Effects of insulin-like growth factor 1 on glutathione S-transferases and thioredoxin in growth hormone receptor knockout mice

Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) have been shown to affect processes involved in cellular stress defense, aging, and longevity. This study was designed to identify possible mechanisms of a disrupted GH signaling pathway on stress resistance using growth hormone receptor knockout (GHRKO) mice. GHRKO mice are GH resistant due to the targeted disruption of the GH receptor/binding protein gene, thus preventing GH from binding and exerting its downstream effects. These mice have very low circulating IGF-1 levels and high GH levels, are obese yet insulin sensitive, and live longer than their wild-type controls. Wild-type or GHRKO mice were treated with saline or IGF-1 (WT saline, GHRKO saline, GHRKO IGF-1) two times daily for 7 days. Glutathione S-transferase (GST) activities, proteins, and gene expression were determined. Liver mitochondrial GSTA1, GSTA3, and GSTZ1 proteins were significantly higher in GHRKO when compared to those of WT mice. The 4-hydroxynonenal (4-HNE) GST activity was upregulated in GHRKO mice and was suppressed after IGF-1 administration. Interestingly, thioredoxin (Trx)1, Trx2, thioredoxin reductase (TrxR)1, and TrxR2 messenger RNA (mRNA) levels were significantly higher in the GHRKO as compared to WT mice, and IGF-1 treatment suppressed the expression of each. We also found that glutaredoxin (Grx)2 mRNA and cytosolic Grx activity were higher in GHRKO mice. These results suggest that the detoxification and stress response mechanisms in GHRKO mice are contributed in part by the circulating level of IGF-1.     

Molecular functions of anoctamin 6 (TMEM16F): a chloride channel,cation channel,or phospholipid scramblase?

Anoctamin 6 (Ano6; TMEM16F gene) is a ubiquitous protein; the expression of which is defective in patients with Scott syndrome, an inherited bleeding disorder based on defective scrambling of plasma membrane phospholipids. For Ano6, quite diverse functions have been described: (1) it can form an outwardly rectifying, Ca²⁺-dependent and a volume-regulated Cl^? channel; (2) it was claimed to be a Ca²⁺-regulated nonselective cation channel permeable for Ca²⁺; (3) it was shown to be essential for Ca²⁺-mediated scrambling of membrane phospholipids; and (4) it can regulate cell blebbing and microparticle shedding. Deficiency of Ano6 in blood cells from Scott patients or Ano6 null mice appears to affect all of these cell responses. Furthermore, Ano6 deficiency in mice impairs the mineralization of osteoblasts, resulting in reduced skeletal development. These diverse results have been obtained under different experimental conditions, which may explain some of the contradictions. This review therefore aims to summarize the currently available information on the diverse roles of Ano6 and tries to clear up some of the existing controversies.     

Assessing costs of a hypertension management program: An application of the HEARTS costing tool in a program planning workshop in Thailand

The HEARTS technical package, a part of the Global Hearts Initiative to improve cardiovascular health globally, is a strategic approach for cardiovascular disease prevention and control at the primary care level. To support the evaluation of costs associated with HEARTS program components, a costing tool was developed to evaluate the incremental cost of program implementation. This report documents an application of the HEARTS costing tool during a costing workshop prior to the initiation of a HEARTS pilot program in Thailand's Phothong District, 2019‐2020. During the workshop, a mock exercise was conducted to estimate the expected costs of the pilot study. The workshop application of the tool underscored its applicability to the HEARTS program planning process by identifying cost drivers associated with individual program elements. It further illustrated that by supporting disaggregation of costs into fixed and variable categories, the tool can inform the scalability of pilot projects to larger populations. Lessons learned during the initial development and application of the costing tool can inform future HEARTS evaluation efforts.     

Plasma extracellular vesicle microRNA-491-5p as diagnostic and prognostic marker for head and neck squamous cell carcinoma

Poor survival of patients with locally advanced head and neck squamous cell carcinoma (LA-HNSCC) is partly due to early diagnosis difficulties and the lack of reliable biomarkers for predicting treatment outcomes. In the discovery cohort, plasma-derived extracellular vesicles (EVs) from LA-HNSCC patients (n = 48) and healthy volunteers (n = 12) were used for profiling for microRNA (miRNA) expression by NanoString analysis. Ten EV-associated miRNAs were differentially expressed between LA-HNSCC patients and healthy volunteers. Subsequently, the results were validated in the individual discovery and additional cases (HNSCC, n = 73; control, n = 20) by quantitative RT-PCR. Among 10 EV-miRNAs, four (miR-27b-3p, miR-491-5p, miR-1910-5p, and miR-630) were significantly dysregulated in LA-HNSCC patients (n = 73) compared with healthy volunteers (n = 20). The miRNA prediction models were developed to discriminate HNSCC patients from healthy volunteers. The model using miR-491-5p was selected as a diagnostic biomarker for LA-HNSCC with a sensitivity and specificity of 46.6% and 100%, respectively (P < .001). The dynamic changes of miRNA model score (ΔmiRNAs) were determined using scores pre- and postdefinitive treatment to further investigate the prognostic value of miRNA prediction models. The univariate and multivariate analyses indicated that ΔmiR-491-5p was the most powerful and independent prognostic indicator for overall survival (hazard ratio [HR] 5.66, 95% confidence interval, 1.77-18.01; P = .003) and disease-free survival (HR 2.82, 95% CI, 1.13-7.05; P = .027) of HNSCC patients. In summary, the miR-491-5p prediction model could serve as a blood-based diagnostic marker for LA-HNSCC. Moreover, ΔmiR-491-5p could be a potential monitoring prognostic marker to reflect the survival of HNSCC patients.     

Stromal Keratitis with Endophthalmitis Caused by Vittaforma Corneae in an Immunocompetent Patient: A Case Report

Purpose: To describe a case of microsporidial stromal keratitis with endophthalmitis in an immunocompetent patient.Methods: Case reportResults: A 58-year-old HIV-negative man presented with stromal keratitis in his right eye. The patient demonstrated subsequent vitritis, multifocal retinitis and arteritis, and macular edema with recurrent vitreous hemorrhage after therapeutic keratoplasty. Numerous microsporidial spores were detected in corneal tissues by modified trichrome stain. Both corneal tissues and vitreous sample of the affected eye showed positive results by polymerase chain reaction targeting the microsporidial small subunit rRNA gene whose sequences belonged to Vittaforma corneae. Post-keratoplasty and vitrectomy, his best-corrected visual acuity was hand motion due to pale optic disc.Conclusion: Endophthalmitis can be a consequence of microsporidial stromal keratitis in an immunocompetent host. Early recognition and prompt treatment should be considered in patients diagnosed with microsporidial keratitis presenting with mild vitritis, retinitis, and recurrent vitreous hemorrhage.     

Slc26a11 is prominently expressed in the brain and functions as a chloride channel: expression in Purkinje cells and stimulation of V H+-ATPase

SLC26A11 (human)/Slc26a11 (mouse), also known as kidney brain anion transporter (KBAT), is a member of the SLC26 anion transporter family and shows abundant mRNA expression in the brain. However, its exact cellular distribution and subcellular localization in the brain and its functional identity and possible physiological roles remain unknown. Expression and immunostaining studies demonstrated that Slc26a11 is abundantly expressed in the cerebellum, with a predominant expression in Purkinje cells. Lower expression levels were detected in hippocampus, olfactory bulb, cerebral cortex, and subcortical structures. Patch clamp studies in HEK293 cells transfected with mouse cDNA demonstrated that Slc26a11 can function as a chloride channel that is active under basal conditions and is not regulated by calcium, forskolin, or co-expression with cystic fibrosis transmembrane regulator. Single and double immunofluorescent labeling studies demonstrated the localization of vacuolar (V) H⁺-ATPase and Slc26a11 (KBAT) in the plasma membrane in Purkinje cells. Functional studies in HEK293 cells indicated that transfection with Slc26a11 stimulated acid transport via endogenous V H⁺-ATPase. We conclude that Slc26a11 (KBAT) is prominently distributed in output neurons of various subcortical and cortical structures in the central nervous system, with specific expression in Purkinje cells and that it may operate as a chloride channel regulating acid translocation by H⁺-ATPase across the plasma membrane and in intracellular compartments.