Receptor Potential Cation Channel Subfamily Research Articles

Relationship between ENaC Regulators and SARS-CoV-2 Virus Receptor (ACE2) Expression in Cultured Adult Human Fungiform (HBO) Taste Cells.

In addition to the α, β, and γ subunits of ENaC, human salt-sensing taste receptor cells (TRCs) also express the δ-subunit. At present, it is not clear if the expression and function of the ENaC δ-subunit in human salt-sensing TRCs is also modulated by the ENaC regulatory hormones and intracellular signaling effectors known to modulate salt responses in rodent TRCs. Here, we used molecular techniques to demonstrate that the G-protein-coupled estrogen receptor (GPER1), the transient receptor potential cation channel subfamily V member 1 (TRPV1), and components of the renin-angiotensin-aldosterone system (RAAS) are expressed in δ-ENaC-positive cultured adult human fungiform (HBO) taste cells. Our results suggest that RAAS components function in a complex with ENaC and TRPV1 to modulate salt sensing and thus salt intake in humans. Early, but often prolonged, symptoms of COVID-19 infection are the loss of taste, smell, and chemesthesis. The SARS-CoV-2 spike protein contains two subunits, S1 and S2. S1 contains a receptor-binding domain, which is responsible for recognizing and binding to the ACE2 receptor, a component of RAAS. Our results show that the binding of a mutated S1 protein to ACE2 decreases ACE2 expression in HBO cells. We hypothesize that changes in ACE2 receptor expression can alter the balance between the two major RAAS pathways, ACE1/Ang II/AT1R and ACE2/Ang-(1–7)/MASR1, leading to changes in ENaC expression and responses to NaCl in salt-sensing human fungiform taste cells.

In Vivo Inhibition of TRPC6 by SH045 Attenuates Renal Fibrosis in a New Zealand Obese (NZO) Mouse Model of Metabolic Syndrome.

Metabolic syndrome is a significant worldwide public health challenge and is inextricably linked to adverse renal and cardiovascular outcomes. The inhibition of the transient receptor potential cation channel subfamily C member 6 (TRPC6) has been found to ameliorate renal outcomes in the unilateral ureteral obstruction (UUO) of accelerated renal fibrosis. Therefore, the pharmacological inhibition of TPRC6 could be a promising therapeutic intervention in the progressive tubulo-interstitial fibrosis in hypertension and metabolic syndrome. In the present study, we hypothesized that the novel selective TRPC6 inhibitor SH045 (larixyl N-methylcarbamate) ameliorates UUO-accelerated renal fibrosis in a New Zealand obese (NZO) mouse model, which is a polygenic model of metabolic syndrome. The in vivo inhibition of TRPC6 by SH045 markedly decreased the mRNA expression of pro-fibrotic markers (Col1α1, Col3α1, Col4α1, Acta2, Ccn2, Fn1) and chemokines (Cxcl1, Ccl5, Ccr2) in UUO kidneys of NZO mice compared to kidneys of vehicle-treated animals. Renal expressions of intercellular adhesion molecule 1 (ICAM-1) and α-smooth muscle actin (α-SMA) were diminished in SH045- versus vehicle-treated UUO mice. Furthermore, renal inflammatory cell infiltration (F4/80+ and CD4+) and tubulointerstitial fibrosis (Sirius red and fibronectin staining) were ameliorated in SH045-treated NZO mice. We conclude that the pharmacological inhibition of TRPC6 might be a promising antifibrotic therapeutic method to treat progressive tubulo-interstitial fibrosis in hypertension and metabolic syndrome.

TRPM7 promotes lipopolysaccharide-induced inflammatory dysfunction in renal tubular epithelial cells.

BackgroundSepsis‐associated acute kidney injury (S‐AKI) has been reported to affect 30%–50% of all sepsis patients; this condition is associated with a notable fatality rate. Following lipopolysaccharide (LPS) stimulation, the expression of transient receptor potential cation channel subfamily M member 7 (TRPM7), a nonselective cation channel expressed by the renal tubular epithelial cells (RTECs) was found to be upregulated. We aimed to determine how TRPM7 functions in S‐AKI.MethodsTo establish an in vitro model of S‐AKI, RTECs were treated with LPS. The effect of TRPM7 knockdown on cell viability, lactate dehydrogenase (LDH) release, apoptosis, inflammation, and oxidative stress was studied. The binding site between Kruppel‐like factor 2 (KLF2) and TRPM7 was predicted using JASPAR. The influence of KLF2 on the regulatory roles of TRPM7 in cells, as well as the effect of their knockdown on the MAPK signaling pathway, was investigated.ResultsTRPM7 was upregulated in LPS‐treated cells, and knocking improved cell viability, reduced LDH levels, and minimized apoptosis, inflammation, and oxidative stress. KLF2 was shown to be associated with TRPM7 and its level decreased in LPS‐treated cells. KLF2 knockdown increased TRPM7 expression and reversed the effects of TRPM7 knockdown in LPS‐treated cells, including suppression of p38 MAPK, ERK1/2, and JNK activation.ConclusionTaken together, our results show that TRPM7 is negatively regulated by KLF2 and promotes LPS‐induced inflammatory dysfunction by activating the MAPK pathway in RTECs. The theoretical foundation for the prevention and management of S‐AKI is laid out in this article.

TRPM2 regulates autophagy to participate in hepatitis B virus replication.

Hepatitis B virus (HBV) affects over 300 million people across the world and is further associated with the self-digesting process of autophagy. Accordingly, the current study set out to explore the role of transient receptor potential cation channel subfamily M member 2 (TRPM2) in HBV replication. Firstly, Huh-7 cells were transfected with the pHBV1.3 plasmid to detect the expression patterns of TRPM2 and neutrophil cytosolic factor 1 (p47 phox), followed by evaluating the role of TRPM2 in autophagy and HBV replication and exploring the interaction between TRPM2 and p47 phox. Collaborative experiments were further designed to explore the role of p47 phox and autophagy in TRPM2 regulation of HBV replication, in addition to animal experimentation to validate the role of TRPM2/p47 phox axis in vivo. It was found that TRPM2 up-regulation was associated with HBV replication. On the other hand, silencing of TRPM2 inhibited HBV replication and autophagy in vitro and in vivo, as evidenced by reduced HBV DNA load, HBV mRNA, HBeAg and HBsAg, and diminished autophagic spot number, LC3 II/I ratio, Beclin-1 expressions and increased p62 expressions. Mechanistic experimentation illustrated that TRPM2 interacted with p47 phox and positively regulated p47 phox, such that p47 phox up-regulation or use of Rapamycin (autophagy activator) weakened the inhibitory role of silencing TRPM2. Collectively, our findings indicated that HBV infection promotes TRPM2 expression, and TRPM2 interacts with p47 phox to induce autophagy and facilitate HVB replication.

Regulation of Ca2+ for Cancer Cell Apoptosis through Photothermal Conjugated Nanoparticles.

Ca2+ overload is caused by the abnormal accumulation of Ca2+, which is a potential therapeutic strategy for inhibiting tumor growth. However, due to the limited intracellular Ca2+ concentration, its anticancer effect is non-significant. Herein, near-infrared (NIR)-responsive nanoparticles NPs-PCa (DPPC-DSPE-PEG2000-NH2@PDPP@CaO2@DOX) were designed and prepared to achieve photothermal trigger of Ca2+ release, thereby increasing intracellular Ca2+ content. Furthermore, the nanoparticles convert light to heat to activate the transient receptor potential cation channel subfamily V member 1 (TRPV1) ion channels, allowing external Ca2+ to flow into the cells, further increasing the Ca2+ concentration. NPs-PCa nanoparticles overcome the limitation of insufficient concentration by increasing Ca2+ in both internal and external approaches. Meanwhile, an imbalance of intracellular Ca2+ induces mitochondrial dysfunction and ultimately results in cancer cell death. This study provides an effective strategy for inhibiting breast cancer tumor growth by regulating Ca2+ concentration.

Engineering Saccharomyces cerevisiae for production of the capsaicinoid nonivamide

BackgroundCapsaicinoids are produced by plants in the Capsicum genus and are the main reason for the pungency of chili pepper fruits. They are strong agonists of TRPV1 (the transient receptor potential cation channel subfamily V member 1) and used as active ingredients in pharmaceuticals for the treatment of pain. The use of bioengineered microorganisms in a fermentation process may be an efficient route for their preparation, as well as for the discovery of (bio-)synthetic capsaicinoids with improved or novel bioactivities.ResultsSaccharomyces cerevisiae was engineered to over-express a selection of amide-forming N-acyltransferase and CoA-ligase enzyme cascades using a combinatorial gene assembly method, and was screened for nonivamide production from supplemented vanillylamine and nonanoic acid. Data from this work demonstrate that Tyramine N-hydroxycinnamoyl transferase from Capsicum annuum (CaAT) was most efficient for nonivamide formation in yeast, outcompeting the other candidates including AT3 (Pun1) from Capsicum spp. The CoA-ligase partner with highest activity from the ones evaluated here were from Petunia hybrida (PhCL) and Spingomonas sp. Ibu-2 (IpfF). A yeast strain expressing CaAT and IpfF produced 10.6 mg L−1 nonivamide in a controlled bioreactor setup, demonstrating nonivamide biosynthesis by S. cerevisiae for the first time.ConclusionsBaker’s yeast was engineered for production of nonivamide as a model capsaicinoid, by expressing N-acyltransferases and CoA-ligases of plant and bacterial origin. The constructed yeast platform holds potential for in vivo biocatalytic formation of capsaicinoids and could be a useful tool for the discovery of novel drugs.

Transient Receptor Potential Channels, Natriuretic Peptides, and Angiotensin Receptor-Neprilysin Inhibitors in Patients With Heart Failure.

Heart failure (HF) remains the leading cause of death, morbidity, and medical expenses worldwide. Treatments for HF with reduced ejection fraction have progressed in recent years; however, acute decompensated heart failure remains difficult to treat. The transient receptor potential (TRP) channel family plays roles in various cardiovascular diseases, responding to neurohormonal and mechanical load stimulation. Thus, TRP channels are promising targets for drug discovery, and many studies have evaluated the roles of TRP channels expressed on pain neurons. The natriuretic peptide (NP) family of proteins regulates blood volume, natriuresis, and vasodilation and can antagonize the renin-angiotensin-aldosterone system and participate in the pathogenesis of major cardiovascular diseases, such as HF, coronary atherosclerotic heart disease, and left ventricular hypertrophy. NPs are degraded by neprilysin, and the blood level of NPs has predictive value in the diagnosis and prognostic stratification of HF. In this review, we discuss the relationships between typical TRP family channels (e.g., transient receptor potential cation channel subfamily V member 1 andTRPV1, transient receptor potential cation channel subfamily C member 6) and the NP system (e.g., atrial NP, B-type NP, and C-type NP) and their respective roles in HF. We also discuss novel drugs introduced for the treatment of HF.

Angelica dahurica Extracts Attenuate CFA-Induced Inflammatory Pain via TRPV1 in Mice.

Angelica dahurica, belonging to the family Apiaceae, is a well-known herbal medicine. The roots of Angelica dahurica are commonly used for the treatment of headache, toothache, abscess, furunculosis, and acne. However, little is known about their analgesic molecular mechanism underlying pain relief. In this study, we used behavioral tests to assess the analgesic effect of the ADE (Angelica dahurica extracts) on CFA (complete Freund's adjuvant)-induced inflammatory pain mice models. TRPV1 (Transient Receptor Potential Cation Channel Subfamily V Member 1) protein activity in dorsal root ganglion (DRG) was assessed with a calcium imaging assay. TRPV1 expression was detected with western blot and immunohistochemistry. Then, we examined the constituents of ADE using combined ultra-performance liquid chromatography-quadrupole time-of-light mass spectrometry (UPLC/Q−TOF−MS). Our results showed that ADE effectively attenuated mechanical and thermal hypersensitivities in CFA-induced inflammatory pain model in mice. ADE also significantly reduced the activity and the protein expression of TRPV1 in DRG from CFA mice. Therefore, ADE might be an attractive and suitable analgesic agent for the management of chronic inflammatory pain.

Tranilast for advanced heart failure in patients with muscular dystrophy: a single-arm, open-label, multicenter study

BackgroundThe transient receptor potential cation channel subfamily V member 2 (TRPV2) is a stretch-sensitive calcium channel. TRPV2 overexpression in the sarcolemma of skeletal and cardiac myocytes causes calcium influx into the cytoplasm, which triggers myocyte degeneration. In animal models of cardiomyopathy and muscular dystrophy (MD), TRPV2 inhibition was effective against heart failure and motor function. Our previous pilot study showed that tranilast, a TRPV2 inhibitor, reduced brain natriuretic peptide (BNP) levels in two MD patients with advanced heart failure. Thus, this single-arm, open-label, multicenter study aimed to evaluate the safety and efficacy of tranilast for heart failure.MethodsThe study enrolled MD patients with advanced heart failure whose serum BNP levels were > 100 pg/mL despite receiving standard cardioprotective therapy. Tranilast was administered orally at 100 mg, thrice daily. The primary endpoint was the change in log (BNP) (Δlog [BNP]) at 6 months from baseline. The null hypothesis was determined based on a previous multicenter study of carvedilol results in a mean population Δlog (BNP) of 0.18. TRPV2 expression on peripheral blood mononuclear cell surface, cardiac events, total mortality, left ventricular fractional shortening, human atrial natriuretic peptide, cardiac troponin T, and creatine kinase, and pinch strength were also assessed.ResultsBecause of the poor general condition of many patients, only 18 of 34 patients were included and 13 patients could be treated according to the protocol throughout the 6-month period. However, there were no serious adverse events related to tranilast except diarrhea, a known adverse effect, and the drug was administered safely. TRPV2 expression on the mononuclear cell surface was elevated at baseline and reduced after treatment. Cardiac biomarkers such as BNP, human atrial natriuretic peptide, and fractional shortening remained stable, suggesting a protective effect against the progression of heart failure. In the per protocol set group, Δlog [BNP] was − 0.2 and significantly lower than that in the null hypothesis.ConclusionsTranilast is safe and effective in inhibiting TRPV2 expression, even in MD patients with advanced heart failure. Further trials are needed to evaluate the efficacy of tranilast in preventing myocardial damage, heart failure, motor impairment, and respiratory failure.Clinical trial registration The study was registered in the UMIN Clinical Trials Registry (UMIN-CTR: UMIN000031965, URL: http://www.umin.ac.jp/ctr/) [March 30, 2018] and the Japan Registry of Clinical Trials (jRCT, registration number: jRCTs031180038, URL: https://jrct.niph.go.jp/) [November 12, 2021]. Patient registration was started in December 19, 2018.

Bacteria‐Derived Hypoxanthine Accelerates Gastrointestinal Transit

Irritable bowel syndrome is a globally prevalent disorder categorized into constipation, diarrhea or mixed (IBS‐C, IBD‐D, IBS‐M) based on the predominant stool form/frequency. While the gut microbiome is recognized as an important factor underlying the pathophysiology of IBS, the specific mechanisms remain an area of active investigation. In our recent longitudinal multi‐omics study in IBS patients, we found bacteria‐derived hypoxanthine was significantly decreased in stool from IBS‐C patients. The aim of this study was to determine if IBS‐C relevant molecular pathways are affected by hypoxanthine. We hypothesized that hypoxanthine acts on enterochromaffin (EC) cells to stimulate serotonin (5‐HT) release, where 5‐HT is an important determinant of gastrointestinal (GI) transit time. We used Ca2+ imaging in QGP cells (EC model), T84 cells (colonocyte model), primary cells and organoids from NeuroD1‐cre;GCaMP5‐tdTomato mice [NeuroD1 is a marker for enteroendocrine cells (EECs) which express calcium indicator GCaMP in these mice] in the absence or presence of receptor antagonists, and in ex vivo colon preparations with intact innervation from E2aCre:GCaMP6s mice (GCaMP is expressed in neuronal and non‐neuronal cells), to test the effect of hypoxanthine. The physiologic relevance of hypoxanthine signaling was assessed by measuring whole gut transit time. We found hypoxanthine increased Ca2+ influx in QGP cells [using Cal520 (qualitative) and Fura‐2AM (quantitative)], primary EECs and EECs within organoids (previous research showed that the majority of these EECs are EC cells), but not in T84 cells. Hypoxanthine‐evoked Ca2+ response was absent in Ca2+‐free medium (n=6‐8, t‐test, P<0.0001), inhibited by Gαi/o‐GPCR antagonist (pertussis toxin; n=8‐14, t‐test, P<0.01)), Transient Receptor Potential Cation Channel Subfamily C Member 4 (TRPC4) antagonist (ML204; n=14‐15, t‐test, P<0.0001) and TRPC4 siRNA (n=5‐21, t‐test, P<0.01), and was accompanied by increased 5‐HT release (measured using 5‐HT biosensor). In ex vivo experiments, luminal application of hypoxanthine activated a subset of epithelial cells (likely EC cells) followed by subsets of neurons (latency to response onset, n=4, Mann‐Whitney, P<0.0001), as well as movement of the imaging field, which indicates smooth muscle contraction/relaxation. Our in vitro findings were confirmed by in vivo experiments showing that germ‐free mice colonized with hypoxanthine‐producing bacteria had faster whole gut transit and higher stool 5‐HT level compared to hypoxanthine‐consuming bacteria (n=7‐8, t‐test, P<0.05). In summary, hypoxanthine increases Ca2+ influx specifically in EC cells by activating a signaling cascade involving a Gαi/o‐GPCR and TRPC4 channels, which results in 5‐HT release. The delay in activation of myenteric neurons and motor activity suggests that EC cell 5‐HT release likely induces neurogenic motor patterns and may underlie the shorter GI transit time seen with increased bacterial hypoxanthine production. While the current empirically designed probiotics have proven ineffective in IBS, our findings will allow development of novel mechanism‐based probiotic therapies for IBS‐C using hypoxanthine‐producing bacteria.

Exploring cutaneous neuro-immune networks during helminth infection

Abstract Sensory nociceptive neurons serve important roles in regulation of cutaneous inflammation directed against microbial and fungal pathogens, but whether neurons serve any role in protective immunity against skin penetrating helminths remains unknown. In this study, we sought to identify the key factors responsible for blocking parasite entry of host skin. Data show that CD4 T cells were essential for restricting parasite entry of the skin during secondary infection, but this resistance was not dependent upon the key TH2 transcription factor Signal Transducer And Activator Of Transcription 6 (STAT6). Interestingly, STAT6 deficient mice generated high levels of TH17 associated cytokines, the latter of which are known to be induced by skin nociceptors. To determine whether skin neurons could prime host protective immunity, we used an optogenetic approach that allowed pre-activation of neurons at the site of skin inoculation that expressed transient receptor potential cation channel subfamily V member 1 (TRPV1). Strikingly, preemptive activation of TRPV1 neurons led to a significant inhibition of parasite entry. Ongoing studies are designed to understand whether depletion of TRPV1 skin neurons impairs immunity and whether skin protection relies upon TH17 dependent immunity. Supported by grants from NIH (R01 AI095289 and R01 GM083204) and NSF GFRP (Fellow ID:2020297782)

Imaging the influence of peripheral TRPV1-signaling on cerebral nociceptive processing applying fMRI-based graph theory in a resiniferatoxin rat model.

Resiniferatoxin (RTX), an extract from the spurge plant Euphorbia resinifera, is a potent agonist of the transient receptor potential cation channel subfamily V member 1 (TRPV1), mainly expressed on peripheral nociceptors—a prerequisite for nociceptive heat perception. Systemic overdosing of RTX can be used to desensitize specifically TRPV1-expressing neurons, and was therefore utilized here to selectively characterize the influence of TRPV1-signaling on central nervous system (CNS) temperature processing. Resting state and CNS temperature processing of male rats were assessed via functional magnetic resonance imaging before and after RTX injection. General linear model-based and graph-theoretical network analyses disentangled the underlying distinct CNS circuitries. At baseline, rats displayed an increase of nociception-related response amplitude and activated brain volume that correlated highly with increasing stimulation temperatures. In contrast, RTX-treated rats showed a clear disruption of thermal nociception, reflected in a missing increase of CNS responses to temperatures above 48°C. Graph-theoretical analyses revealed two distinct brain subnetworks affected by RTX: one subcortical (brainstem, lateral and medial thalamus, hippocampus, basal ganglia and amygdala), and one cortical (primary sensory, motor and association cortices). Resting state analysis revealed first, that peripheral desensitization of TRPV1-expressing neurons did not disrupt the basic resting-state-network of the brain. Second, only at baseline, but not after RTX, noxious stimulation modulated the RS-network in regions associated with memory formation (e.g. hippocampus). Altogether, the combination of whole-brain functional magnetic resonance imaging and RTX-mediated desensitization of TRPV1-signaling provided further detailed insight into cerebral processing of noxious temperatures.

Klotho Ameliorates Podocyte Injury through Targeting TRPC6 Channel in Diabetic Nephropathy.

Podocyte damage is vital for the etiopathogenesis of diabetic nephropathy (DN). Klotho (KL), a multifunctional protein, has been demonstrated to have renoprotective effects; nevertheless, the mechanism for protective effect has not been completely elucidated. Transient receptor potential cation channel subfamily C, member 6 (TRPC6), a potential target of KL, is implicated in glomerular pathophysiology. Here, we sought to determine whether KL could protect against podocyte injury through inhibiting TRPC6 in DN. We found that high glucose (HG) triggered podocyte injury as manifested by actin cytoskeleton damage along with the downregulation of KL and Synaptopodin and the upregulation of TRPC6. KL overexpression reversed HG-induced podocytes injury, whereas cotreatment with TRPC6 activator flufenamic acid (FFA) significantly abrogated the beneficial effects conferred by KL. Moreover, KL knockdown in podocytes resulted in actin cytoskeleton impairment, decreased Synaptopodin expression, and increased TRPC6 expression. In db/db mice, KL overexpression inhibited TRPC6 expression and attenuated diabetes-induced podocyte injury, which was accompanied by decreased albuminuria and ameliorated glomerulosclerosis. Our data provided novel mechanistic insights for KL against DN and highlighted TRPC6 as a new target for KL in podocytes to prevent DN.

Evaluation of oral cancer-induced chemosensitivity

<h3>Introduction</h3> Oral cancer patients experience severe function related pain that impacts quality of life. Some patients report sensitivity to spicy food. Pain is attributed to neuronal sensitization by the release of chemical mediators from the cancer and cancer microenvironment that activate TRPV1 (transient receptor potential cation channel subfamily V member 1). To better understand the underlying mechanisms of oral cancer pain, this study was designed to evaluate cancer-induced chemosensitivity in oral cancer preclinical models. <h3>Materials and Methods</h3> A two-bottle preference test was used to measure aversion to the TRPV1 agonist, capsaicin, the spicy compound in chili peppers. Naïve wild type mice (C57BL/6) were housed two to five mice per cage. Liquid intake over 5-7 day periods was measured from two drinking bottles one with water and capsaicin (0.25 µM – 1 µM) and the other vehicle (0.1% ethanol). Positions of the bottles were exchanged daily to avoid habituation. <h3>Results</h3> Female C57BL/6 mice drank less water with capsaicin for all tested concentrations of capsaicin, demonstrating aversion. Male C57BL/6 mice demonstrated aversion to capsaicin concentrations greater than 0.25 µM. Aversion increased in successive trials, suggesting conditioning or sensitization. Male mice that did not show aversion to 0.25 µM capsaicin over three successive trials demonstrated aversion to 0.25 µM capsaicin after injection in the tongue with complete Freund's adjuvant (20 µl) to generate inflammatory pain. <h3>Conclusions</h3> Female mice showed greater sensitivity to capsaicin than male mice. Aversion to a non-aversive concentration of capsaicin was demonstrated in male mice with inflammatory pain. The lowest dose of capsaicin is expected identify the change in chemosensitivity and difference between sensitive vs. non sensitive cancers.

Capsaicin-Decorated Semiconducting Polymer Nanoparticles for Light-Controlled Calcium-Overload/Photodynamic Combination Therapy.

Calcium-overload cancer therapy has gained more and more attention owing to its good therapeutic efficacy with low side effect. However, conventional calcium-overload therapy is achieved by introducing an additional calcium element into the tumor site by nanomedicines, which may also lead to the calcium-overload of normal organs, causing an undesirable side effect. To address such issues, capsaicin-decorated semiconducting polymer nanoparticles (CSPN) are designed to modulate the calcium ion channel of cancer cells for calcium-overload cancer therapy without adding an additional calcium element. CSPN is composed of a near-infrared (NIR) absorbing semiconducting polymer (SP) PCPDTBT and a capsaicin-conjugated amphiphilic copolymer, PEG-PHEMA-Cap. Under NIR laser irradiation, PCPDTBT can generate singlet oxygen (1 O2 ), which not only triggers the release of capsaicin, but also induces photodynamic therapy (PDT). The released capsaicin can further activate transient receptor potential cation channel subfamily V member 1 (TRPV1) of U373 cancer cells, leading to an influx of calcium ions into cells. In addition, the intense NIR-II fluorescence signal of CSPN makes it suitable for tumor imaging. Thus, this study develops a tumor specific nanotheranostic system for NIR-II fluorescence imaging-guided calcium-overload/PDT combination therapy.

Hydrophobic Derivatives of Sulfated Hyaluronic Acid as Drug Delivery Systems for Multi-Target Intra-Articular Treatment of Post-Traumatic Osteoarthritis

During osteoarthritis (OA) development, chondrocytes progressively decompensate, upregulating proteolytic enzymes and reducing the key growth factors involved in promoting chondrocyte anabolism. A combined therapeutic approach is needed to address this multifactorial pathology, which affects the whole joint. Based on the literature, three promising targets for OA treatment have been selected: MMP3 (matrix metallopeptidase 3), TRPV4 (transient receptor potential cation channel subfamily V member 4) and mTOR (mammalian target of rapamycin). In this study, a novel water-soluble and biocompatible amphiphilic polymer named “sHA-oleylamide” was synthesized and screened from a series of hyaluronic acid derivatives for its anticatabolic activity. This MMP inhibitor showed no cytotoxicity, and in an in vitro model of inflammatory OA, it reversed the inflammatory outcome at a concentration of 0.011 mg/mL. The ability of sHA-oleylamide to form 20–50 nm micelles in water with a critical micelle concentration of 0.27±0.1 mg/mL, was confirmed by TEM images and measured by Nile red staining. RN-1747 and rapamycin molecules were successfully loaded in sHA-oleylamide, previously prepared at 12 mg/mL in PBS; both formulations were stable, sterile and confirmed in vitro to have mTOR inhibition by rapamycin and TRPV4 activation activity by RN-1747.The controlled release of RN-1747 from the micellar formulation with sHA-oleylamide showed that only approximately 60% of the total loaded RN-1747 was released within 7 days. These micellar formulations can potentially increase the bioavailability and pharmaceutical efficacy of the selected active molecules, combining their anti-catabolic and pro-anabolic activities and making them suitable for i.a. administration as OA treatments.

Paracetamol-Induced Hypothermia in Rodents: A Review on Pharmacodynamics

Paracetamol can induce hypothermia in humans and rodents. The study’s aim is to review the mechanisms of paracetamol-induced hypothermia in rodents or the results issued from in vitro studies on the same species’ tissues (in doses that do not produce hepatic impairment) using the latest developments published in scientific journals over the last 15 years. Available human studies are also analysed. An extensive search in PubMed databases exploring the hypothermic response to paracetamol was conducted. 4669 articles about paracetamol’s effects on body temperature in mice or rats were found. After applying additional filters, 20 articles were selected for review, with 9 of them presented in tabular forms. The analysis of these articles found that the hypothermic effect of paracetamol is due to the inhibition of a cyclooxygenase-1 variant, is potentiated by endothelin receptor antagonists, and can be mediated through GABAA receptors and possibly through transient receptor potential cation channel subfamily A member 1 via N-acetyl-p-benzoquinone imine in the central nervous system. Human studies confirm the in vivo and in vitro experiments in rodents regarding the presence of a hypothermic effect after high, non-toxic doses of paracetamol. Further research is required to understand the mechanisms behind paracetamol’s hypothermic effect in humans.

Deciphering the Role of the rs2651899, rs10166942, and rs11172113 Polymorphisms in Migraine: A Meta-Analysis.

The genetic basis of migraine is rather complex. The rs2651899 in the PR/SET domain 16 (PRDM16) gene, the rs10166942 near the transient receptor potential cation channel subfamily M member 8 (TRPM8) gene, and the rs11172113 in the LDL receptor-related protein 1 (LRP1) gene, have been associated with migraine in a genome-wide association study (GWAS). However, data from subsequent studies examining the role of these variants and their relationship with migraine remain inconclusive. The aim of the present study was to meta-analyze the published data assessing the role of these polymorphisms in migraine, migraine with aura (MA), and migraine without aura (MO). We performed a search in the PubMed, Scopus, Web of Science, and Public Health Genomics and Precision Health Knowledge Base (v7.7) databases. In total, eight, six, and six studies were included in the quantitative analysis, for the rs2651899, rs10166942, and rs11172113, respectively. Cochran’s Q and I2 tests were used to calculate the heterogeneity. The random effects (RE) model was applied when high heterogeneity was observed; otherwise, the fixed effects (FE) model was applied. The odds ratios (ORs) and the respective 95% confidence intervals (CIs) were calculated to estimate the effect of each variant on migraine. Funnel plots were created to graphically assess publication bias. A significant association was revealed for the CC genotype of the rs2651899, with the overall migraine group (RE model OR: 1.32; 95% CI: 1.02–1.73; p-value = 0.04) and the MA subgroup (FE model OR: 1.40; 95% CI: 1.12–1.74; p-value = 0.003). The rs10166942 CT genotype was associated with increased migraine risk (FE model OR: 1.36; 95% CI: 1.18–1.57; p-value < 0.0001) and increased MO risk (FE model OR: 1.41; 95% CI: 1.17–1.69; p-value = 0.0003). No association was detected for the rs11172113. The rs2651899 and the rs10166942 have an effect on migraine. Larger studies are needed to dissect the role of these variants in migraine.

Transient Receptor Potential Cation Channel Subfamily V Member 1 Expression Promotes Chemoresistance in Non-Small-Cell Lung Cancer.

Approximately 85% of lung cancer cases are non-small-cell lung cancer (NSCLC). Chemoresistance is a leading cause of chemotherapy failure in NSCLC treatment. Transient receptor potential cation channel subfamily V, member 1 (TRPV1), a non-selective cation channel, plays multiple roles in tumorigenesis and tumor development, including tumor cell proliferation, death, and metastasis as well as the response to therapy. In this study, we found TRPV1 expression was increased in NSCLC. TRPV1 overexpression induced cisplatin (DDP) and fluorouracil (5-FU) resistance in A549 cells independent of its channel function. TRPV1 expression was upregulated in A549-DDP/5-FU resistant cells, and DDP/5-FU sensitivity was restored by TRPV1 knockdown. TRPV1 overexpression mediated DDP and 5-FU resistance by upregulation of ABCA5 drug transporter gene expression, thereby increasing drug efflux, enhancing homologous recombination (HR) DNA repair pathway to alleviate apoptosis and activating IL-8 signaling to promote cell survival. These findings demonstrate an essential role of TRPV1 in chemoresistance in NSCLC and implicate TRPV1 as a potential chemotherapeutic target.

Cysteinyl leukotrienes and acetylcholine are biliary tuft cell cotransmitters.

The gallbladder stores bile between meals and empties into the duodenum upon demand and is thereby exposed to the intestinal microbiome. This exposure raises the need for antimicrobial factors, among them, mucins produced by cholangiocytes, the dominant epithelial cell type in the gallbladder. The role of the much less frequent biliary tuft cells is still unknown. We here show that propionate, a major metabolite of intestinal bacteria, activates tuft cells via the short-chain free fatty acid receptor 2 and downstream signaling involving the cation channel transient receptor potential cation channel subfamily M member 5. This results in corelease of acetylcholine and cysteinyl leukotrienes from tuft cells and evokes synergistic paracrine effects upon the epithelium and the gallbladder smooth muscle, respectively. Acetylcholine triggers mucin release from cholangiocytes, an epithelial defense mechanism, through the muscarinic acetylcholine receptor M3. Cysteinyl leukotrienes cause gallbladder contraction through their cognate receptor CysLTR1, prompting emptying and closing. Our results establish gallbladder tuft cells as sensors of the microbial metabolite propionate, initiating dichotomous innate defense mechanisms through simultaneous release of acetylcholine and cysteinyl leukotrienes.