Biology subjects

Majhi, R. K.

Publications and source records attributed to Majhi, R. K..

3 recordsLinked to original sources

bioRxiv2020

Differential expression and localization of thermosensitive Transient Receptor Potential Vanilloid (TRPV) channels in the mature sperm of white pekin duck (Anas platyrhynchos)

Sperm cells have the ability of precise chemotactic and thermotactic movement which is crucial for fertilization, yet the key molecules involved in the detection of different chemical and physical stimuli and guide the sperm cells for proper navigation are not known. This aspect is more complex as each species have their own reproductive identity. Never-the-less, Ca2+-signaling and thus a series of Ca2+-channels seem to coordinate in order to regulate different functions mediated by sperm cells. However, such aspects are controlled by different Ca2+ channels and have species-specific differences. In this work we explored if TRPV channels are endogenously expressed in the mature spermatozoa obtained from avian species. We have used the sperm cells of white pekin duck (Anas platyrhynchos) as a representative avian species to explore the endogenous expression and localization of different TRPV channels. Western blot analysis (WB), flow cytometry, confocal imaging and super resolution imaging was performed for the characterization. Our results strongly suggest the expression and distinct localization of different TRPV channels in the sperm cells. All these TRPV channels are mainly absent in the head region. Only TRPV3 and TRPV4 are sparsely present in the neck region enriched with mitochondria. All these channels (TRPV1-6) are present in the tail region. The differential localization of TRPVs in duck sperm indicate their respective functions relevant in fertilization process of avian sperm. These findings may also have commercial importance in poultry production, cryopreservation of sperm as well as conservation of endangered species through artificial insemination.

cell biology↗

bioRxiv2019

Transient Receptor Potential Ankyrin1 channel is endogenously expressed in T cells and regulates immune functions

Transient Receptor Potential channel subfamily A member 1 (TRPA1) is a non selective cationic channel, identified initially as a cold sensory receptor. TRPA1 responds to diverse exogenous and endogenous stimuli associated with pain and inflammation. However, the role of TRPA1 towards T cell responses remains scanty. In this work, we explored the endogenous expression of TRPA1 in T cells. By RT-PCR we confirmed the expression of TRPA1 in T cell at RNA level. Using confocal microscopy as well as flow cytometry, we demonstrated that TRPA1 is endogenously expressed in primary murine splenic T cells as well as in primary human T cells. The endogenous expression of TRPA1 is confirmed by using another antibody. TRPA1 was primarily located at the cell surface. TRPA1-specific activator namely AITC increases intracellular Ca2+-levels while two different inhibitors namely A-967079 as well as HC-030031 reduce intracellular Ca2+-levels in T cells. Such Ca2+-influx can also be influenced by chelation of intracellular Ca2+ as well as extracellular Ca2+. TRPA1 expression was found to be increased during CD3/CD28 (TCR) or ConA driven stimulation in T cells. TRPA1-specific inhibitor treatment prevented induction of CD25, CD69 in ConA/TCR stimulated T cells and secretion of cytokines like TNF, IFN-{gamma} and IL-2 suggesting that endogenous activity of TRPA1 may be involved in T cell activation. Collectively these results may have implication in T cell-mediated responses and possible role of TRPA1 in immunological disorders.

immunology↗

bioRxiv2018

TRPV4 interacts with mitochondrial proteins and acts as a mitochondrial structure-function regulator

TRPV4 has been linked with the development of sensory defects, neuropathic pain, neurodegenerative disorders such as Charcot Marie Tooth disease and various muscular dystrophies. In all these cases mitochondrial abnormalities were tagged as cellular hallmarks and such abnormalities have been reported as key factor for the pathophysiological conditions. Mitochondria also have the unique ability to sense and regulate their own temperature. Here, we demonstrate that TRPV4, a thermosensitive ion channels, localizes to a subpopulation of mitochondria in various cell lines, in primary cells and also in sperm cells. Improper expression and/or function of TRPV4 induce several mitochondrial abnormalities such as low oxidative potential, high Ca2+-influx and changes in electron transport chain functions. TRPV4 is also involved in regulation of mitochondrial morphology, smoothness, and fusion-fission events. The C-terminal cytoplasmic region of TRPV4 can localize it to mitochondria and interacts with mitochondrial proteins including Hsp60, Mfn1 and Mfn2. Regulation of mitochondria by TRPV4 may contribute to previously uncharacterized mitochondria-specific functions observed in various cell types. This discovery may help to link TRPV4-mediated channelopathies with mitochondria-mediated diseases.

cell biology↗