9-cis-Retinoic acid induces a distinct regulatory dendritic cell phenotype that modulates murine delayed-type allergy

Comparison of the chemical constituents of Saposhnikoviae Radix associated with three different growth patterns and its therapeutic effect against atopic dermatitis

ETHNOPHARMACOLOGICAL RELEVANCE

Saposhnikoviae Radix (SR) was initially documented in Shennong Bencao Jing classics for its properties in dispelling wind, dissolving surface, relieving pain, and alleviating spasms. This herb is commonly used in traditional Chinese medicine to address conditions that affect the body's surface, by aiding in the expulsion of pathogens from the surface and alleviating pain associated with the immune response. Atopic dermatitis (AD) is a prevalent allergic skin disorder, and the therapeutic effects of SR in dispelling wind and relieving the body's surface are consistent with the clinical symptoms commonly observed in AD.

AIM OF THE STUDY

The anti-AD effects of SR were examined under three different growth patterns to identify active pharmacodynamic compounds. The results provide insight into the clinical efficacy of wild and cultivated SR.

MATERIALS AND METHODS

The efficacy of wild, wild-simulated, and cultivated SR was assessed in a mouse model of AD. In addition, the effects of wild and varying doses of cultivated SR were evaluated in mice with short-term AD symptoms. GC-MS and UPLC-MS/MS were used to analyze the chemical components of the three SR treatments and molecular docking was used to identify active components.

RESULTS

A mouse model of AD was used to assess the pharmacodynamic effects of SR prepared by three different cultivation methods. The study found that all three SR preparations improved phenotypic markers and histopathological features in the AD mouse model. The efficacy of wild SR and wild-simulated SR was similar, although there was a significant difference between wild and cultivated SR. Both wild SR and various doses of cultivated SR ameliorated skin injuries and reduced inflammation in serum and skin tissues. Furthermore, skin thickness, inflammatory cells, mast cell infiltration, and IL-33 expression improved following treatment. Notably, wild SR, double-cultivated SR, and triple-cultivated SR demonstrated significant therapeutic effects. An analysis using GC-MS revealed the presence of 55, 52, and 43 volatile oils in the three SR preparations, with more common components observed between wild and wild-simulated SR. Fewer common components were evident between cultivated and wild SR. UPLC-MS/MS analysis identified a total of 37 compounds, with larger relative peak areas observed for the chromogenic ketones. Molecular docking studies revealed that certain compounds, such as n-propyl 9,12-octadecadienoate, (E)-9-octadecenoic acid ethyl ester, and various chromogenic ketones, such as cimifugin, 5-O-methyIvisamminol, hamaudol, 3'-O-acetylhamaudol, 3'-O-angeloyhamandol, adenosine and farnesylaceton, may be the major substances that distinguish the activities of SR with three different growth patterns.

CONCLUSION

Variations in the anti-AD efficacy of SR with three growth patterns were identified, and their chemical composition differences were determined. These findings suggest that increasing the dosage of cultivated SR could potentially be a viable clinical alternative for atopic dermatitis treatment.

Gut microbiota-derived lipid metabolites facilitate regulatory T cell differentiation

Commensal bacteria-derived metabolites are critical in regulating the host immune system. Although the impact of gut microbiota-derived hydrophilic metabolites, such as short-chain fatty acids, on immune cell functions and development has been well documented, the immunomodulatory effects of gut microbiota-derived lipids are still of interest. Here, we report that lipid extracts from the feces of specific-pathogen-free (SPF), but not germ-free (GF), mice showed regulatory T (Treg)-cell-inducing activity. We conducted RP-HPLC-based fractionation and liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based lipidome profiling and identified two bioactive lipids, 9,10-dihydroxy-12Z-octadecenoic acid (9,10-DiHOME) and all-trans retinoic acid (atRA), with Treg-inducing activity in vitro. The luminal abundance of 9,10-DiHOME in the large intestine was significantly decreased by dextran sulfate sodium (DSS)-induced colitis, indicating that 9,10-DiHOME may be a potential biomarker of colitis. These observations implied that commensal bacteria-derived lipophilic metabolites might contribute to Treg development in the large intestine.

Association of vitamin A supplementation with immune-related allergic diseases: A meta-analysis

BACKGROUND

Allergic diseases are type I hypersensitivity reactions mediated by various allergens. The most common allergic diseases include allergic rhinitis, allergic asthma, allergic dermatitis, and allergic conjunctivitis. The incidence of allergic diseases has been increasing in the recent past, and allergen avoidance and adoption of desensitization treatment can significantly decrease the incidence of allergic diseases. Previous studies have explored the association between vitamin A supplementation and allergic diseases; however, the results are inconsistency. The aim of the present study was to evaluate the association between vitamin A supplementation and allergic diseases, with a focus on atopy and wheezing.

METHODS

Articles reporting randomized controlled trials (RCTs) on the association of vitamin A supplementation and allergic diseases were retrieved from PubMed, Embase, Web of science, and China National Knowledge Infrastructure database from inception of to November 15, 2021. STATA 12.0 software was used for meta-analysis, sensitivity analysis and analysis of publication bias.

RESULTS

Seven studies comprising 2201 participants met the inclusion criteria and were included in the meta-analysis. The findings showed that vitamin A supplementation was associated with increased risk of atopy in young females compared with the placebo [RR = 1.70, 95% confidence interval (1.20, 2.41), P = 0.171, I 2 = 43.4% fixed effect model]. The frequency of delayed atopy among adults was associated with vitamin A supplementation (MD = 0.46, 95% CI = 0.04, 0.88). Analysis showed no significant association between vitamin A supplementation with incidence of wheezing in children [RR = 1.40, 95% CI (0.49, 3.98), P = 0.018, I 2 = 82.1% random effect model]. Sensitivity and publication bias analysis showed that each individual study did not affect the combined results and there was no significant publication bias among the studies.

CONCLUSION

The findings showed that vitamin A supplementation is associated with increased risk of atopy but no correlation was observed with the incidence of wheezing. The results of this meta-analysis provide evidence for effective management of fibrosis. More studies should be conducted to verify the results.

Regulatory Dendritic Cells, T Cell Tolerance, and Dendritic Cell Therapy for Immunologic Disease

Dendritic cells (DC) are antigen-presenting cells that can communicate with T cells both directly and indirectly, regulating our adaptive immune responses against environmental and self-antigens. Under some microenvironmental conditions DC develop into anti-inflammatory cells which can induce immunologic tolerance. A substantial body of literature has confirmed that in such settings regulatory DC (DCreg) induce T cell tolerance by suppression of effector T cells as well as by induction of regulatory T cells (Treg). Many in vitro studies have been undertaken with human DCreg which, as a surrogate marker of antigen-specific tolerogenic potential, only poorly activate allogeneic T cell responses. Fewer studies have addressed the abilities of, or mechanisms by which these human DCreg suppress autologous effector T cell responses and induce infectious tolerance-promoting Treg responses. Moreover, the agents and properties that render DC as tolerogenic are many and varied, as are the cells’ relative regulatory activities and mechanisms of action. Herein we review the most current human and, where gaps exist, murine DCreg literature that addresses the cellular and molecular biology of these cells. We also address the clinical relevance of human DCreg, highlighting the outcomes of pre-clinical mouse and non-human primate studies and early phase clinical trials that have been undertaken, as well as the impact of innate immune receptors and symbiotic microbial signaling on the immunobiology of DCreg.

Metabolomics and Proteomics Reveal the Variation of Substances in Apheresis Platelets during Storage and Their Effects on Cancer Cell Proliferation

INTRODUCTION

Apheresis platelets (APs) are clinically and crucially important in the prevention and treatment of bleeding in patients with thrombocytopenia or cancer. However, few researchers have addressed the variation of supernatant metabolites and exosome proteins in APs during storage and their effects on cancer cell proliferation.

OBJECTIVE

This study was designed to explore the change rules of the metabolites and exosomal proteins of APs during storage and their effects on cancer cell proliferation.

METHODS

Metabolomics and proteomics were separately applied to analyze the variation of AP supernatant metabolites and exosomal proteins between freshly prepared day-0 and day-5 terminal-stored APs. Cell counting kit (CCK)-8 assay was performed to detect the effects of AP supernatants and exosomes on the proliferation of cancer cells.

RESULTS

We found that the supernatant metabolites and exosomal proteins in APs were significantly different on day 0 and day 5, and that many differential metabolites and exosomal proteins were associated with cancer characteristics. Furthermore, the day-5 AP supernatants had a greater inhibition of the proliferation of K562, HepG2, and HCT116 cancer cells, but the day-5 AP exosomes had no significant effect on the proliferation of these cancer cells.

CONCLUSION

The variant terminal-stored AP supernatants may inhibit the proliferation of cancer cells but the variant terminal AP exosomes have no effect on cancer cell proliferation.

Tetracycline use in treating osteoarthritis: a systematic review

BACKGROUND AND AIMS

The purpose of the review was to synthesize the current literature regarding tetracyclines in the treatment of osteoarthritis.

METHODS

Using multiple databases, a systematic review was performed with customized search terms crafted to identify studies examining doxycycline or minocycline in the treatment of osteoarthritis. Results were classified into basic science mechanistic studies, in vivo animal studies, and human clinical trials. A total of 1446 potentially relevant studies were reviewed, and after exclusion criteria were applied, 23 investigations were included in the final analysis.

RESULTS

From 12 basic science mechanistic studies, we report on three main mechanisms by which tetracyclines may exert benefit in osteoarthritis progression: matrix metalloproteinase inhibition, immunomodulation, and nitric oxide synthase inhibition. Seven animal studies showed generally encouraging results. Four articles reported human clinical studies, showing mixed results in the treatment of osteoarthritis, potentially related to the choice of patient population, primary outcomes, and timing of treatment.

CONCLUSION

Tetracyclines have the potential to benefit osteoarthritis patients via multiple mechanisms. Further study is warranted to examine the optimal dose and timing of tetracycline treatment in osteoarthritis.

Illuminating the Role of Vitamin A in Skin Innate Immunity and the Skin Microbiome: A Narrative Review

Vitamin A is a fat-soluble vitamin that plays an important role in skin immunity. Deficiencies in Vitamin A have been linked to impaired immune response and increased susceptibility to skin infections and inflammatory skin disease. This narrative review summarizes recent primary evidence that elucidates the role of vitamin A and its derivatives on innate immune regulators through mechanisms that promote skin immunity and sustain the skin microbiome.

Intranasal delivery of 9-cis retinoic acid reduces beta-amyloid deposition via inhibiting astrocyte-mediated inflammation

Alzheimer's disease (AD) is associated with the accumulation and deposition of a beta-amyloid (Αβ) peptide in the brain, resulting in increased neuroinflammation and synaptic dysfunction. Intranasal delivery of targeted drugs to the brain represents a noninvasive pathway that bypasses the blood-brain barrier and minimizes systemic exposure. The aim of this study was to evaluate the therapeutic effect of intranasally delivered 9-cis retinoic acid (RA) on the neuropathology of an AD mouse model. Herein, we observed dramatically decreased Αβ deposition in the brains of amyloid precursor protein (APP) and presenilin 1 (PS1) double-transgenic mice (APP/PS1) treated intranasally with 9-cis RA for 4 weeks compared to that in the brains of vehicle-treated mice. Importantly, intranasal delivery of 9-cis RA suppressed Αβ-associated astrocyte activation and neuroinflammation and ultimately restored synaptic deficits in APP/PS1 transgenic mice. These results support the critical roles of Αβ-associated neuroinflammation responses to synaptic deficits, particularly during the deposition of Αβ. Our findings provide strong evidence that intranasally delivered 9-cis RA attenuates neuronal dysfunction in an AD mouse model and is a promising therapeutic strategy for the prevention and treatment of AD.

Role of osteopontin in dendritic cell shaping of immune responses

Osteopontin (OPN) is a pleiotropic cytokine produced both by immune and non-immune cells and active on different cellular targets. OPN production has been associated with several pathological conditions, including autoimmune diseases (e.g. lupus, multiple sclerosis and rheumatoid arthritis) and cancer. Emerging evidence suggests that the role of OPN has been underestimated, as it seems to be working at multiple levels of immune regulation, such as the shaping of T cell effector responses, the regulation of the tumor microenvironment, and the functional interaction with mesenchymal stromal cells. In this context, dendritic cells (DCs) play a crucial role being both an important source and a cellular target for OPN action. DC family is composed by several cell subsets endowed with specific immune functions. OPN exerts its biological functions through multiple receptors and is produced in different intracellular and secreted forms. OPN production by DC subsets is emerging as a crucial mechanism of regulation in normal and pathological conditions and starts to be exploited as a therapeutic target. This review will focus on the role of DC-derived OPN in shaping immune response and on the complex role of this cytokines in the regulation in immune response.

Chemical-induced contact allergy: from mechanistic understanding to risk prevention

Chemical allergens are small molecules able to form a sensitizing complex once they bound to proteins. One of the most frequent manifestations of chemical allergy is contact hypersensitivity, which can have serious impact on quality of life. Allergic contact dermatitis is a predominantly CD8 + T cell-mediated immune disease, resulting in erythema and eczema. Chemical allergy is of considerable importance to the toxicologist, who has the responsibility of identifying and characterizing the allergenic potential of chemicals, and estimating the risk they pose to human health. This review aimed at exploring the phenomena of chemical-induced contact allergy starting from a mechanistic understanding, immunoregulatory mechanisms, passing through the potency of contract allergen until the hazard identification, pointing out the in vitro models for assessing contact allergen-induced cell activation and the risk prevention.