold) compared to the vehicle‐treated group. On the other hand, while HFD‐fed DHT‐treated mice showed similar increase in cardiac ADAM17 protein (1.64‐fold vs. LFD‐fed vehicle‐treated), they showed higher mRNA expression of ACE2 (1.83‐fold) and furin (1.32‐fold) compared to the HFD‐fed vehicle‐treated mice.Conclusion and significanceOur findings highlight women with PCOS as a population with a high risk of COVID‐19 associated cardiac and renal complications. Further, our study suggests dietary control recommendations for optimal management of women with PCOS that can ultimately attenuate COVID‐19 cardiorenal outcomes.

Acute Interleukin‐6 Injection Influences Key Enzymes Involved in Amyloid Precursor Protein Processing in C57BL/6J Mice

Background Amyloid-beta plaques are a hallmark feature of Alzheimer's disease and are the product of aggregated amyloid-beta peptides. These peptides originate from amyloid precursor protein (APP) which is cleaved by beta secretase (BACE1), a key enzyme in the amyloidogenic cascade. Cleavage of APP by alpha secretase (ADAM10) however, does not result in amyloid-beta peptides and is a key enzyme in the non-amyloidogenic cascade. It is widely accepted that exercise reduces amyloid-beta production and plaque build-up in the brain, although it is unclear how exercise may be driving this observation. Interleukin-6 (IL-6) is an exercise induced cytokine and recent work in this area has demonstrated a role for acute exercise induced IL-6 in tissues such as muscle, adipose, and liver, however the role of acute IL-6 in the brain remains ill defined. The purpose of this study is to investigate if acute IL-6 injection will modulate key enzymes involved in APP processing, namely BACE1 and ADAM10. It is hypothesized that acute IL-6 injection will result in a shift towards the non-amyloidogenic processing of APP. Methods Male 10-week-old C57BL/6J mice were intraperitoneally injected with a weight-adjusted dose of recombinant murine IL-6 (3ng/g body mass) or an equivalent volume of saline. Brain tissue was acquired 15 minutes post-injection and the pre-frontal cortex and hippocampus regions were dissected. Results Acute IL-6 injection resulted in lower BACE1 activity in both the cortex (p=0.011) and the hippocampus (p=0.027) compared to the saline injected group. This was accompanied by lower BACE1 (p=0.007) and sAPPb(p=0.019) protein content in the hippocampus of mice injected with IL-6. No differences for BACE1 or sAPPb were observed in the cortex. ADAM10 activity was higher with IL-6 injection compared to saline in the hippocampus (p=0.018) and the cortex (p=0.055). A change in ADAM10 protein content was also observed with the ratio of pro to mature ADAM10 being higher in the cortex (p=0.033) of the IL-6 injected mice as compared to the saline injected control. Similarly, both pro (p=0.017) and mature (p=0.035) ADAM10 protein content were lower in the hippocampus of the IL-6 injected mice as compared to the saline injected control. Conclusions These results demonstrate that acute IL-6 modulates important enzymes involved in APP processing; pushing the cascade towards the non-amyloidogenic arm. This work further highlights regional brain differences in response to acute IL-6 and extends our knowledge of the function of acute IL-6 as a signalling molecule in the brain. Future work should determine if exercise induced IL-6 is in fact the main mediator of non-amyloidogenic APP processing.

Epigenetic Programming Induces Changes in Metabolic and Gene Expression and Reverses the Effects of Ang‐II Infusion in Male Mice

Cardiometabolic diseases are highly prevalent chronic illnesses associated with high risk morbidities. Maternal epigenetic programming modulates gene expression in offspring thus affecting their disease susceptibility later in life. The renin-angiotensin system (RAS) contributes to cardiometabolic homeostasis however, its over-activation is associated with cardiometabolic dysfunctions. Previously, we showed that perinatal exposure to high fat diet (HFD) leads to elevated BP, heart rate, fasting blood glucose (FBG) and weight gain in addition to elevated brain AT1R and ADAM17 gene expression exclusively in males. We hypothesize that perinatal HFD exposure leads to changes in RAS gene expression in peripheral tissues and these changes could be accentuated by low dose Angiotensin-II (Ang-II) revealing a stronger cardiometabolic dysfunction. C57BL6/J dams were fed a HFD or regular diet (RD) for 1 month and mated with RD-fed males. After weaning, offspring were put on RD resulting in two groups; HFD-RD (programmed) and RD-RD (control). At 3 months, offspring underwent 24 h BP recording (telemetry) and glucose tolerance test (GTT). Half of the mice in each group were then implanted with an osmotic pump filled with Ang-II (200 ng/kg/min/2 weeks) resulting in 4 groups; HFD-RD, RD-RD, HFD-RD+Ang-II, RD-RD+Ang-II. BP (24 h) was recorded weekly and GTT was repeated after the 2nd week for the Ang-II-treated mice. For all groups, Liver, muscle and adipose tissues were harvested and selected genes expression was quantified using qPCR. HFD-RD males exhibited higher FBG than RD-RD males (172.7 ±6 vs. 145.2 ±5 mg/dL, p=0.01) and higher blood glucose at 15 min (387.8 ±17 vs. 303.4 ±30 mg/dL, p=0.04). Surprisingly, only HFD-RD+Ang-II males showed lowered FBG level compared to HFD-RD males (139.7 ±8 mg/dL vs. 172.7 ±6, p=0.007) and at 15 min (279.8 ±19 mg/dL vs. 387.8 ±17, p=0.006). Interestingly, no metabolic changes were seen in females in any of the groups. In addition, Ang-II infusion had no effect on hemodynamic parameters in treated groups. Regarding gene expression, HFD-RD showed upregulation of insulin receptor (p=0.0019), ACE2 (p=0.008), and ADAM17 (p=0.04) in the liver compared to RD-RD. Conversely, in HFD-RD+Ang-II, insulin receptor and ACE2 were downregulated in the liver (p<0.0001) relative to HFD-RD. In muscle tissue, while ADAM17 was upregulated in RD-RD+Ang-II (p=0.039), there was no change in ADAM17 expression in HFD-RD+Ang-II. Additionally, AT1 receptor was strongly upregulated in RD-RD+Ang-II (p<0.0001) with a slight upregulation in HFD-RD+Ang-II (p=0.03). We conclude that perinatal exposure to HFD leads to a pre-diabetic state evident by elevated FBG, disturbed first phase insulin secretion, changes in insulin receptor and RAS gene expression exclusively in male mice. This programming reverses the effects of Ang-II, possibly switching signaling towards another angiotensin receptor involved in a protective mechanism.

Effects of SARS-CoV-2 on Cardiovascular System: The Dual Role of Angiotensin-Converting Enzyme 2 (ACE2) as the Virus Receptor and Homeostasis Regulator-Review.

Angiotensin-converting enzyme 2 (ACE2) is the entry receptor for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the cause of Coronavirus Disease-2019 (COVID-19) in humans. ACE-2 is a type I transmembrane metallocarboxypeptidase expressed in vascular endothelial cells, alveolar type 2 lung epithelial cells, renal tubular epithelium, Leydig cells in testes and gastrointestinal tract. ACE2 mediates the interaction between host cells and SARS-CoV-2 spike (S) protein. However, ACE2 is not only a SARS-CoV-2 receptor, but it has also an important homeostatic function regulating renin-angiotensin system (RAS), which is pivotal for both the cardiovascular and immune systems. Therefore, ACE2 is the key link between SARS-CoV-2 infection, cardiovascular diseases (CVDs) and immune response. Susceptibility to SARS-CoV-2 seems to be tightly associated with ACE2 availability, which in turn is determined by genetics, age, gender and comorbidities. Severe COVID-19 is due to an uncontrolled and excessive immune response, which leads to acute respiratory distress syndrome (ARDS) and multi-organ failure. In spite of a lower ACE2 expression on cells surface, patients with CVDs have a higher COVID-19 mortality rate, which is likely driven by the imbalance between ADAM metallopeptidase domain 17 (ADAM17) protein (which is required for cleavage of ACE-2 ectodomain resulting in increased ACE2 shedding), and TMPRSS2 (which is required for spike glycoprotein priming). To date, ACE inhibitors and Angiotensin II Receptor Blockers (ARBs) treatment interruption in patients with chronic comorbidities appears unjustified. The rollout of COVID-19 vaccines provides opportunities to study the effects of different COVID-19 vaccines on ACE2 in patients on treatment with ACEi/ARB.

ADAM17 Boosts Cholesterol Efflux and Downstream Effects of High-Density Lipoprotein on Inflammatory Pathways in Macrophages.

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Retraction: Glioma-Derived ADAM10 Induces Regulatory B Cells to Suppress CD8+ T Cells.

Retraction: Glioma-Derived ADAM10 Induces Regulatory B Cells to Suppress CD8+ T Cells.

Effect of Anti-TNF Therapy on Mucosal Apoptosis Genes Expression in Crohn's Disease.

Crohn's disease (CD) is a chronic immune-mediated disorder for which there is not a fully effective treatment. Moreover, biological therapy with anti-tumor necrosis factor-α (anti-TNF-α) monoclonal antibodies leads to an effective response in only 60–70% of patients. Our previous data suggested that specific loci polymorphism of the TNFRSF1B, FCGR3A, IL1R, IL1B, and FAS genes could be a predictor of the primary non-response to anti-TNF therapy in CD patients. In this work, we propose to explain this hypothesis by functional analysis in colon biopsies and in a cell culture model. Using the RT-qPCR analysis, we estimated the FCGR3A, IL1R, TNFRSF1B, IL1B, FAS, and ADAM17 genes mRNA level in colon biopsies material from inflamed and non-inflamed tissue from 21 CD patients (14 responders and 7 non-responders to anti-TNF therapy) and 6 controls, as well as in vitro in a peripheral blood mononuclear cells (PBMCs) from 14 CD patients (seven responders and seven non-responders to anti-TNF therapy) and eight controls cultured for 72 h with 10 μg/ml of anti-TNF antibody. Our findings demonstrated a significant down-regulation of TNFRSF1B gene expression in non-responders both in inflamed and in non-inflamed colon tissue, while the expression of the FCGR3A and IL1B genes was significantly up-regulated in non-responders in the inflamed colon region. In vitro research results indicate that the anti-TNF drug induced a significant decrease in TNFRSF1B, FCGR3A, and FAS gene expression in non-responders. These results show that altered TNFRSF1B, FCGR3A, and IL1B genes expression can be a predictor of the primary non-response to anti-TNF therapy in CD patients.

Voluntary wheel running is capable of improving cognitive function only in the young but not the middle-aged male APPSwe/PS1De9 mice

To determine whether voluntary wheel running could improve cognitive function from both the young and middle-aged APP/PS1 mice and the underlying mechanisms involved in. Young (9-weeks old) and middle-aged (24-weeks old) APP/PS1 mice were randomly assigned into control and exercise groups, respectively. Mice from exercise group had free and unlimited access to the running wheel for a total of 16 weeks. Voluntary exercise only improved cognitive function from young but not the middle-aged APP/PS1 mice. This might be owing to that in young APP/PS1 mice voluntary exercise reduced tau phosphorylation via inhibiting p-GSK3β activity, as well as reduced neuro-inflammation and elevated key proteins involved in synaptic plasticity. Additionally, exercise also elevated circulating L-Valine, Glucosamine, Formylanthranilic acid, Myristic acid level and improved gut microbiota profiles (i.e. elevated Oscillibacter, EF097061_g, EU454870_g, EU504554_g, EU505046_g and EF096172_g and reduced Alistipes). Improved circulating metabolites and intestinal microbiome might also contribute to improved learning and memory abilities post exercise. For the middle-aged APP/PS1 mice, exercise reduced ADAM10 and GFAP protein expression in hippocampus, with no notable alterations in circulating metabolites; additionally, mice from exercise group had markedly reduced abundance of the phyla Proteobacteria and Tenericutes, genera Bacteroides and Faecalibacterium, and elevated abundance of the genera Allobaculum. It is suggested that voluntary exercise should be initiated at an early adulthood period rather than at late stage in order to prevent cognitive decline or Alzheimer's disease.

CircRNA_100565 contributes to cisplatin resistance of NSCLC cells by regulating proliferation, apoptosis and autophagy via miR-337-3p/ADAM28 axis.

Circular RNAs (circRNAs) have been revealed to involve in the chemoresistance of various cancers, including non-small cell lung cancer (NSCLC). Here, we further investigate the role of circRNA_100565 in NSCLC cisplatin (DDP) resistance. The expression of circRNA_100565 and microRNA (miR)-337-3p, and ADAM metallopeptidase domain 28 (ADAM28) mRNA was detected using quantitative real-time polymerase chain reaction. Cell viability and apoptosis were measured by cell counting kit-8 assay and flow cytometry, respectively. Western blot was used to detect the level of ADAM28 and autophagy-related protein. The interaction between miR-337-3p and circRNA_100565 or ADAM28 was confirmed by dual-luciferase reporter assay or pull-down assay. In vivo experiments were conducted via the murine xenograft model. We found CircRNA_100565 was up-regulated in NSCLC DDP-resistant tissues and cell lines, and its high expression was associated with shorter overall survival of NSCLC patients. CircRNA_100565 deletion mitigated DDP resistance, reflected by the suppression of proliferation and autophagy, the reduction of IC50 value, as well as enhancement of apoptosis in DDP-resistant NSCLC cells. MiR-377-3p was confirmed to directly bind to circRNA_100565 or ADAM28 3'-UTR. Moreover, circRNA_100565 indirectly regulated ADAM28 expression by sponging miR-377-3p in NSCLC cells. Additionally, circRNA_100565 deletion-induced sensitivity of NSCLC resistant cells to DDP could be remarkably attenuated by miR-377-3p inhibition or ADAM28 re-expression. Meanwhile, circRNA_100565 knockdown contributed to the anti-tumor effects of DDP on NSCLC in vivo.CONCLUSION: CircRNA_100565 was an independent prognostic factor for NSCLC patient survival, and enhanced the resistance of NSCLC cells to cisplatin by regulating cell proliferation, apoptosis and autophagy via miR-337-3p/ADAM28 axis, shedding light on the development of a novel therapeutic strategy to boost the effectiveness of NSCLC chemotherapy.

Construction and Analysis of a ceRNA Network in Cardiac Fibroblast During Fibrosis Based on in vivo and in vitro Data.

AimsActivation of cardiac fibroblasts (CF) is crucial to cardiac fibrosis. We constructed a cardiac fibroblast-related competing endogenous RNA (ceRNA) network. Potential functions related to fibrosis of “hub genes” in this ceRNA network were explored.Materials and MethodsThe Gene Expression Omnibus database was searched for eligible datasets. Differentially expressed messenger (m)RNA (DE-mRNA) and long non-coding (lnc)RNA (DE-lncRNA) were identified. microRNA was predicted and validated. A predicted ceRNA network was constructed and visualized by Cytoscape, and ceRNA crosstalk was validated. A Single Gene Set Enrichment Analysis (SGSEA) was done, and the Comparative Toxicogenomics Database (CTD) was employed to analyze the most closely associated pathways and diseases of DE-mRNA in the ceRNA network. The functions of DE-mRNA and DE-lncRNA in the ceRNA network were validated by small interfering (si)RNA depletion.ResultsThe GSE97358 and GSE116250 datasets (which described differentially expressed genes in human cardiac fibroblasts and failing ventricles, respectively) were used for analyses. Four-hundred-and-twenty DE-mRNA and 39 DE-lncRNA, and 369 DE-mRNA and 93 DE-lncRNA were identified, respectively, in the GSE97358 and GSE116250 datasets. Most of the genes were related to signal transduction, cytokine activity, and cell proliferation. Thirteen DE-mRNA with the same expression tendency were overlapped in the two datasets. Twenty-three candidate microRNAs were predicted and the expression of 11 were different. Only two DE-lncRNA were paired to any one of 11 microRNA. Finally, two mRNA [ADAM metallopeptidase domain 19, (ADAM19) and transforming growth factor beta induced, (TGFBI)], three microRNA (miR-9-5p, miR-124-3p, and miR-153-3p) and two lncRNA (LINC00511 and SNHG15) constituted our ceRNA network. siRNA against LINC00511 increased miR-124-3p and miR-9-5p expression, and decreased ADAM19 and TGFBI expression, whereas siRNA against SNHG15 increased miR-153-3p and decreased ADAM19 expression. ADAM19 and TGFBI were closely related to the TGF-β1 pathway and cardiac fibrosis, as shown by SGSEA and CTD, respectively. Depletion of two mRNA or two lncRNA could alleviate CF activation.ConclusionsThe CF-specific ceRNA network, including two lncRNA, three miRNA, and two mRNA, played a crucial role during cardiac fibrosis, which provided potential target genes in this field.

Soluble Receptor for Advanced Glycation End-products (sRAGE) and Colorectal Cancer Risk: A Case-Control Study Nested within a European Prospective Cohort.

Overexpression of the receptor for advanced glycation end-product (RAGE) has been associated with chronic inflammation, which in turn has been associated with increased colorectal cancer risk. Soluble RAGE (sRAGE) competes with RAGE to bind its ligands, thus potentially preventing RAGE-induced inflammation. To investigate whether sRAGE and related genetic variants are associated with colorectal cancer risk, we conducted a nested case-control study in the European Prospective Investigation into Cancer and Nutrition (EPIC). Plasma sRAGE concentrations were measured by ELISA in 1,361 colorectal cancer matched case-control sets. Twenty-four SNPs encoded in the genes associated with sRAGE concentrations were available for 1,985 colorectal cancer cases and 2,220 controls. Multivariable adjusted ORs and 95% confidence intervals (CIs) were computed using conditional and unconditional logistic regression for colorectal cancer risk and circulating sRAGE and SNPs, respectively. Higher sRAGE concentrations were inversely associated with colorectal cancer (ORQ5vs.Q1, 0.77; 95% CI, 0.59-1.00). Sex-specific analyses revealed that the observed inverse risk association was restricted to men (ORQ5vs.Q1, 0.63; 95% CI, 0.42-0.94), whereas no association was observed in women (ORQ5vs.Q1, 1.00; 95% CI, 0.68-1.48; P heterogeneity for sex = 0.006). Participants carrying minor allele of rs653765 (promoter region of ADAM10) had lower colorectal cancer risk (C vs. T, OR, 0.90; 95% CI, 0.82-0.99). Prediagnostic sRAGE concentrations were inversely associated with colorectal cancer risk in men, but not in women. An SNP located within ADAM10 gene, pertaining to RAGE shedding, was associated with colorectal cancer risk. Further studies are needed to confirm our observed sex difference in the association and better explore the potential involvement of genetic variants of sRAGE in colorectal cancer development.

Increased ADAM12 Expression Predicts Poor Prognosis in Cervical Cancer Patients before General Anesthesia.

The current study aims to investigate the expression and diagnostic value of ADAM12 in patients with cervical cancer before general anesthesia. Seventy-eight cases of cervical cancer patients were included in the present study. RT-PCR and western blot were used to detect the expression of ADAM12 in cervical cancer tissues and adjacent tissues. Meanwhile, the expression of secretory ADAM12 in serum of cervical cancer patients and healthy people was detected by ELISA. The relationship between ADAM12 expression and prognosis of cervical cancer patients was analyzed. ROC analysis was carried out to explore the diagnostic value of ADAM12. Our data showed that the expression of ADAM12 mRNA and protein in cervical cancer tissues was significantly up-regulated compared with the adjacent tissues. ELISA assay showed that the content of ADAM12 in serum of cervical cancer patients was significantly higher than that of healthy people. Furthermore, ADAM12 expression was closely related to tumor invasion, TNM stage, lymph node metastasis and tumor differentiation. Kaplan-Meier survival analysis showed that the overall survival rate of patients with high ADAM12 was significantly lower than that of patients with low ADAM12 expression. The AUC of ADAM12, CEA, CA125, and SCC for cervical cancer was 0.893, 0.510, 0.769 and 0.550, respectively, while the highest value of AUC was 0.946 by the combination of the four indexes. In summary, increased expression of ADAM12 in cervical cancer patients can be used as an independent prognostic marker.

Effect of ADAM10 Gene Polymorphisms and Expression on Hepatocellular Carcinoma

Effect of ADAM10 Gene Polymorphisms and Expression on Hepatocellular Carcinoma

Sulfuretin exerts diversified functions in the processing of amyloid precursor protein

Sulfuretin is a flavonoid that protects cell from damage induced by reactive oxygen species and inflammation. In this study, we investigated the role of sulfuretin in the processing of amyloid precursor protein (APP), in association with the two catalytic enzymes the α-secretase a disintegrin and metalloproteinase (ADAM10), and the beta-site APP cleaving enzyme 1 (BACE1) that play important roles in the generation of β amyloid protein (Aβ) in Alzheimer's disease (AD). We found that sulfuretin increased the levels of the immature but not the mature form of ADAM10 protein. The enhanced ADAM10 transcription by sulfuretin was mediated by the nucleotides −444 to −300 in the promoter region, and was attenuated by silencing or mutation of transcription factor retinoid X receptor (RXR) and by GW6471, a specific inhibitor of peroxisome proliferator-activated receptor α (PPAR-α). We further found that sulfuretin preferentially increased protein levels of the immature form of APP (im-APP) but significantly reduced those of BACE1, sAPPβ and β-CTF, whereas Aβ1-42 levels were slightly increased. Finally, the effect of sulfuretin on BACE1 and im-APP was selectively attenuated by the translation inhibitor cycloheximide and by lysosomal inhibitor chloroquine, respectively. Taken together, (1) RXR/PPAR-α signaling was involved in sulfuretin-mediated ADAM10 transcription. (2) Alteration of Aβ protein level by sulfuretin was not consistent with that of ADAM10 and BACE1 protein levels, but was consistent with the elevated level of im-APP protein, suggesting that im-APP, an isoform mainly localized to trans-Golgi network, plays an important role in Aβ generation.

Involvement of Klotho, TNF‑&alpha; and ADAMs in radiation‑induced senescence of renal epithelial cells.

While radiation nephropathy is a major problem associated with radiotherapy, the exact mechanisms underlying its pathogenesis and the mediators involved in kidney deterioration remain to be elucidated. In view of the finding that senescence is typically increased post-irradiation, the present study examined whether ionizing radiation may cause kidney injury by enhancing premature senescence. The present study explored the relevance of the aging suppressor, Klotho, which has anti-aging activity and is highly expressed in murine renal cells/kidney tissues, under irradiation conditions. Firstly, the effects of radiation on mouse inner medullary collecting duct-3 (mIMCD-3) cells and kidney tissues of mice were assessed. Subsequently, the mRNA expression levels of Klotho, TNF-α and ADAM metallopeptidase domain (ADAM)9/10/17 were analyzed by reverse transcription-quantitative PCR following exposure to radiation. In addition, the levels of these proteins were measured by western blotting or ELISA. The results revealed that irradiation of mIMCD-3 cells clearly triggered cellular senescence. Notably, Klotho gene expression was considerably decreased in radiation-exposed mIMCD-3 cells and in the kidney tissues of irradiated BALB/c mice, and the corresponding translated protein was consistently expressed following radiation exposure. Moreover, expression of TNF-α, a negative regulator of Klotho, was significantly increased, whereas ADAM9/10/17, an ectodomain shedding enzyme of Klotho, was decreased in irradiated mIMCD-3 cells and in the kidney tissues of BALB/c mice. Collectively, these data suggested that TNF-α-mediated inhibition of Klotho expression and blockage of soluble Klotho formation via decreased ADAM expression following irradiation may contribute to the development of renal dysfunction through acceleration of radiation-induced cellular senescence.

\u03b1-Secretase nonsense mutation (ADAM10 Tyr167*) in familial Alzheimer\u2019s disease

BackgroundThe disintegrin metalloproteinase 10 (ADAM10) is the main α-secretase acting in the non-amyloidogenic processing of APP. Some ADAM10 gene variants have been associated with higher susceptibility to develop late-onset AD, though clear clinical-genetic correlates remain elusive.MethodsClinical-genetic and biomarker study of a first family with early- and late-onset AD associated with a nonsense ADAM10 mutation (p.Tyr167*). CSF analysis included AD core biomarkers, as well as Western blot of ADAM10 species and sAPPα and sAPPβ peptides. We evaluate variant’s pathogenicity, pattern of segregation, and further screened for the p.Tyr167* mutation in 197 familial AD cases from the same cohort, 200 controls from the same background, and 274 AD cases from an independent Spanish cohort.ResultsThe mutation was absent from public databases and segregated with the disease. CSF Aβ42, total tau, and phosphorylated tau of affected siblings were consistent with AD. The predicted haploinsufficiency effect of the nonsense mutation was supported by (a) ADAM10 isoforms in CSF decreased around 50% and (b) 70% reduction of CSF sAPPα peptide, both compared to controls, while sAPPβ levels remained unchanged. Interestingly, sporadic AD cases had a similar decrease in CSF ADAM10 levels to that of mutants, though their sAPPα and sAPPβ levels resembled those of controls. Therefore, a decreased sAPPα/sAPPβ ratio was an exclusive feature of mutant ADAM10 siblings. The p.Tyr167* mutation was not found in any of the other AD cases or controls screened.ConclusionsThis family illustrates the role of ADAM10 in the amyloidogenic process and the clinical development of the disease. Similarities between clinical and biomarker findings suggest that this family could represent a genetic model for sporadic late-onset AD due to age-related downregulation of α-secretase. This report encourages future research on ADAM10 enhancers.

Association of ADAM10 gene variants with sporadic Parkinson's disease in Chinese Han population

Objective: Parkinson's disease (PD) is the second-most common neurodegenerative disease in the world. Genetic factors play important role in familial and sporadic PD. Recently, rs653765 and rs514049 of ADAM10 gene variants were reported to be associated with Alzheimer disease (AD) in Caucasian population. However, the role of these variants in the pathogenesis of PD is unknown. Hence, to investigate the association between ADAM10 variants (rs653765 and rs514049) and PD susceptibility, we conducted a case-control study.

Iloprost affects in vitro maturation and developmental competence of bovine oocytes

Prostacyclin (PGI2) is synthesised in oviductal fluid and enhance the embryo development during the preimplantation period. The objective of the present study was to determine the effect of an analogue of prostacyclin (iloprost) on the in vitro maturation (IVM) and the developmental competence of bovine oocytes. Cumulus oocyte complexes (COCs) were cultured in maturation medium with iloprost (0.5 μM) for 24 h. We found that iloprost assisted maturation rates and cumulus cell expansion of bovine oocytes, and it increased the mRNA expression of genes related to cumulus expansion: ADAM17, AREG, and TNFAIP6 and cathepsin genes (CTSK and CTSS). Moreover, iloprost reduced the occurrence of apoptosis in COCs and promoted an antiapoptotic balance in the transcription of genes involved in apoptosis (BAX and BCL2). COCs treatment with iloprost during IVM also reduced intracellular reactive oxygen species (ROS) levels, while glutathione (GSH) levels and the mRNA expression of antioxidant genes CAT and GPx4 were markedly increased. We also showed that an analogue of PGI2 influenced the mitochondrial status via distribution rates of mitochondria and mitochondrial membrane potential in oocytes. Although, iloprost-enhanced maturation had no direct effect on number of embryos cleaved, it increased blastocyst rates of bovine embryos as well as proportion of expanded blastocysts. These results indicate that the supplementation of maturation medium with iloprost is beneficial for the maturation efficiency and developmental competence of bovine oocytes.

MiR-18a Inhibits BMP4 and HIF-1α Normalizing Brain Arteriovenous Malformations.

Brain arteriovenous malformations (AVMs) are abnormal tangles of vessels where arteries and veins directly connect without intervening capillary nets, increasing the risk of intracerebral hemorrhage and stroke. Current treatments are highly invasive and often not feasible. Thus, effective noninvasive treatments are needed. We previously showed that AVM-brain endothelial cells (BECs) secreted higher VEGF (vascular endothelial growth factor) and lower TSP-1 (thrombospondin-1) levels than control BEC; and that microRNA-18a (miR-18a) normalized AVM-BEC function and phenotype, although its mechanism remained unclear. To elucidate the mechanism of action and potential clinical application of miR-18a as an effective noninvasive treatment to selectively restore the phenotype and functionality of AVM vasculature. The molecular pathways affected by miR-18a in patient-derived BECs and AVM-BECs were determined by Western blot, RT-qPCR (quantitative reverse transcription polymerase chain reaction), ELISA, co-IP, immunostaining, knockdown and overexpression studies, flow cytometry, and luciferase reporter assays. miR-18a was shown to increase TSP-1 and decrease VEGF by reducing PAI-1 (plasminogen activator inhibitor-1/SERPINE1) levels. Furthermore, miR-18a decreased the expression of BMP4 (bone morphogenetic protein 4) and HIF-1α (hypoxia-inducible factor 1α), blocking the BMP4/ALK (activin-like kinase) 2/ALK1/ALK5 and Notch signaling pathways. As determined by Boyden chamber assays, miR-18a also reduced the abnormal AVM-BEC invasiveness, which correlated with a decrease in MMP2 (matrix metalloproteinase 2), MMP9, and ADAM10 (ADAM metallopeptidase domain 10) levels. In vivo pharmacokinetic studies showed that miR-18a reaches the brain following intravenous and intranasal administration. Intranasal co-delivery of miR-18a and NEO100, a good manufacturing practices-quality form of perillyl alcohol, improved the pharmacokinetic profile of miR-18a in the brain without affecting its pharmacological properties. Ultra-high-resolution computed tomography angiography and immunostaining studies in an Mgp-/- AVM mouse model showed that miR-18a decreased abnormal cerebral vasculature and restored the functionality of the bone marrow, lungs, spleen, and liver. miR-18a may have significant clinical value in preventing, reducing, and potentially reversing AVM.

Negatively charged amino acids in the stalk region of membrane proteins reduce ectodomain shedding

Ectodomain shedding is a post-translational modification mechanism by which the entire extracellular domain of membrane proteins is liberated through juxtamembrane processing. Because shedding rapidly and irreversibly alters the characteristics of cells, this process is properly regulated. However, the molecular mechanisms governing the propensity of membrane proteins to shedding are largely unknown. Here, we present evidence that negatively charged amino acids within the stalk region, an unstructured juxtamembrane region at which shedding occurs, contribute to shedding susceptibility. We show that two activated leukocyte cell adhesion molecule (ALCAM) protein variants produced by alternative splicing have different susceptibilities to ADAM metallopeptidase domain 17 (ADAM17)-mediated shedding. Of note, the inclusion of a stalk region encoded by a 39-bp-long alternative exon conferred shedding resistance. We found that this alternative exon encodes a large proportion of negatively charged amino acids, which we demonstrate are indispensable for conferring the shedding resistance. We also show that the introduction of negatively charged amino acids into the stalk region of shedding-susceptible ALCAM variant protein attenuates its shedding. Furthermore, we observed that negatively charged amino acids residing in the stalk region of Erb-B2 receptor tyrosine kinase 4 (ERBB4) are indispensable for its shedding resistance. Collectively, our results indicate that negatively charged amino acids within the stalk region interfere with the shedding of multiple membrane proteins. We conclude that the composition of the stalk region determines the shedding susceptibility of membrane proteins.