Biochemical and Biophysical Research Communications
Regular ArticleDifferential Expression of MammalianTRPHomologues across Tissues and Cell Lines
Abstract
Mammalian homologues of theDrosophila trpgene have been invoked as the structural basis for the currents associated with capacitative Ca2+entry (CCE) in many cell types.Trphomologues are members of a large protein family that may associate as channel subunits providing an explanation for the functional diversity of store-operated channels observed in these cells. However, there is little information as to which of these genes are co-expressed at the cellular level. We have examined the tissue specific expression of five mammaliantrpgenes and determined which are co-expressed in five different cell lines. The results show tissue- and cell-specific co-expression of multipletrpforms. This implies that the subunit composition of a particular CCE channel may vary depending on the cell type.
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Amphetamines abuse and depression: Focus on TRPC channels
2023, Experimental NeurologyAmphetamines, such as amphetamine (AMPH), methamphetamine (METH) and 3,4-methylenedioxymethamphetamine (MDMA), are the psychotropic substances widely abused in the world. Amphetamines abuse can damage dopaminergic and serotonin neurons and cause neuroinflammation and neurotoxicity. Neuropsychiatric disorders induced by amphetamines abuse include depression, anxiety, auditory hallucinations, mania, and cognitive disorders, of which depression has a higher incidence. Transient receptor potential (TRP) channels can regulate the inflow and outflow of Ca2+. In TRP family, transient receptor potential canonical (TRPC) channels are closely associated with the development of some neurological diseases, such as Parkinson's disease and Alzheimer's disease. However, the correlation between TRPC channels and depression and the specific mechanism of TRPC channels in depression still haven't been fully clarified. This review elaborates the pathophysiological mechanisms of depression induced by amphetamines abuse, the functions of TRPC channels in the nervous system, and the possible correlation between TRPC channels and depression induced by amphetamines abuse, which would provide the theoretical basis for the development of the novel and effective therapeutic drugs for amphetamines abuse-induced depression.
During myogenesis, a long splice variant of STIM1, called STIM1L is getting expressed, while the level of STIM1 remains constant. Previous work demonstrated that STIM1L is more efficient in eliciting store-operated Ca2+ entry (SOCE), but no current analysis of the channel(s) activated by this new STIM1L isoform was performed until now. In this study, we investigate the ionic channel(s) activated by STIM1L and whether differences exist between the two STIM1 isoforms, using HEK-293 T cells as a model system. Our data show that STIM1 and STIM1L activate Orai1 channel but also the endogenously expressed TRPC1. The channel activation occurs in two steps, with first Orai1 activation followed, in a subset of cells, by TRPC1 opening. Remarkably, STIM1L more frequently activates TRPC1 and preferentially interacts with TRPC1. In low intracellular Ca2+ buffering condition, the frequency of TRPC1 opening increases significantly, strongly suggesting a Ca2+-dependent channel activation. The ability of STIM1L to open Orai1 appears decreased compared to STIM1, which might be explained by its stronger propensity towards TRPC1. Indeed, increasing the amount of STIM1L results in an enhanced Orai1 current. The role of endogenous TRPC1 in STIM1- and STIM1L-induced SOCE was confirmed by Ca2+ imaging experiments. Overall, our findings provide a detailed analysis of the channels activated by both STIM1 isoforms, revealing that STIM1L is more prone to open TRPC1, which might explain the larger SOCE elicited by this isoform.
Endogenous TRPC channels mediate Ca<sup>2+</sup> signals and trigeminal synaptic plasticity induced by mGluR5
2019, Life SciencesMetabotropic glutamate receptor 5 (mGluR5), a member of group I mGluR, exerts its effect via elevation of intracellular Ca2+ level. We here characterized Ca2+ signals in the tsA201 cells transfected with mGluR5 and investigated the role of passages for mGluR5-induced Ca2+ signals in synaptic plasticity.
Using a genetically encoded Ca2+ indicator, GCamp2, Ca2+ signals were reliably induced by bath application of (S)-3,5-dihydroxyphenylglycine, the group I mGluR agonist, in the tsA201 cells transfected with mGluR5. Using whole-cell recordings in the substantia gelatinosa (SG) neurons of the spinal trigeminal subnucleus caudalis (Vc), excitatory postsynaptic currents were recorded by stimulating the trigeminal tract.
Ca2+ signals were mediated by “classical” or “canonical” transient receptor potential (TRPC) channels, particularly TRPC1/3/4/6, but not TRPC5, naturally existing in the tsA201 cells. Interestingly, the induction of Ca2+ signals was independent of the phospholipase C signaling pathway; instead, it critically involves the cyclic adenosine diphosphate ribose/ryanodine receptor-dependent signaling pathway and only partially protein kinase C. On the other hand, both TRPC3 and TRPC4 mediated mGluR1/5-induced long-lasting potentiation of excitatory synaptic transmission from the trigeminal primary afferents to the SG neurons of the Vc.
This study demonstrates that endogenous TRPC channels contribute to mGluR5-induced Ca2+ signals in tsA201 cells and synaptic plasticity at excitatory synapses.
Transient receptor potential (TRP) channels play important functional roles in the signal transduction machinery of hormone-secreting cells and have recently been implicated in reproductive physiology. While expression studies have demonstrated TRP channel expression at all levels of the hypothalamic–pituitary–gonadal (hpg) axis, functional details about TRP channel action at the level of the individual cells controlling reproduction are just beginning to emerge. Canonical TRP (TRPC) channels are prominently expressed in the reproductive center of the neuroendocrine brain, i.e. in kisspeptin and gonadotropin-releasing hormone (GnRH) neurons. Kisspeptin neurons are depolarized by leptin via activation of TRPC channels and kisspeptin depolarizes GnRH neurons through TRPC4 activation. Recent studies have functionally identified TRPC channels also in gonadotrope cells in the anterior pituitary gland, which secrete gonadotropins in response to GnRH and thus regulate gonadal function. TRP channel expression in these cells exhibits remarkable plasticity and depends on the hormonal status of the animal. Subsequent functional analyses have demonstrated that TRPC5 in gonadotropes contributes to depolarization of the plasma membrane upon GnRH stimulation and increases the intracellular Ca2+ concentration via its own Ca2+ permeability and via the activation of voltage-gated Ca2+ channels. However, conditional gene targeting experiments will be needed to unambiguously dissect the physiological role of TRPC channels in the different cell types of the reproductive axis in vivo.
Effector Roles of IgE Antibodies: Targeting Allergen to the High-Affinity IgE Receptor for FcεRI-Dependent Signaling and Antigen Presentation
2023, Inflammatory Mechanisms in Allergic DiseasesTransient receptor potential channel 6 in human skeletal muscle fibers: Investigation in fresh and conserved tissue samples
2022, Biomedical Reports