Role of transient receptor potential vanilloid 1 in inflammation and autoimmune diseases

Cutaneous Application of Capsaicin Cream Reduces Clinical Signs of Experimental Colitis and Repairs Intestinal Barrier Integrity by Modulating the Gut Microbiota and Tight Junction Proteins

Capsaicin, a pungent compound in chili peppers, is described as having potent anti-inflammatory, antioxidant, and antimicrobial properties. It is also described as a potential modulator of the immune system and intestinal microbiota. Oral or rectal administration of capsaicin has been studied to treat or prevent colitis. However, those vias are often not well accepted due to the burning sensation that capsaicin can cause. Our objective was to evaluate whether the application of capsaicin skin creams (0.075%) would be effective in improving inflammation and epithelial barrier function as well as the composition of the gut microbiota in a model of mild colitis induced by dextran sulfate sodium (1.5%). The results showed that the cutaneous application of capsaicin reversed weight loss and decreased colon shortening and diarrhea, all typical signs of colitis. There was also an improvement in the intestinal epithelial barrier, preserving proteins from tight junctions. We also evaluated the biodistribution of 99mtechnetium-radiolabeled capsaicin (99mTc-CAPS) applied to the back skin of the animals. We found significant concentrations of 99 mTc-Cap in the colon and small intestine after 2 and 4 h of administration. In addition, there was an increased expression of capsaicin receptor TRPV1 in the colon. Moreover, animals with colitis receiving cutaneous capsaicin presented a better short-chain fatty acid profile and increased levels of SIgA, suggesting increased microbiota diversity. In conclusion, our work opens avenues for further studies to better understand capsaicin's potential benefits and mechanisms in addressing colitis through cutaneous application.

Volatile Oil Containing Plants as Phytopharmaceuticals to Treat Psoriasis: A Review

INTRODUCTION

Psoriasis is a chronic skin condition caused by an autoimmune response that accelerates the life cycle of skin cells, resulting in the characteristic symptoms of scaling, inflammation, and itching.

METHODS

Palliative treatment options for psoriasis often prioritize the use of volatile oils. These oils contain monoterpenes, sesquiterpenes, and phenylpropanoids that are intricately linked to the molecular cascades involved in the pathogenesis and symptoms of psoriasis. To evaluate the antipsoriatic efficacy of volatile oils and their components, we conducted a systematic review of scientific studies. Our literature search encompassed various online databases, including PubMed, BIREME, SCIELO, Open Grey, Scopus, and ScienceDirect. The selected studies included experimental in vitro/in vivo assessments as well as clinical studies that examined the potential of volatile oils and their extracts as antipsoriatic agents. We excluded conference proceedings, case reports, editorials, and abstracts. Ultimately, we identified and evaluated a total of 12 studies for inclusion in our analysis.

RESULTS

The data collected, compiled, and analyzed strongly support the interaction between volatile oils and their constituents with the key molecular pathways involved in the pathogenesis of psoriasis and the development of its symptoms. Volatile oils play a significant role in the palliative treatment of psoriasis, while their chemical constituents have the potential to reduce the symptoms and recurrence of this condition.

CONCLUSION

The current review highlights that the constituents found in volatile oils offer distinct chemical frameworks that can be regarded as promising starting points for the exploration and development of innovative antipsoriatic agents.

Isolation of Fatty Acids from the Enzymatic Hydrolysis of Capsaicinoids and Their Use in Enzymatic Acidolysis of Coconut Oil

Herein we report the optimization of enzymatic hydrolysis of a mixture of capsaicinoids, capsaicin and dihydrocapsaicin obtained from chili peppers, and the utilization of the isolated fatty acids for the modification of coconut oil using enzyme catalyzed acidolysis. This work was carried out as the fatty acids that can be isolated from capsaicinoid hydrolysis have been shown to possess interesting biological properties. These biological properties could be better exploited by incorporating the fatty acids into a suitable delivery vehicle. The enzymatic hydrolysis of the mixture of capsaicin and dihydrocapsaicin was carried out using Novozym® 435 in phosphate buffer (pH 7.0) at 50℃. The enzyme catalyst could be reused in multiple cycles of the hydrolysis reaction. The desired 8-methyl-6-trans-nonenoic acid and 8-methylnonanoic acid were isolated from the hydrolysis reaction mixture using a simple extraction procedure with a 47.8% yield. This was carried out by first extracting the reaction mixture at pH 10 with ethyl acetate to remove any dissolved capsaicinoids and vanillyl amine side product. The fatty acids were isolated after adjustment of the pH of the reaction mixture to 5 and second extraction with ethyl acetate. The acidolysis of coconut oil with the obtained fatty acids was performed using Lipozyme® TL IM. The performance of the acidolysis reaction was evaluated using 1H-NMR spectroscopy and verified in selected cases using gas chromatography. The best performing conditions involved carrying out the acidolysis reaction at 60℃ with a 1.2 w/w ratio of the fatty acids to coconut oil and 10% enzyme loading for 72 h. This resulted in the incorporation of 26.61% and 9.86% of 8-methyl-6-trans-nonenoic acid and 8-methylnonanoic acid, respectively, into the modified coconut oil product. This product can act as a potential delivery vehicle for these interesting compounds.

TRP channels: Role in neurodegenerative diseases and therapeutic targets

TRP (Transient receptor potential) channels are integral membrane proteins consisting of a superfamily of cation channels that allow permeability of both monovalent and divalent cations. TRP channels are subdivided into six subfamilies: TRPC, TRPV, TRPM, TRPP, TRPML, and TRPA, and are expressed in almost every cell and tissue. TRPs play an instrumental role in the regulation of various physiological processes. TRP channels are extensively represented in brain tissues and are present in both prokaryotes and eukaryotes, exhibiting responses to several mechanisms, including physical, chemical, and thermal stimuli. TRP channels are involved in the perturbation of Ca²⁺ homeostasis in intracellular calcium stores, both in neuronal and non-neuronal cells, and its discrepancy leads to several neuronal disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and Amyotrophic lateral sclerosis (ALS). TRPs participate in neurite outgrowth, receptor signaling, and excitotoxic cell death in the central nervous system. Understanding the mechanism of TRP channels in neurodegenerative diseases may extend to developing novel therapies. Thus, this review articulates TRP channels' physiological and pathological role in exploring new therapeutic interventions in neurodegenerative diseases.

TRPV1 is involved in abdominal hyperalgesia in a mouse model of lipopolysaccharide-induced peritonitis and influences the immune response via peripheral noradrenergic neurons

AIMS

The transient receptor potential vanilloid subfamily 1 (TRPV1) not only plays a role as a nociceptor but also has some regulatory effects on the immune system. We investigated the effects of TRPV1 on abdominal pain and the immune system in lipopolysaccharide (LPS)-induced peritonitis and the association between TRPV1 and peripheral noradrenergic neurons.

MAIN METHODS

Experiments were performed in 8- to 14-week-old male wild-type (WT) and TRPV1 knockout (KO) mice. The mice were intraperitoneally injected with a non-lethal dose of LPS. Pain assessment and investigation of changes in the immune system were performed. Denervation of sympathetic nerves and the noradrenergic splenic nerve was induced by intraperitoneal administration of 6-hydroxydopamine.

KEY FINDINGS

The levels of serum cytokines were not significantly different in WT mice and TRPV1 KO mice. Abdominal mechanical hyperalgesia was greater in WT mice than in TRPV1 KO mice from 6 h to 3 days. The numbers of macrophages, neutrophils, dendritic cells, and CD4 T cells in the spleens of TRPV1 KO mice were significantly increased compared to those in WT mice 4 days after LPS administration. By noradrenergic denervation, the numbers of those cells in WT mice increased to levels comparable to those in TRPV1 KO mice.

SIGNIFICANCE

In LPS-induced peritonitis, abdominal inflammatory pain was transmitted via TRPV1. In addition, TRPV1 had an anti-inflammatory effect on the spleen in the late phase of peritonitis. This anti-inflammatory effect was thought to be mediated by activation of the sympathetic nervous system and/or noradrenergic splenic nerve induced by TRPV1 activation.

Influence of water-based exercise on energy intake, appetite, and appetite-related hormones in adults: A systematic review and meta-analysis

Single bouts of land-based exercise suppress appetite and do not typically alter energy intake in the short-term, whereas it has been suggested that water-based exercise may evoke orexigenic effects. The primary aim was to systematically review the available literature investigating the influence of water-based exercise on energy intake in adults (PROSPERO ID number CRD42022314349). PubMed, Medline, Sport-Discus, Academic Search Complete, CINAHL and Public Health Database were searched for peer-reviewed articles published in English from 1900 to May 2022. Included studies implemented a water-based exercise intervention versus a control or comparator. Risk of bias was assessed using the revised Cochrane 'Risk of bias tool for randomised trials' (RoB 2.0). We identified eight acute (same day) exercise studies which met the inclusion criteria. Meta-analysis was performed using a fixed effects generic inverse variance method on energy intake (8 studies (water versus control), 5 studies (water versus land) and 2 studies (water at two different temperatures)). Appetite and appetite-related hormones are also examined but high heterogeneity did not allow a meta-analysis of these outcome measures. We identified one chronic exercise training study which met the inclusion criteria with findings discussed narratively. Meta-analysis revealed that a single bout of exercise in water increased ad-libitum energy intake compared to a non-exercise control (mean difference [95% CI]: 330 [118, 542] kJ, P = 0.002). No difference in ad libitum energy intake was identified between water and land-based exercise (78 [-176, 334] kJ, P = 0.55). Exercising in cold water (18-20 °C) increased energy intake to a greater extent than neutral water (27-33 °C) temperature (719 [222, 1215] kJ; P < 0.005). The one eligible 12-week study did not assess whether water-based exercise influenced energy intake but did find that cycling and swimming did not alter fasting plasma concentrations of total ghrelin, insulin, leptin or total PYY but contributed to body mass loss 87.3 (5.2) to 85.9 (5.0) kg and 88.9 (4.9) to 86.4 (4.5) kg (P < 0.05) respectively. To conclude, if body mass management is a person's primary focus, they should be mindful of the tendency to eat more in the hours after a water-based exercise session, particularly when the water temperature is cold (18-20 °C).

Phytochemicals and Inflammation: Is Bitter Better?

The taste of a herb influences its use in traditional medicine. A molecular basis for the taste-based patterns ruling the distribution of herbal (ethno) pharmacological activities may not be excluded. This study investigated the potential correlations between the anti-inflammatory activity (AIA) and the phytocompound taste and/or its chemical class. The study relies on information gathered by an extensive literature (articles, books, databases) search and made public as PlantMolecularTasteDB. Out of a total of 1527 phytotastants with reliably documented taste and structure available in PlantMolecularTasteDB, 592 (for each of which at least 40 hits were found on PubMed searches) were included in the statistical analysis. A list of 1836 putative molecular targets of these phytotastants was afterwards generated with SwissTargetPrediction tool. These targets were systematically evaluated for their potential role in inflammation using an international databases search. The correlations between phytochemical taste and AIA, between chemical class and AIA, and between the taste and the number of inflammation related targets were statistically analyzed. Phytochemical taste may be a better predictor of AIA than the chemical class. Bitter phytocompounds have a higher probability of exerting AIA when compared with otherwise phytotastants. Moreover, bitter phytotastants act upon more inflammation related targets than non-bitter tasting compounds.

Nociceptors: Their Role in Body’s Defenses, Tissue Specific Variations and Anatomical Update

The human body is constantly under the influence of numerous pathological factors: both external and internal. These factors can be potentially harmful and are perceived as such with a specialized nervous system subunit: the nociceptive system. The functional unit of the nociceptive system is the nociceptor. Recent studies have shown that nociceptors play a crucial role in maintaining of defensive homeostasis (responsive, immune, behavioral). Nociceptors respond to potentially harmful stimuli within viscera, bones, muscles, skin and specialized sensory organs. They function as complex predictors of harm through formation of pain stimulus. Their function and structures vary within different tissues. This variability reflects the anatomical and pathological peculiarities of varying tissues. Nociceptors play a significant role in adaptive, protective and behavioral reactions. Their functional capabilities and vast spread throughout the body make them the main units of the body’s defense system, allowing us to interact with the inner and outer environments.

Anti-Inflammatory Effect of Beta-Caryophyllene Mediated by the Involvement of TRPV1, BDNF and trkB in the Rat Cerebral Cortex after Hypoperfusion/Reperfusion

We have previously shown that bilateral common carotid artery occlusion followed by reperfusion (BCCAO/R) is a model to study early hypoperfusion/reperfusion-induced changes in biomarkers of the tissue physiological response to oxidative stress and inflammation. Thus in this study, we investigate with immunochemical assays if a single dose of beta-caryophyllene (BCP), administered before the BCCAO/R, can modulate the TRPV1, BDNF, and trkB receptor in the brain cortex; the glial markers GFAP and Iba1 were also examined. Frontal and temporal-occipital cortical regions were analyzed in two groups of male rats, sham-operated and submitted to BCCAO/R. Six hours before surgery, one group was gavage fed a dose of BCP (40 mg/per rat in 300 μL of sunflower oil), the other was pre-treated with the vehicle alone. Western blot analysis showed that, in the frontal cortex of vehicle-treated rats, the BCCAO/R caused a TRPV1 decrease, an increment of trkB and GFAP, no change in BDNF and Iba1. The BCP treatment caused a decrease of BDNF and an increase of trkB levels in both sham and BCCAO/R conditions while inducing opposite changes in the case of TRPV1, whose levels became higher in BCCAO/R and lower in sham conditions. Present results highlight the role of BCP in modulating early events of the cerebral inflammation triggered by the BCCAO/R through the regulation of TRPV1 and the BDNF-trkB system.

The industrial solvent 1,4-dioxane causes hyperalgesia by targeting capsaicin receptor TRPV1

BACKGROUND

The synthetic chemical 1,4-dioxane is used as industrial solvent, food, and care product additive. 1,4-Dioxane has been noted to influence the nervous system in long-term animal experiments and in humans, but the molecular mechanisms underlying its effects on animals were not previously known.

RESULTS

Here, we report that 1,4-dioxane potentiates the capsaicin-sensitive transient receptor potential (TRP) channel TRPV1, thereby causing hyperalgesia in mouse model. This effect was abolished by CRISPR/Cas9-mediated genetic deletion of TRPV1 in sensory neurons, but enhanced under inflammatory conditions. 1,4-Dioxane lowered the temperature threshold for TRPV1 thermal activation and potentiated the channel sensitivity to agonistic stimuli. 1,3-dioxane and tetrahydrofuran which are structurally related to 1,4-dioxane also potentiated TRPV1 activation. The residue M572 in the S4-S5 linker region of TRPV1 was found to be crucial for direct activation of the channel by 1,4-dioxane and its analogs. A single residue mutation M572V abrogated the 1,4-dioxane-evoked currents while largely preserving the capsaicin responses. Our results further demonstrate that this residue exerts a gating effect through hydrophobic interactions and support the existence of discrete domains for multimodal gating of TRPV1 channel.

CONCLUSIONS

Our results suggest TRPV1 is a co-receptor for 1,4-dioxane and that this accounts for its ability to dysregulate body nociceptive sensation.

Endocannabinoid System as a Promising Therapeutic Target in Inflammatory Bowel Disease - A Systematic Review

Inflammatory bowel disease (IBD) is a general term used to describe a group of chronic inflammatory conditions of the gastrointestinal tract of unknown etiology, including two primary forms: Crohn's disease (CD) and ulcerative colitis (UC). The endocannabinoid system (ECS) plays an important role in modulating many physiological processes including intestinal homeostasis, modulation of gastrointestinal motility, visceral sensation, or immunomodulation of inflammation in IBD. It consists of cannabinoid receptors (CB1 and CB2), transporters for cellular uptake of endocannabinoid ligands, endogenous bioactive lipids (Anandamide and 2-arachidonoylglycerol), and the enzymes responsible for their synthesis and degradation (fatty acid amide hydrolase and monoacylglycerol lipase), the manipulation of which through agonists and antagonists of the system, shows a potential therapeutic role for ECS in inflammatory bowel disease. This review summarizes the role of ECS components on intestinal inflammation, suggesting the advantages of cannabinoid-based therapies in inflammatory bowel disease.

Sensory Neurons, Neuroimmunity, and Pain Modulation by Sex Hormones

The inclusion of women in preclinical pain studies has become more commonplace in the last decade as the National Institutes of Health (NIH) released its "Sex as a Biological Variable" mandate. Presumably, basic researchers have not had a comprehensive understanding about neuroimmune interactions in half of the population and how hormones play a role in this. To date, we have learned that sex hormones contribute to sexual differentiation of the nervous system and sex differences in behavior throughout the lifespan; however, the cycling of sex hormones does not always explain these differences. Here, we highlight recent advances in our understanding of sex differences and how hormones and immune interactions influence sensory neuron activity to contribute to physiology and pain. Neuroimmune mechanisms may be mediated by different cell types in each sex, as the actions of immune cells are sexually dimorphic. Unfortunately, the majority of studies assessing neuronal contributions to immune function have been limited to males, so it is unclear if the mechanisms are similar in females. Finally, pathways that control cellular metabolism, like nuclear receptors, have been shown to play a regulatory role both in pain and inflammation. Overall, communication between the neuroimmune and endocrine systems modulate pain signaling in a sex-dependent manner, but more research is needed to reveal nuances of these mechanisms.

TRPV1 Hyperfunction Contributes to Renal Inflammation in Oxalate Nephropathy

Inflammation worsens oxalate nephropathy by exacerbating tubular damage. The transient receptor potential vanilloid 1 (TRPV1) channel is present in kidney and has a polymodal sensing ability. Here, we tested whether TRPV1 plays a role in hyperoxaluria-induced renal inflammation. In TRPV1-expressed proximal tubular cells LLC-PK₁, oxalate could induce cell damage in a time- and dose-dependent manner; this was associated with increased arachidonate 12-lipoxygenase (ALOX12) expression and synthesis of endovanilloid 12(S)-hydroxyeicosatetraenoic acid for TRPV1 activation. Inhibition of ALOX12 or TRPV1 attenuated oxalate-mediated cell damage. We further showed that increases in intracellular Ca²⁺ and protein kinase C α activation are downstream of TRPV1 for NADPH oxidase 4 upregulation and reactive oxygen species formation. These trigger tubular cell inflammation via increased NLR family pyrin domain-containing 3 expression, caspase-1 activation, and interleukin (IL)-1β release, and were alleviated by TRPV1 inhibition. Male hyperoxaluric rats demonstrated urinary supersaturation, tubular damage, and oxidative stress in a time-dependent manner. Chronic TRPV1 inhibition did not affect hyperoxaluria and urinary supersaturation, but markedly reduced tubular damage and calcium oxalate crystal deposition by lowering oxidative stress and inflammatory signaling. Taking all these results together, we conclude that TRPV1 hyperfunction contributes to oxalate-induced renal inflammation. Blunting TRPV1 function attenuates hyperoxaluric nephropathy.

Neuronal interleukin-1 receptors mediate pain in chronic inflammatory diseases

Chronic pain is a major comorbidity of chronic inflammatory diseases. Here, we report that the cytokine IL-1β, which is abundantly produced during multiple sclerosis (MS), arthritis (RA), and osteoarthritis (OA) both in humans and in animal models, drives pain associated with these diseases. We found that the type 1 IL-1 receptor (IL-1R1) is highly expressed in the mouse and human by a subpopulation of TRPV1⁺ dorsal root ganglion neurons specialized in detecting painful stimuli, termed nociceptors. Strikingly, deletion of the Il1r1 gene specifically in TRPV1⁺ nociceptors prevented the development of mechanical allodynia without affecting clinical signs and disease progression in mice with experimental autoimmune encephalomyelitis and K/BxN serum transfer–induced RA. Conditional restoration of IL-1R1 expression in nociceptors of IL-1R1–knockout mice induced pain behavior but did not affect joint damage in monosodium iodoacetate–induced OA. Collectively, these data reveal that neuronal IL-1R1 signaling mediates pain, uncovering the potential benefit of anti–IL-1 therapies for pain management in patients with chronic inflammatory diseases.

Emerging potential of cannabidiol in reversing proteinopathies

The aberrant accumulation of disease-specific protein aggregates accompanying cognitive decline is a pathological hallmark of age-associated neurological disorders, also termed as proteinopathies, including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and multiple sclerosis. Along with oxidative stress and neuroinflammation, disruption in protein homeostasis (proteostasis), a network that constitutes protein surveillance system, plays a pivotal role in the pathobiology of these dementia disorders. Cannabidiol (CBD), a non-psychotropic phytocannabinoid of Cannabis sativa, is known for its pleiotropic neuropharmacological effects on the central nervous system, including the ability to abate oxidative stress, neuroinflammation, and protein misfolding. Over the past years, compelling evidence has documented disease-modifying role of CBD in various preclinical and clinical models of neurological disorders, suggesting the potential therapeutic implications of CBD in these disorders. Because of its putative role in the proteostasis network in particular, CBD could be a potent modulator for reversing not only age-associated neurodegeneration but also other protein misfolding disorders. However, the current understanding is insufficient to underpin this proposition. In this review, we discuss the potentiality of CBD as a pharmacological modulator of the proteostasis network, highlighting its neuroprotective and aggregates clearing roles in the neurodegenerative disorders. We anticipate that the current effort will advance our knowledge on the implication of CBD in proteostasis network, opening up a new therapeutic window for aging proteinopathies.

Cannabinoids in Dermatology: Hope or Hype?

Cannabinoids (CBDs) represent a diverse class of chemicals that may be beneficial in the treatment of various skin diseases due to antipruritic, anti-inflammatory, and antinociceptive properties. Although the legal history of these compounds has previously restricted their use and study, it seems likely that CBDs will gain popularity as they become increasingly available. We examined the mechanisms in which CBDs may have potential in the field of dermatology and reviewed the existing literature. We suggest that dermatologists review the existing evidence for CBD use and be ready to discuss it with their patients. The current literature indicates that CBDs may be beneficial in skin disease, particularly in the treatment of acne, chronic pruritus, and atopic dermatitis. Although there is preliminary evidence to suggest that CBDs are beneficial in these conditions, existing studies tend to be small and lacking rigorous design. There is a clear need for high-quality randomized controlled trials to fully evaluate the efficacy and safety of these compounds before their use can be promoted in the treatment of dermatological diseases.

Differential Profile of Plasma Circular RNAs in Type 1 Diabetes Mellitus

BACKGROUND

No currently available biomarkers or treatment regimens fully meet therapeutic needs of type 1 diabetes mellitus (T1DM). Circular RNA (circRNA) is a recently identified class of stable noncoding RNA that have been documented as potential biomarkers for various diseases. Our objective was to identify and analyze plasma circRNAs altered in T1DM.

METHODS

We used microarray to screen differentially expressed plasma circRNAs in patients with new onset T1DM (n=3) and age-/gender-matched healthy controls (n=3). Then, we selected six candidates with highest fold-change and validated them by quantitative real-time polymerase chain reaction in independent human cohort samples (n=12). Bioinformatic tools were adopted to predict putative microRNAs (miRNAs) sponged by these validated circRNAs and their downstream messenger RNAs (mRNAs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to gain further insights into T1DM pathogenesis.

RESULTS

We identified 68 differentially expressed circRNAs, with 61 and seven being up- and downregulated respectively. Four of the six selected candidates were successfully validated. Curations of their predicted interacting miRNAs revealed critical roles in inflammation and pathogenesis of autoimmune disorders. Functional relations were visualized by a circRNA-miRNA-mRNA network. GO and KEGG analyses identified multiple inflammation-related processes that could be potentially associated with T1DM pathogenesis, including cytokine-cytokine receptor interaction, inflammatory mediator regulation of transient receptor potential channels and leukocyte activation involved in immune response.

CONCLUSION

Our study report, for the first time, a profile of differentially expressed plasma circRNAs in new onset T1DM. Further in silico annotations and bioinformatics analyses supported future application of circRNAs as novel biomarkers of T1DM.

Di-(2-ethylhexyl) phthalate limits the pleiotropic effects of statins in chronic kidney disease patients undergoing dialysis and endothelial cells

The level of di-(2-ethylhexyl) phthalate (DEHP) is elevated in chronic kidney disease patients undergoing dialysis. However, statins are unable to reduce the cardiovascular events in chronic dialysis patients. In this study, we investigated the effects of DEHP on statin-conferred pleiotropic effects and the underlying molecular mechanism in peritoneal dialysis (PD) patients and endothelial cells (ECs). In PD patients with serum DEHP level ≥0.0687 μg/mL, statin treatment was not associated with lower risk of cardiovascular disease. In ECs, exposure to DEHP abrogated the simvastatin-induced NO bioavailability and EC-related functions. Additionally, DEHP abolished the anti-inflammatory effect of simvastatin on the tumor necrosis factor α-induced upregulation of adhesion molecules and monocyte adhesion to ECs. Mechanistically, DEHP blunted the activation of transient receptor potential vanilloid type 1 (TRPV1), which is required for NO production by simvastatin in ECs. Notably, DEHP increased the activity and expression of protein phosphatase 2B (PP2B), a negative regulator of TRPV1 activity. The effect of DEHP on PP2B activation was mediated by the activation of the NADPH oxidase/reactive oxygen species (NOX-ROS) pathway. Inhibition of PP2B activity by pharmacological antagonists prevented the inhibitory effects of DEHP on simvastatin-induced Ca²⁺ influx, NO bioavailability, and EC migration, proliferation, tube formation, and anti-inflammatory action. Collectively, DEHP activates the NOX-ROS-PP2B pathway, which in turns inhibits TRPV1/Ca²⁺-dependent signaling and abrogates the statin-conferred pleiotropic protection in ECs.

Inhibition of transient receptor potential vanilloid 1 (TRPV1) channel regulates chikungunya virus infection in macrophages

Chikungunya virus (CHIKV), a virus that induces pathogenic inflammatory host immune responses, is re-emerging worldwide, and there are currently no established antiviral control measures. Transient receptor potential vanilloid 1 (TRPV1), a non-selective Ca²⁺-permeable ion channel, has been found to regulate various host inflammatory responses including several viral infections. Immune responses to CHIKV infection in host macrophages have been reported recently. However, the possible involvement of TRPV1 during CHIKV infection in host macrophages has not been studied. Here, we investigated the possible role of TRPV1 in CHIKV infection of the macrophage cell line RAW 264.7. It was found that CHIKV infection upregulates TRPV1 expression in macrophages. To confirm this observation, the TRPV1-specific modulators 5'-iodoresiniferatoxin (5'-IRTX, a TRPV1 antagonist) and resiniferatoxin (RTX, a TRPV1 agonist) were used. Our results indicated that TRPV1 inhibition leads to a reduction in CHIKV infection, whereas TRPV1 activation significantly enhances CHIKV infection. Using a plaque assay and a time-of-addition assay, it was observed that functional modulation of TRPV1 affects the early stages of the viral lifecycle in RAW 264.7 cells. Moreover, CHIKV infection was found to induce of pNF-κB (p65) expression and nuclear localization. However, both activation and inhibition of TRPV1 were found to enhance the expression and nuclear localization of pNF-κB (p65) and production of pro-inflammatory TNF and IL-6 during CHIKV infection. In addition, it was demonstrated by Ca²⁺ imaging that TRPV1 regulates Ca²⁺ influx during CHIKV infection. Hence, the current findings highlight a potentially important regulatory role of TRPV1 during CHIKV infection in macrophages. This study might also have broad implications in the context of other viral infections as well.

Strategies to reduce the risk of platinum containing antineoplastic drug-induced ototoxicity

INTRODUCTION

Cisplatin is a highly effective chemotherapeutic agent against a variety of solid tumors in adults and in children. Unfortunately, a large percentage of patients suffer permanent sensorineural hearing loss. Up to 60% of children and at least 50% of adults suffer this complication that seriously compromises their quality of life. Hearing loss is due to damage to the sensory cells in the inner ear. The mechanisms of cochlear damage are still being investigated. However, it appears that inner ear damage is triggered by reactive oxygen species (ROS) formation and inflammation 34.

AREAS COVERED

We discuss a number of potential therapeutic targets that can be addressed to provide hearing protection. These strategies include enhancing the endogenous antioxidant pathways, heat shock proteins, G protein coupled receptors and counteracting ROS and reactive nitrogen species, and blocking pathways that produce inflammation, including TRPV1 and STAT1 36.

EXPERT OPINION

Numerous potential protective agents show promise in animal models by systemic or local administration. However, clinical trials have not shown much efficacy to date with the exception of sodium thiosulfate. There is an urgent need to discover safe and effective protective agents that do not interfere with the efficacy of cisplatin against tumors yet preserve hearing 151.

TRP Channels Role in Pain Associated With Neurodegenerative Diseases

Transient receptor potential (TRP) are cation channels expressed in both non-excitable and excitable cells from diverse tissues, including heart, lung, and brain. The TRP channel family includes 28 isoforms activated by physical and chemical stimuli, such as temperature, pH, osmotic pressure, and noxious stimuli. Recently, it has been shown that TRP channels are also directly or indirectly activated by reactive oxygen species. Oxidative stress plays an essential role in neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases, and TRP channels are involved in the progression of those diseases by mechanisms involving changes in the crosstalk between Ca2+ regulation, oxidative stress, and production of inflammatory mediators. TRP channels involved in nociception include members of the TRPV, TRPM, TRPA, and TRPC subfamilies that transduce physical and chemical noxious stimuli. It has also been reported that pain is a complex issue in patients with Alzheimer's and Parkinson's diseases, and adequate management of pain in those conditions is still in discussion. TRPV1 has a role in neuroinflammation, a critical mechanism involved in neurodegeneration. Therefore, some studies have considered TRPV1 as a target for both pain treatment and neurodegenerative disorders. Thus, this review aimed to describe the TRP-dependent mechanism that can mediate pain sensation in neurodegenerative diseases and the therapeutic approach available to palliate pain and neurodegenerative symptoms throughout the regulation of these channels.

Immunomodulatory and anti-oxidative effect of the direct TRPV1 receptor agonist capsaicin on Schwann cells

Background

Only few studies describe the impact of nutritive factors on chronic inflammatory demyelinating polyneuropathy (CIDP), an inflammatory disease of the peripheral nervous system. The active component of chili pepper, capsaicin, is the direct agonist of the transient receptor potential channel vanilloid subfamily member 1. Its anti-inflammatory effect in the animal model experimental autoimmune neuritis (EAN) has been previously demonstrated.

Methods

In the present study, we describe the anti-inflammatory and anti-oxidative influence of capsaicin on Schwann cells (SCs) in an in vitro setting. Hereby, we analyze the effect of capsaicin on Schwann cells’ gene expression pattern, major histocompatibility complex class II (MHC-II) presentation, and H₂O₂-induced oxidative stress. Furthermore, the effect of capsaicin on myelination was examined in a SC-dorsal root ganglia (DRG) coculture by myelin basic protein staining. Finally, in order to investigate the isolated effect of capsaicin on SCs in EAN pathology, we transplant naïve and capsaicin pre-treated SCs intrathecally in EAN immunized rats and analyzed clinical presentation, electrophysiological parameters, and cytokine expression in the sciatic nerve.

Results

In SC monoculture, incubation with capsaicin significantly reduces interferon gamma-induced MHC-II production as well as toll-like receptor 4 and intercellular adhesion molecule 1 mRNA expression. Calcitonin gene-related peptide mRNA production is significantly upregulated after capsaicin treatment. Capsaicin reduces H₂O₂-induced oxidative stress in SC in a preventive, but not therapeutic setting. In a SC-DRG coculture, capsaicin does not affect myelination rate. After intrathecal transplantation of naïve and capsaicin pre-treated SCs in EAN-immunized rats, naïve, but not capsaicin pre-treated intrathecal SCs, ameliorated EAN pathology in rats.

Conclusions

In conclusion, we were able to demonstrate a direct immunomodulatory and anti-oxidative effect of capsaicin in a SC culture by reduced antigen presentation and expression of an anti-inflammatory profile. Furthermore, capsaicin increases the resistance of SCs against oxidative stress. A primary effect of capsaicin on myelination was not proven. These results are in concordance with previous data showing an anti-inflammatory effect of capsaicin, which might be highly relevant for CIDP patients.

A Guide to Targeting the Endocannabinoid System in Drug Design

The endocannabinoid system (ECS) is one of the most crucial systems in the human organism, exhibiting multi-purpose regulatory character. It is engaged in a vast array of physiological processes, including nociception, mood regulation, cognitive functions, neurogenesis and neuroprotection, appetite, lipid metabolism, as well as cell growth and proliferation. Thus, ECS proteins, including cannabinoid receptors and their endogenous ligands’ synthesizing and degrading enzymes, are promising therapeutic targets. Their modulation has been employed in or extensively studied as a treatment of multiple diseases. However, due to a complex nature of ECS and its crosstalk with other biological systems, the development of novel drugs turned out to be a challenging task. In this review, we summarize potential therapeutic applications for ECS-targeting drugs, especially focusing on promising synthetic compounds and preclinical studies. We put emphasis on modulation of specific proteins of ECS in different pathophysiological areas. In addition, we stress possible difficulties and risks and highlight proposed solutions. By presenting this review, we point out information pivotal in the spotlight of ECS-targeting drug design, as well as provide an overview of the current state of knowledge on ECS-related pharmacodynamics and show possible directions for needed research.

Role of neuroimmune circuits and pruritus in psoriasis

Psoriasis is a chronic inflammatory skin disease presenting with an array of clinical phenotypes, often associated with pruritus. Environmental and psychological stressors can exacerbate psoriasis symptoms and provoke flares. Recent studies suggest a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis in some patients with psoriasis that can result in immune dysregulation. The immune system, in turn, can communicate with the nervous system to induce, maintain or aggravate psoriasis. In the skin, peripheral sensory as well as autonomic nerves control release of inflammatory mediators from dendritic cells, mast cells, T cells or keratinocytes, thereby modulating inflammatory responses and, in case of sensory nerves, pruritus. In response to the environment or stress, cytokines, chemokines, proteases, and neuropeptides fluctuate in psoriasis and influence immune responses as well as nerve activity. Furthermore, immune cells communicate with sensory nerves which control release of cytokines, such as IL-23, that are ultimately involved in psoriasis pathogenesis. Nerves also communicate with keratinocytes to induce epidermal proliferation. Notably, in contrast to recent years the debilitating problem of pruritus in psoriasis has been increasingly appreciated. Thus, investigating neuroimmune communication in psoriasis will not only expand our knowledge about the impact of sensory nerves in inflammation and pruritus and give new insights into the impact of environmental factors activating neuroimmune circuits or of stress in psoriasis, but may also lead to novel therapies. This review summarizes the relevant literature on the role of neuroimmune circuits, stress and how the central HPA axis and its peripheral equivalent in the skin, impact psoriasis.

TRPV1 in experimental autoimmune prostatitis

BACKGROUND

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a disorder that is characterized by persistent pelvic pain in men of any age. Although several studies suggest that the transient receptor potential vanilloid 1 (TRPV1) channel is involved in various pathways of chronic pain, the TRPV1 channel has not been implicated in chronic pelvic pain associated with CP/CPPS.

METHODS

Male C57BL/6J (B6) and TRPV1 knockout (TRPV1 KO) mice (5-7 weeks old) were used to study the development of pelvic allodynia in a murine model of CP/CPPS called experimental autoimmune prostatitis (EAP). The prostate lobes, dorsal root ganglia (DRG), and spinal cord were excised at day 20. The prostate lobes were assessed for inflammation, TRPV1 expression, and mast cell activity. DRG and spinal cord, between the L6-S4 regions, were analyzed to determine the levels of phosphorylated ERK1/2 (p-ERK 1/2). To examine the therapeutic potential of TRPV1, B6 mice with EAP received intraurethral infusion of a TRPV1 antagonist at day 20 (repeated every 2 days) and pelvic pain was evaluated at days 20, 25, 30, and 35.

RESULTS

Our data showed that B6 mice with EAP developed pelvic tactile allodynia at days 7, 14, and 20. In contrast, TRPV1 KO mice with EAP do not develop pelvic tactile allodynia at any time point. Although we observed no change in the levels of TRPV1 protein expression in the prostate from B6 mice with EAP, there was evidence of significant inflammation and elevated mast cell activation. Interestingly, the prostate from TRPV1 KO mice with EAP showed a lack of mast cell activation despite evidence of prostate inflammation. Next, we observed a significant increase of p-ERK1/2 in the DRG and spinal cord from B6 mice with EAP; however, p-ERK1/2 expression was unaltered in TRPV1 KO mice with EAP. Finally, we confirmed that intraurethral administration of a TRPV1 antagonist peptide reduced pelvic tactile allodynia in B6 mice with EAP after day 20.

CONCLUSIONS

We demonstrated that in a murine model of CP/CPPS, the TRPV1 channel is key to persistent pelvic tactile allodynia and blocking TRPV1 in the prostate may be a promising strategy to quell chronic pelvic pain.

Inflammation, Cancer and Immunity-Implication of TRPV1 Channel

Process of inflammation and complex interactions between immune and cancer cells within tumor microenvironment are known to drive and shape the outcome of the neoplastic disease. Recent studies increasingly show that ion channels can be used as potential targets to modulate immune response and to treat inflammatory disorders and cancer. The action of both innate and adaptive immune cells is tightly regulated by ionic signals provided by a network of distinct ion channels. TRPV1 channel, known as a capsaicin receptor, was recently documented to be expressed on the cells of the immune system but also aberrantly expressed in the several tumor types. It is activated by heat, protons, proinflammatory cytokines, and associated with pain and inflammation. TRPV1 channel is not only involved in calcium signaling fundamental for many cellular processes but also takes part in cell-environment crosstalk influencing cell behavior. Furthermore, in several studies, activation of TRPV1 by capsaicin was associated with anti-cancer effects. Therefore, TRPV1 provides a potential link between the process of inflammation, cancer and immunity, and offers new treatment possibilities. Nevertheless, in many cases, results regarding TRPV1 are contradictory and need further refinement. In this review we present the summary of the data related to the role of TRPV1 channel in the process of inflammation, cancer and immunity, limitations of the studies, and directions for future research.

Multi-target-directed-ligands acting as enzyme inhibitors and receptor ligands

In this review, we present the latest advances in the field of multi-target-directed ligand (MTDL) design for the treatment of various complex pathologies of multifactorial origin. In particular, latest findings in the field of MTDL design targeting both an enzyme and a receptor are presented for different diseases such as Alzheimer's disease (AD), depression, addiction, glaucoma, non-alcoholic steatohepatitis and pain and inflammation. The ethology of the diseases is briefly described, with special emphasis on how the MTDL can evolve into novel therapies that replace the classic pharmacological dogma "one target one disease". Considering the current needs for therapy adherence improvement, it is exposed as from the medicinal chemistry, different molecular scaffolds are studied. With the use of structure activity relationship studies and molecular optimization, new hybrid molecules are generated with improved biological properties acting at two biologically very distinct targets.

A Single Injection of N-Oleoyldopamine, an Endogenous Agonist for Transient Receptor Potential Vanilloid-1, Induced Brain Hypothermia, but No Neuroprotective Effects in Experimentally Induced Cerebral Ischemia in Rats

Targeted temperature management, or therapeutic hypothermia, is a potent neuroprotective approach after ischemic brain injury. Hypothermia should be induced as soon as possible after the onset of acute stroke to assure better outcomes. Accordingly, drugs with a fast-acting hypothermic effect sustainable through the period of emergency transportation to hospital would have clinical advantages. Activation of the transient receptor potential vanilloid-1 (TRPV1) can induce hypothermia. Our immunohistochemical investigations confirmed that TRPV1 was distributed to perivascular and periventricular regions of the rat brain, where TRPV1 can be easily detected by TRPV1 agonists. An endogenous TRPV1 selective agonist, N-oleoyldopamine (OLDA), and a synthetic antagonist, AMG 9810, were injected intraperitoneally into healthy adult male Wister rats, and brain and core temperatures and gross motor activities were monitored. Comparison with baseline temperatures showed that TRPV1 injection immediately induced mild hypothermia (p < 0.05 in brain and p < 0.01 in body), and AMG 9810 induced immediate mild hyperthermia (not significant). However, the OLDA-induced hypothermia did not decrease lesion volume after middle carotid artery occlusion in rats. Relative to vehicle, OLDA yielded poorer outcomes and AMG 9810 yielded better outcomes in neurological scores and lesion size. Our study showed that, as an agonist of TRPV1, OLDA has suitable hypothermia-inducing properties, but did not decrease lesion volume. Therefore, the search for novel TRPV1 agonists and/or antagonists providing hypothermia and neuroprotection should continue. Further investigations should also target OLDA-induced transient hypothermia combined with long-term hypothermia maintenance with surface cooling, which mimics the anticipated clinical use of this class of drug.

Redox TRPs in diabetes and diabetic complications: Mechanisms and pharmacological modulation

Transient receptor potential (TRP) channels have shown to be involved in a wide variety of physiological functions and pathophysiological conditions. Modulation of TRP channels reported to play a major role in number of disorders starting from central nervous system related disorders to cardiovascular, inflammatory, cancer, gastrointestinal and metabolic diseases. Recently, a subset of TRP ion channels called redox TRPs gained importance on account of their ability to sense the cellular redox environment and respond accordingly to such redox stimuli. Diabetes, the silent epidemic of the world is increasing at an alarming rate in spite of novel therapeutic interventions. Moreover, diabetes and its associated complications are reported to arise due to a change in oxidative status of cell induced by hyperglycemia. Such a change in cellular oxidative status can modulate the activities of various redox TRP channels (TRPA1, TRPC5, TRPMs and TRPV1). Targeting redox TRPs have potential in diabetes and diabetic complications like neuropathy, cardiomyopathy, retinopathy, cystopathy, and encephalopathy. Thus in this review, we have discussed the activities of different redox sensing TRPs in diabetes and diabetic complications and how they can be modulated pharmacologically, so as to consider them a potential novel therapeutic target in treating diabetes and its comorbidity.

Emerging class of omega-3 fatty acid endocannabinoids & their derivatives

Cannabinoid receptor activation is involved in homeostatic regulation of the body. These receptors are activated by cannabinoids, that include the active constituents of Cannabis sativa, as well as endocannabinoids (eCBs). The eCBs are endogenously synthesized from the omega-6 and omega-3 polyunsaturated fatty acids (PUFAs). The consumption of omega-3 fatty acids shifts the balance towards a higher proportion of omega-3 eCBs, whose physiological functions warrants further investigation. Herein, we review the discovery of omega-3 fatty acid derived eCBs that are generated from long chain omega-3 PUFAs - docosahexaenoyl ethanolamide (DHA-EA or synaptamide), docosahexanoyl-glycerol (DHG), eicosapentaenoyl ethanolamide (EPA-EA) and eicosapentanoylglycerol (EPG). Furthermore, we outline the lesser known omega-3 eCB-like molecules that arise from the conjugation of omega-3 fatty acids with neurotransmitters serotonin and dopamine - DHA-serotonin (DHA-5HT), DHA-dopamine (DHA-DA), EPA-serotonin (EPA-5HT) and EPA-dopamine (EPA-DA). Additionally, we describe the role of omega-3 eCBs and their derivatives in different disease states, such as pain, inflammation and cancer. Moreover, we detail the formation and potential physiological roles of the oxidative metabolites that arise from the metabolism of omega-3 eCBs by eicosanoid synthesizing enzymes - cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 epoxygenase (CYP450). In summary, we outline the novel findings regarding a growing class of signaling molecules that can control the physiological and pathophysiological processes in the body.

TrpV1 receptor activation rescues neuronal function and network gamma oscillations from Aβ-induced impairment in mouse hippocampus in vitro

Amyloid-β peptide (Aβ) forms plaques in Alzheimer’s disease (AD) and is responsible for early cognitive deficits in AD patients. Advancing cognitive decline is accompanied by progressive impairment of cognition-relevant EEG patterns such as gamma oscillations. The endocannabinoid anandamide, a TrpV1-receptor agonist, reverses hippocampal damage and memory impairment in rodents and protects neurons from Aβ-induced cytotoxic effects. Here, we investigate a restorative role of TrpV1-receptor activation against Aβ-induced degradation of hippocampal neuron function and gamma oscillations. We found that the TrpV1-receptor agonist capsaicin rescues Aβ-induced degradation of hippocampal gamma oscillations by reversing both the desynchronization of AP firing in CA3 pyramidal cells and the shift in excitatory/inhibitory current balance. This rescue effect is TrpV1-receptor-dependent since it was absent in TrpV1 knockout mice or in the presence of the TrpV1-receptor antagonist capsazepine. Our findings provide novel insight into the network mechanisms underlying cognitive decline in AD and suggest TrpV1 activation as a novel therapeutic target.

Preventing acute asthmatic symptoms by targeting a neuronal mechanism involving carotid body lysophosphatidic acid receptors

Asthma accounts for 380,000 deaths a year. Carotid body denervation has been shown to have a profound effect on airway hyper-responsiveness in animal models but a mechanistic explanation is lacking. Here we demonstrate, using a rat model of asthma (OVA-sensitized), that carotid body activation during airborne allergic provocation is caused by systemic release of lysophosphatidic acid (LPA). Carotid body activation by LPA involves TRPV1 and LPA-specific receptors, and induces parasympathetic (vagal) activity. We demonstrate that this activation is sufficient to cause acute bronchoconstriction. Moreover, we show that prophylactic administration of TRPV1 (AMG9810) and LPA (BrP-LPA) receptor antagonists prevents bradykinin-induced asthmatic bronchoconstriction and, if administered following allergen exposure, reduces the associated respiratory distress. Our discovery provides mechanistic insight into the critical roles of carotid body LPA receptors in allergen-induced respiratory distress and suggests alternate treatment options for asthma.

Acute bronchoconstriction is the leading cause of asthmatic sudden death following allergen exposure. The authors show that the systemic increase of LPA following inhaled allergen or bradykinin challenge activates the carotid bodies through TRPV1 and LPA-specific receptors and that systemic TRPV1 and LPA-specific receptor antagonists ameliorate acute bronchoconstriction.

The mucosal surfaces of both eyes are immunologically linked by a neurogenic inflammatory reflex involving TRPV1 and substance P

Immunological interdependence between the two eyes has been reported for the cornea and the retina but not for the ocular mucosal surface. Intriguingly, patients frequently report ocular surface-related symptoms in the other eye after unilateral ocular surgery. Here we show how unilateral eye injuries in mice affect the mucosal immune response of the opposite ocular surface. We report that, despite the lack of lymphatic cross-drainage, a neurogenic inflammatory reflex in the contralateral conjunctiva is sufficient to increase, first, epithelial nuclear factor kappa B signaling, then, dendritic cell maturation, and finally, expansion of effector, instead of regulatory, T cells in the draining lymph node, leading to disrupted ocular mucosal tolerance. We also show that damage to ocular surface nerves is required. Using pharmacological inhibitors and agonists, we identified transient receptor potential vanilloid 1 (TRPV1) channel as the receptor sensing tissue damage in the injured eye and substance P released in the opposite ocular surface as the effector of the sympathetic response. Finally, blocking either step prevented subsequent ocular allergic reactions in the opposite eye in a unilateral corneal alkali burn model. This study demonstrates that both ocular surfaces are immunologically linked and suggests potential therapeutic targets for intervention.

Transcriptomics investigation of thyroid hormone disruption in the olfactory system of the Rana [Lithobates] catesbeiana tadpole

Thyroid hormones (THs) regulate vertebrate growth, development, and metabolism. Despite their importance, there is a need for effective detection of TH-disruption by endocrine disrupting chemicals (EDCs). The frog olfactory system substantially remodels during TH-dependent metamorphosis and the objective of the present study is to examine olfactory system gene expression for TH biomarkers that can evaluate the biological effects of complex mixtures such as municipal wastewater. We first examine classic TH-response gene transcripts using reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) in the olfactory epithelium (OE) and olfactory bulb (OB) of premetamorphic Rana (Lithobates) catesbeiana tadpoles after 48 h exposure to biologically-relevant concentrations of the THs, 3,5,3'-triiodothyronine (T3) and L-thyroxine (T4), or 17-beta estradiol (E2); a hormone that can crosstalk with THs. As the OE was particularly sensitive to THs, further RNA-seq analysis found >30,000 TH-responsive contigs. In contrast, E2 affected 267 contigs of which only 57 overlapped with THs suggesting that E2 has limited effect on the OE at this developmental phase. Gene ontology enrichment analyses identified sensory perception and nucleoside diphosphate phosphorylation as the top affected terms for THs and E2, respectively. Using classic and additional RNA-seq-derived TH-response gene transcripts, we queried TH-disrupting activity in municipal wastewater effluent from two different treatment systems: anaerobic membrane bioreactor (AnMBR) and membrane enhanced biological phosphorous removal (MEBPR). While we observed physical EDC removal in both systems, some TH disruption activity was retained in the effluents. This work lays an important foundation for linking TH-dependent gene expression with olfactory system function in amphibians.

Cnidarian peptide neurotoxins: a new source of various ion channel modulators or blockers against central nervous systems disease

Cnidaria provide the largest source of bioactive peptides for new drug development. The venoms contain enzymes, potent pore-forming toxins and neurotoxins. The neurotoxins can immobilize predators rapidly when discharged via modifying sodium-channel-gating or blocking the potassium channel during the repolarization stage. Most cnidarian neurotoxins remain conserved under the strong influence of negative selection. Neuroactive peptides targeting the central nervous system through affinity with ion channels could provide insight leading to drug treatment of neurological diseases, which arise from ion channel dysfunctions. Although marine resources offer thousands of possible peptides, only one peptide derived from Cnidaria: ShK-186, also named dalazatide, has reached the pharmaceutical market. This review focuses on neuroprotective agents derived from cnidarian neurotoxic peptides.

Capsaicin-enriched diet ameliorates autoimmune neuritis in rats

BACKGROUND

Autoimmune neuropathies are common PNS disorders and effective treatment is challenging. Environmental influence and dietary components are known to affect the course of autoimmune diseases. Capsaicin as pungent component of chili-peppers is common in human nutrition. An influence of capsaicin on autoimmune diseases has been postulated.

METHODS

We tested capsaicin in the animal model of experimental autoimmune neuritis (EAN) in Lewis rat. Rats were immunized with P2-peptide and were treated with capsaicin in different preventive settings. Electrophysiological, histological, and molecular biological analyses of the sciatic nerve were performed to analyze T-cell and macrophage cell count, TRPV1, and cytokine expression. Moreover, FACS analyses including the intestinal immune system were executed.

RESULTS

We observed an immunomodulatory effect of an early preventive diet-concept, where a physiological dosage of oral capsaicin was given 10 days before immunization in EAN. A reduced inflammation of the sciatic nerve was significant detectable clinically, electrophysiologically (CMAPs reduced in control group p < 0.01; increase of nerve conduction blocks in control group p < 0.05), histologically (significant reduction of T-cells, macrophages and demyelination), and at cytokine level. In contrast, this therapeutic effect was missing with capsaicin given from the day of immunization onwards. As possible underlying mechanism, we were able to show changes in the expression of the capsaicin receptor in the sciatic nerve and the small intestine, as well as altered immune cell populations in the small intestine.

CONCLUSION

This is the first report about the immunomodulatory effect of the common nutrient, capsaicin, in an experimental model for autoimmune neuropathies.

Host-mediated effects of phytonutrients in ruminants: A review

Plants produce an extensive array of organic compounds derived from secondary metabolism that may be useful in animal nutrition because of their chemical makeup. These plant-derived bioactive compounds, also referred to as phytonutrients (PN) or phytobiotics, have been shown to express antimicrobial activities against a wide range of bacteria, yeast, and fungi and have been investigated as rumen modifiers in ruminant nutrition. Studies have reported that PN may inhibit deamination of AA and methanogenesis in the rumen and shift fermentation toward propionate and butyrate. Most of the experiments, however, have been conducted in vitro, and responses have been highly variable and inconsistent in animal experiments. In addition, some studies have reported that PN had positive effects on productivity, although rumen fermentation was not affected. Other than antimicrobial effects in the gut, PN are known to bind specific receptors expressed in neurons, intestines, and other cells and exhibit related physiological effects in nonruminants. The receptor-mediated effects include immune responses, oxidative stress, and insulin secretion and activity. Some PN, due to their phenolic nature, are likely less susceptible to microbial degradation in the rumen and may exhibit activities postruminally, similar to their mode of action in nonruminant species. This opens a new area of research in ruminants, including effects of PN on the animal's immune system, postruminal nutrient use, and animal physiology. Although limited, studies with ruminants provide first evidence of PN's regulatory effects on the host responses. For example, PN were reported to regulate immune cells related to adaptive and innate immunity in challenged or nonchallenged dairy cows. Supplementation of PN reduced oxidative stress by decreasing lipid peroxidation and increasing endogenous antioxidants in ruminants. Additionally, insulin secretion and sensitivity were reportedly regulated by PN in dairy cows. The regulatory effects of PN on immunity may be beneficial for immune suppression and inflammation in dairy cows. In addition, PN could positively affect energy partitioning for milk production through their effects on insulin secretion and sensitivity. Further research is needed to elucidate the effect and mode of action of PN on immune function and animal energetics.

Effects of rumen-protected Capsicum oleoresin on immune responses in dairy cows intravenously challenged with lipopolysaccharide

The objective of this experiment was to investigate the effects of rumen-protected Capsicum oleoresin (RPC) on productivity and immune responses including feed intake, milk yield and composition, white and red blood cells, lipid peroxidation, and blood concentration of cortisol, haptoglobin, glucose, and insulin in lactating dairy cows experimentally challenged with lipopolysaccharide (LPS). The experiment was a replicated 3 × 3 Latin square design with 9 multiparous Holstein cows in three 28-d periods. Treatments were 0 (control), 100, and 200 mg of RPC/cow per day, mixed with small portions of the total mixed ration and top-dressed. Bacterial LPS was intravenously administered at 1.0 μg/kg of body weight in the last week of each experimental period, and blood samples were collected at 0, 2, 4, 8, and 24 h after administration. Dry matter intake, milk yield, and white blood cells including neutrophils, lymphocytes, monocytes, and eosinophils were decreased, and rectal temperature, hemoglobin, and serum concentrations of cortisol and haptoglobin were increased by LPS. Red blood cells, platelets, and plasma concentration of thiobarbituric acid reactive substances were not affected by LPS. Dry matter intake, milk yield, and milk composition in the 5 d post-LPS challenge were not affected by RPC. Rectal temperature, white blood cells, red blood cells, hemoglobin, and platelets were also not affected by RPC. Compared with the control, RPC tended to decrease cortisol at 2 h following LPS challenge and decreased haptoglobin concentration in serum across sampling points. Concentration of thiobarbituric acid reactive substances in plasma was decreased by RPC at 24 h post-LPS challenge. Glucose and insulin were not affected by RPC, but serum insulin concentration at 8 h was lowered by RPC compared to the control. Collectively, RPC had no or subtle effects on feed intake, milk yield and composition, rectal temperature, white and red blood cells, and serum glucose and insulin concentration in dairy cows challenged by LPS. However, RPC tended to decrease cortisol and decreased concentrations of haptoglobin and thiobarbituric acid reactive substances in blood following LPS challenge. Data suggest that dietary supplementation of RPC may modulate acute phase responses induced by bacterial infection in lactating dairy cows.

Contemporary views on inflammatory pain mechanisms: TRPing over innate and microglial pathways

Tissue injury, whether by trauma, surgical intervention, metabolic dysfunction, ischemia, or infection, evokes a complex cellular response (inflammation) that is associated with painful hyperalgesic states. Although in the acute stages it is necessary for protective reflexes and wound healing, inflammation may persist well beyond the need for tissue repair or survival. Prolonged inflammation may well represent the greatest challenge mammalian organisms face, as it can lead to chronic painful conditions, organ dysfunction, morbidity, and death. The complexity of the inflammatory response reflects not only the inciting event (infection, trauma, surgery, cancer, or autoimmune) but also the involvement of heterogeneous cell types including neuronal (primary afferents, sensory ganglion, and spinal cord), non-neuronal (endothelial, keratinocytes, epithelial, and fibroblasts), and immune cells. In this commentary, we will examine 1.) the expression and regulation of two members of the transient receptor potential family in primary afferent nociceptors and their activation/regulation by products of inflammation, 2.) the role of innate immune pathways that drive inflammation, and 3.) the central nervous system’s response to injury with a focus on the activation of spinal microglia driving painful hyperalgesic states.

Multi-inhibitor prodrug constructs for simultaneous delivery of anti-inflammatory agents to mustard-induced skin injury

The molecular pathology of sulfur mustard injury is complex, with at least nine inflammation-related enzymes and receptors upregulated in the zone of the insult. A new approach wherein inhibitors of these targets have been linked by hydrolyzable bonds, either one to one or via separate preattachment to a carrier molecule, has been shown to significantly enhance the therapeutic response compared with the individual agents. This article reviews the published work of the authors in this drug development domain over the last 8 years.

TRPV1 antagonism by capsazepine modulates innate immune response in mice infected with Plasmodium berghei ANKA

Thousands of people suffer from severe malaria every year. The innate immune response plays a determinant role in host's defence to malaria. Transient receptor potential vanilloid 1 (TRPV1) modulates macrophage-mediated responses in sepsis, but its role in other pathogenic diseases has never been addressed. We investigated the effects of capsazepine, a TRPV1 antagonist, in malaria. C57BL/6 mice received 10(5) red blood cells infected with Plasmodium berghei ANKA intraperitoneally. Noninfected mice were used as controls. Capsazepine or vehicle was given intraperitoneally for 6 days. Mice were culled on day 7 after infection and blood and spleen cell phenotype and activation were evaluated. Capsazepine decreased circulating but not spleen F4/80(+)Ly6G(+) cell numbers as well as activation of both F4/80(+)and F4/80(+)Ly6G(+) cells in infected animals. In addition, capsazepine increased circulating but not spleen GR1(+) and natural killer (NK) population, without interfering with natural killer T (NKT) cell numbers and blood NK and NKT activation. However, capsazepine diminished CD69 expression in spleen NKT but not NK cells. Infection increased lipid peroxidation and the release of TNFα and IFNγ, although capsazepine-treated group exhibited lower levels of lipid peroxidation and TNFα. Capsazepine treatment did not affect parasitaemia. Overall, TRPV1 antagonism modulates the innate immune response to malaria.