Constitutive degradation of IκBα in human T lymphocytes is mediated by calpain

BACKGROUND: Activation-induced induction of transcription factor NFκB in T lymphocytes is regulated by its inhibitor IκBα. NFκB activation has been demonstrated to occur either by phosphorylation on serine residues 32 and 36 of the inhibitor, IκBα, followed by ubiquitination and degradation of the inhibitor by the 26S proteasome, or by a proteasome-independent mechanism involving tyrosine phosphorylation, but not degradation. However, the mechanism underlying constitutive regulation of the levels of the inhibitor, IκB, in primary human T lymphocytes, remains to be fully delineated. RESULTS: We demonstrate here, the involvement of a proteasome-independent pathway for constitutive regulation of IκBα levels in primary human T lymphocytes. Pretreatment with a cell permeable calpain inhibitor, E64D, but not with a proteasome specific inhibitor, lactacystin, blocks stimulus-independent IκBα degradation in primary human T cells. However, E64D pre-treatment fails to impact on IκBα levels following stimulation with either TNFα or pervanadate. Other isoforms of the inhibitor, IκBβ, and IκBγ, appear not to be subject to a similar ligand-independent regulation. Unlike the previously reported decline in ligand-induced degradation of IκBα in T cells from the elderly, constitutive degradation does not exhibit an age-associated decline, demonstrating proteasome-independent regulation of the activity. CONCLUSION: Our studies support a role for an E64D sensitive protease in regulating constitutive levels of IκBα in T cells, independent of the involvement of the 26S proteasome, and suggests a biological role for constitutive degradation of IκBα in T cells

Mid-shaft clavicle fractures-factors influencing the clinical outcome after plate osteosynthesis

Background: Clavicle fractures constitute 5-10% of all fractures with. These fracture result from accidental fall, sports injuries or road traffic accidents The location and fracture pattern are important as it decides treatment and outcome. Our study is aimed to assess the various factors like: fracture pattern, type of implant used, and plate positioning and assessing their influence on clinical outcome.Methods: It was a prospective case-study. The study was done in department of orthopaedics, Government Villupuram Medical College Hospital Villupuram between December 2017 and December 2019. Those patients in whom there was indication for surgical management, and who were willing for surgery were admitted. Plate osteosynthesis was done using anatomical locking plate, recon plate, tubular plate. Post operative rehabilitation done. Functional and radiological assessment done at regular interval till fracture union.Results: All 32 patients had good union. Mean interval for fracture union was 4 months. 2 cases had implant failure, for which implant exit was done without any complication.Conclusions: Anatomical locking plate prove to be the ideal implant for management of mid shaft clavicle fracture. Failure by mechanical mode can be prevented by using lag screws and avoiding fracture spanning. Biological mode of failure can be prevented by guarded post operative rehabilitation in comminuted fractures

Anthocyanin, Lutein, Polyphenol Contents and Antioxidant Activity of Black, Red and White Pigmented Rice Varieties

Colour rice varieties are rich in antioxidants and functional based properties such as anthocyanin, lutein and phenolic compounds. In this experiment, two of red pigmented (TPS-1and TKM-9), one white (glutinous rice) and black pigmented rice varieties are cultivated from India were analysed to determine their antioxidants and nutrition based functional properties. Based on the result, the anthocyanin content was very high on black rice than other variety contents up to 244.45 mg/100 g. Polyphenol compound were varied significantly within the compared varieties. Highest polyphenol compound content (463.05 mg/100 g) was found in the black rice and also showed rich antioxidant properties. Obviously, black rice rich source of lutein compound was also higher than other varieties where under the experimental condition. DPPH (Determination of 2, 20-diphenyl-1picrylhydrazyl radical scavenging ability) scavenging capacity starting from 69.46% to 76.4% ranged to level of remain DPPH

Altered regulation of CXCR4 expression during aging contributes to increased CXCL12-dependent chemotactic migration of CD4(+) T cells.

Chemokine-dependent migration of T lymphocytes assures recirculation of na\uefve T cells to secondary lymphoid organs and tissue-specific trafficking of memory-effector T cells. Previous studies carried out in rodents have demonstrated age-associated modulation of the expression of chemokine receptors such as CXCR4 and CCR5; however, little is known about the molecular mechanisms that regulate receptor expression and turnover in T cells, during advancing age in humans. Our recent results demonstrating increased chemotactic migration in response to CXCL12 in CD4(+) T cells obtained from the elderly, as compared to those from young donors, led us to hypothesize that increase in surface expression, because of altered endocytic regulation of CXCR4 on T cells during aging, might be directly responsible for increased migration toward CXCL12. Studies presented here demonstrate a significant increase in the surface expression of CXCR4 in CD4(+) T cells from elderly human donors, relative to those from the young. Additionally, CXCL12-mediated endocytosis of CXCR4 was differentially regulated during aging, which could be attributed to alterations in the ubiquitination of CXCR4. Thus, altered ubiquitination of CXCR4 may contribute to the increased surface expression and enhanced T-cell migration to chemotactic stimuli in the elderly

Impairment of non-muscle myosin IIA in human CD4+ T cells contributes to functional deficits in the elderly.

Physiological aging imposes significant alterations in the repertoire of T cells and all associated functions. Although several studies have reported defects upon antigen-induced activation of T cells during aging, the molecular mechanisms that control T-cell receptor (TCR) downmodulation remain to be fully defined. While previous studies have assessed the role of F-actin in regulating activation-induced TCR internalization, few have delineated the roles of motor proteins, such as non-muscle myosin IIA (NMMIIA). In this study, we describe a series of experiments supporting the hypothesis that effective TCR downmodulation requires not only efficient reorganization of the actin cytoskeleton, but also functional NMMIIA. For the first time, we show that CD4(+) T cells from elderly human donors have dysfunctional NMMIIA that contributes to delaying activation-induced TCR internalization and impairing calcium mobilization. Additionally, our results demonstrate that chemical inhibition of NMMIIA in CD4(+) T cells from young donors also results in complete abrogation of TCR internalization, strongly supporting the fundamental role of NMMIIA in modulating this event. Recent observations that the generation of an efficient T-cell response requires migration prompted us to investigate whether NMMIIA also plays a regulatory role in CD4(+) T-cell migration. We show that chemical inhibition of NMMIIA downmodulates chemotactic migration in CD4(+) T cells from both young and elderly donors. Together, these data demonstrate a significant contribution of dysfunctional NMMIIA to TCR-mediated functional defects during agin

Thermal Conductivity Improvement in Carbon Nanoparticle Doped PAO Oil: An Experimental Study

The present work involves a study on the thermal conductivity of nanoparticle-oil suspensions for three types of nanoparticles, namely, carbon nanotubes(CNTs), exfoliated graphite (EXG), and heat treated nanofibers (HTT) with PAO oil as the base fluid. To accomplish the above task, an experimental analysis is performed using a modern light flash technique (LFA 447) for measuring the thermal conductivity of the three types of nanofluids, for different loading of nanoparticles. The experimental results show a similar trend as observed in literature for nanofluids with a maximum enhancement of approximately 161% obtained for the CNT-PAO oil suspension. The overall percent enhancements for different volume fractions of the nanoparticles are highest for the CNT-based nanofluid, followed by the EXG and the HTT. The findings from this study for the three different types of carbon nanoparticles can have great potential in the field of thermal management

A quest for understanding

When I tried to introspect as to why I chose Science as a career path, it was truly the very first time that I had delved into my past as a student, trying to search through my memory bank for that one special moment in my life that was a turning point. However, while it became clear that no one specific event set the stage for my future in science, it was, I think, a series of unrelated events that shaped my thinking that ultimately led me down this adventurous path, that I so cherish today

An organ culture system to model early degenerative changes of the intervertebral disc

ABSTRACT: INTRODUCTION: Back pain, a significant source of morbidity in our society, is related to the degenerative changes of the intervertebral disc. At present, the treatment of disc disease consists of therapies that are aimed at symptomatic relief. This shortcoming stems in large part from our lack of understanding of the biochemical and molecular events that drive the disease process. The goal of this study is to develop a model of early disc degeneration using an organ culture. This approach is based on our previous studies that indicate that organ culture closely models molecular events that occur in vivo in an ex vivo setting. METHODS: To mimic a degenerative insult, discs were cultured under low oxygen tension in the presence of TNF-α, IL-1β and serum limiting conditions. RESULTS: Treatment resulted in compromised cell survival and changes in cellular morphology reminiscent of degeneration. There was strong suppression in the expression of matrix proteins including collagen types 1, 2, 6 and 9, proteoglycans, aggrecan and fibromodulin. Moreover, a strong induction in expression of catabolic matrix metalloproteinases (MMP) 3, 9 and 13 with a concomitant increase in aggrecan degradation was seen. An inductive effect on NGF expression was also noticed. Although similar, nucleus pulposus and annulus fibrosus tissues showed some differences in their response to the treatment. CONCLUSIONS: Results of this study show that perturbations in microenvironmental factors result in anatomical and gene expression change within the intervertebral disc that may ultimately compromise cell function and induce pathological deficits. This system would be a valuable screening tool to investigate interventional strategies aimed at restoring disc cell function

Immune Function and Muscle Adaptations to Resistance exercise in Older Adults: Study Protocol for a Randomized Controlled Trial of a Nutritional Supplement

BACKGROUND: Immune function may influence the ability of older adults to maintain or improve muscle mass, strength, and function during aging. Thus, nutritional supplementation that supports the immune system could complement resistance exercise as an intervention for age-associated muscle loss. The current study will determine the relationship between immune function and exercise training outcomes for older adults who consume a nutritional supplement or placebo during resistance training and post-training follow-up. The supplement was chosen due to evidence suggesting its ingredients [arginine (Arg), glutamine (Gln), and β-hydroxy β-methylbutyrate (HMB)] can improve immune function, promote muscle growth, and counteract muscle loss. METHODS/DESIGN: Veterans (age 60 to 80 yrs, N = 50) of the United States military will participate in a randomized double-blind placebo-controlled trial of consumption of a nutritional supplement or placebo during completion of three study objectives: 1) determine if 2 weeks of supplementation improve immune function measured as the response to vaccination and systemic and cellular responses to acute resistance exercise; 2) determine if supplementation during 36 sessions of resistance training boosts gains in muscle size, strength, and function; and 3) determine if continued supplementation for 26 weeks post-training promotes retention of training-induced gains in muscle size, strength, and function. Analyses of the results for these objectives will determine the relationship between immune function and the training outcomes. Participants will undergo nine blood draws and five muscle (vastus lateralis) biopsies so that the effects of the supplement on immune function and the systemic and cellular responses to exercise can be measured. DISCUSSION: Exercise has known effects on immune function. However, the study will attempt to modulate immune function using a nutritional supplement and determine the effects on training outcomes. The study will also examine post-training benefit retention, an important issue for older adults, usually omitted from exercise studies. The study will potentially advance our understanding of the mechanisms of muscle gain and loss in older adults, but more importantly, a nutritional intervention will be evaluated as a complement to exercise for supporting muscle health during aging. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02261961, registration date 10 June 2014, recruitment active