The key player in the pathogenesis of environmental influence of systemic lupus erythematosus: Aryl hydrocarbon receptor

The Impact of Social Inequities on Presentation of Juvenile-Onset Systemic Lupus Erythematosus at a Large Tertiary Center

OBJECTIVE

The prevalence of juvenile-onset systemic lupus erythematosus (JSLE) differs by race/ethnicity with environmental, genetic, and social factors implicated in disease severity and outcomes. Yet, the role of social determinants of health (SDoH) in disease presentation is not well understood. We hypothesized that in an urban center with a large, diverse catchment area, SDoH influence the severity of JSLE at diagnosis.

METHODS

We completed an institutional review board-approved medical record review of children newly diagnosed with JSLE between January 1, 2018, and May 31, 2022, at Texas Children's Hospital in Houston, TX. We collected demographic data, clinical severity measures, and SDoH variables such as Area Deprivation Index (ADI), insurance status, pollution burden, and food accessibility. Statistical analysis to compare SDoH with JSLE severity included Kruskal-Wallis test, Fisher exact test, and univariable and multivariable regression.

RESULTS

Mean diagnosis age for 136 patients was 13.4 years, with 82.4% female, 52.9% Hispanic, and 25.7% non-Hispanic (NH) Black. One-third of patients did not have a documented primary care provider, and one-third preferred non-English language. We found NH Black patients had worse clinical severity measures, with highest Systemic Lupus Erythematosus Disease Activity Index and more central nervous system involvement and cyclophosphamide therapy. Uninsured and publicly insured patients were more likely to use inpatient resources at diagnosis and live in neighborhoods with higher pollution levels and higher ADI. Hispanic patients reside in communities with higher ADI scores and limited access to supermarkets.

CONCLUSION

In children with JSLE from a large urban catchment area, we observed significant association of nonmodifiable (race/ethnicity) and modifiable (insurance status, access to care, food accessibility) factors on disease severity at presentation.

The Complex Role of Gut Microbiota in Systemic Lupus Erythematosus and Lupus Nephritis: From Pathogenetic Factor to Therapeutic Target

The role of gut microbiota (GM) and intestinal dysbiosis in triggering the onset and/or modulating the severity and progression of lupus nephritis (LN) has been the object of intense research over the last few years. Some alterations at the phyla level, such as the abundance of Proteobacteria and reduction in Firmicutes/Bacteroidetes (F/B) ratio and in α-diversity have been consistently reported in systemic lupus erythematosus (SLE), whereas a more specific role has been ascribed to some species (Bacteroides thetaiotaomicron and Ruminococcus gnavus) in LN. Underlying mechanisms include microbial translocation through a "leaky gut" and subsequent molecular mimicry, immune dysregulation (alteration of IFNγ levels and of balance between Treg and Th17 subsets), and epigenetic interactions. Levels of bacterial metabolites, such as butyrate and other short-chain fatty acids (SCFAs), appear to play a key role in modulating LN. Beyond bacterial components of GM, virome and mycobiome are also increasingly recognized as important players in the modulation of an immune response. On the other hand, microbiota-based therapy appears promising and includes diet, prebiotics, probiotics, symbiotics, and fecal microbiota transplantation (FMT). The modulation of microbiota could correct critical alterations, such as F/B ratio and Treg/Th17 imbalance, and blunt production of autoantibodies and renal damage. Despite current limits, GM is emerging as a powerful environmental factor that could be harnessed to interfere with key mechanisms leading to SLE, preventing flares and organ damage, including LN. The aim of this review is to provide a state-of-the-art analysis of the role of GM in triggering and modulating SLE and LN on the one hand, while exploring possible therapeutic manipulation of GM to control the disease on the other hand.

Aryl hydrocarbon receptor: current perspectives on key signaling partners and immunoregulatory role in inflammatory diseases

The aryl hydrocarbon receptor (AhR) is a versatile environmental sensor and transcription factor found throughout the body, responding to a wide range of small molecules originating from the environment, our diets, host microbiomes, and internal metabolic processes. Increasing evidence highlights AhR's role as a critical regulator of numerous biological functions, such as cellular differentiation, immune response, metabolism, and even tumor formation. Typically located in the cytoplasm, AhR moves to the nucleus upon activation by an agonist where it partners with either the aryl hydrocarbon receptor nuclear translocator (ARNT) or hypoxia-inducible factor 1β (HIF-1β). This complex then interacts with xenobiotic response elements (XREs) to control the expression of key genes. AhR is notably present in various crucial immune cells, and recent research underscores its significant impact on both innate and adaptive immunity. This review delves into the latest insights on AhR's structure, activating ligands, and its multifaceted roles. We explore the sophisticated molecular pathways through which AhR influences immune and lymphoid cells, emphasizing its emerging importance in managing inflammatory diseases. Furthermore, we discuss the exciting potential of developing targeted therapies that modulate AhR activity, opening new avenues for medical intervention in immune-related conditions.

Kynurenines as a Novel Target for the Treatment of Inflammatory Disorders

This review discusses the potential of targeting the kynurenine pathway (KP) in the treatment of inflammatory diseases. The KP, responsible for the catabolism of the amino acid tryptophan (TRP), produces metabolites that regulate various physiological processes, including inflammation, cell cycle, and neurotransmission. These metabolites, although necessary to maintain immune balance, may accumulate excessively during inflammation, leading to systemic disorders. Key KP enzymes such as indoleamine 2,3-dioxygenase 1 (IDO1), indoleamine 2,3-dioxygenase 2 (IDO2), tryptophan 2,3-dioxygenase (TDO), and kynurenine 3-monooxygenase (KMO) have been considered promising therapeutic targets. It was highlighted that both inhibition and activation of these enzymes may be beneficial, depending on the specific inflammatory disorder. Several inflammatory conditions, including autoimmune diseases, for which modulation of KP activity holds therapeutic promise, have been described in detail. Preclinical studies suggest that this modulation may be an effective treatment strategy for diseases for which treatment options are currently limited. Taken together, this review highlights the importance of further research on the clinical application of KP enzyme modulation in the development of new therapeutic strategies for inflammatory diseases.

Systemic lupus erythematosus therapeutic strategy: From immunotherapy to gut microbiota modulation

Systemic lupus erythematosus (SLE) is characterized by a systemic dysfunction of the innate and adaptive immune systems, leading to an attack on healthy tissues of the body. During the development of SLE, pathogenic features, such as the formation of autoantibodies to self-nuclear antigens, caused tissue damage including necrosis and fibrosis, with an increased expression of type Ⅰ interferon (IFN) regulated genes. Treatment of lupus with immunosuppressants and glucocorticoids, which are used as the standard therapy, is not effective enough and causes side effects. As an alternative, more effective immunotherapies have been developed, including monoclonal and bispecific antibodies that target B cells, T cells, co-stimulatory molecules, cytokines or their receptors, and signaling molecules. Encouraging results have been observed in clinical trials with some of these therapies. Furthermore, a chimeric antigen receptor T cells (CAR-T) therapy has emerged as the most effective, safe, and promising treatment option for SLE, as demonstrated by successful pilot studies. Additionally, emerging evidence suggests that gut microbiota dysbiosis may play a significant role in the severity of SLE, and the use of methods to normalize the gut microbiota, particularly fecal microbiota transplantation (FMT), opens up new opportunities for effective treatment of SLE.

Comparative analysis of microbial composition and functional characteristics in dental plaque and saliva of oral cancer patients

BACKGROUND

The oral cavity is home to various ecological niches, each with its own unique microbial composition. Understanding the microbial communities and gene composition in different ecological niches within the oral cavity of oral cancer (OC) patients is crucial for determining how these microbial populations contribute to disease progression.

METHODS

In this study, saliva and dental plaque samples were collected from patients with OC. Metagenomic sequencing was employed to analyze the microbial community classification and functional composition of the different sample groups.

RESULTS

The results of the study revealed significant differences in both the function and classification of microbial communities between saliva and dental plaque samples. The diversity of microbial species in saliva was found to be higher compared to  that in plaque samples. Notably, Actinobacteria were enriched in the dental plaque of OC patients. Furthermore, the study identified several inter-group differential marker species, including Prevotella intermedia, Haemophilus parahaemolyticus, Actinomyces radius, Corynebacterium matruchitii, and Veillonella atypica. Additionally, 1,353 differential genes were annotated into 23 functional pathways. Interestingly, a significant correlation was observed between differentially labeled species and Herpes simplex virus 1 (HSV-1) infection, which may be related to the occurrence and development of cancer.

CONCLUSIONS

Significant differences in the microbial and genetic composition of saliva and dental plaque samples were observed in OC patients. Furthermore, pathogenic bacteria associated with oral diseases were predominantly enriched in saliva. The identification of inter-group differential biomarkers and pathways provide insights into the relationship between oral microbiota and the occurrence and development of OC.

Topical Application of Skin Biome Care Regimen Containing Live Cultures and Ferments of Cutibacterium acnes defendens strain XYCM42 and the Impact on Clinical Outcomes Following Microneedle-induced Skin Remodeling

Background

The skin, our body's largest organ, hosts a complex microbiome that plays a pivotal role in maintaining health and protecting against pathogens. Even slight disruptions to this delicate balance can influence skin health and disease. Among the diverse microbial community, Cutibacterium acnes (C. acnes) subspecies defendens is known for its positive contribution to skin health. However, the interaction between living microbe probiotics and wound healing after aesthetic procedures, such as microneedling, remains unexplored.

Methods

Our study included 40 participants with acne scars who underwent four microneedling sessions spaced three weeks apart. They were randomly assigned to Group 1, receiving a regimen with live C. acnes defendens strain XYCM42, or Group 2, following a conventional skincare routine with a cleanser, moisturizer, and sunscreen. Our study assessed various endpoints, including the Clinician's Global Aesthetic Improvement Scale (CGAIS), clinical safety, improvement in acne scars using Goodman and Baron's Qualitative and Quantitative Acne Scars Grading Scale and Subject's Global Aesthetic Improvement Scale (SGAIS).

Results

Our analysis of live and photo grading data for CGAIS unveiled a statistically significant difference between the two groups, with Group 1 (XYCM42-based regimen) showing remarkable improvement. A similar positive trend was observed in the photo grading for CGAIS. Additionally, participant diaries indicated that Group 1 experienced a faster decline in posttreatment parameters, including erythema, swelling, burning/tingling, and itching.

Conclusion

Integrating a microbiome-optimized, probiotic XYCM42-based regimen with microneedling demonstrated a high safety profile and enhanced treatment outcomes. These findings mark a milestone in aesthetic dermatology, supporting innovative microbiome-based approaches to improve skin health and aesthetics.

Exploring the Complex Relationship Between Microbiota and Systemic Lupus Erythematosus

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by various autoantibodies and multi-organ. Microbiota dysbiosis in the gut, skin, oral, and other surfaces has a significant impact on SLE development. This article summarizes relevant research and provides new microbiome-related strategies for exploring the mechanisms and treating patients with SLE.

RECENT FINDINGS

SLE patients have disruptions in multiple microbiomes, with the gut microbiota (bacteria, viruses, and fungi) and their metabolites being the most thoroughly researched. This dysbiosis can promote SLE progression through mechanisms such as the leaky gut, molecular mimicry, and epigenetic regulation. Notwithstanding study constraints on the relationship between microbiota and SLE, specific interventions targeting the gut microbiota, such as probiotics, dietary management, and fecal microbiota transplantation, have emerged as promising SLE therapeutics.

Role of Aryl Hydrocarbon Receptor and Oxidative Stress in the Regioselective Toxicities of Hydroxychrysenes in Embryonic Japanese Medaka (Oryzias latipes)

Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) are environmental contaminants that can be created through oxidation of parent PAHs. Previous studies have found that 2-hydroxychrysene (2-OHCHR) caused anemia in embryonic Japanese medaka whereas 6-hydroxychrysene (6-OHCHR) did not, an example of regioselective toxicity. Anemia was prevented by cytochrome P450 (CYP) inhibition, which reduced the formation of the potential oxidatively active metabolite, 1,2-catechol, from 2-OHCHR. 2-OHCHR has also been found to be a four-fold more potent aryl hydrocarbon receptor (AhR) agonist compared with 6-OHCHR. These findings led us to hypothesize that AhR activation and/or oxidative stress play an important role in 2-OHCHR toxicity. Although treatments with the AhR agonists polychlorinated biphenyl (PCB)126 and 2-methoxychrysene (2-MeOCHR) did not cause significant toxicity, pretreatments with the AhR antagonist, CH-223191, reduced anemia by 97.2 ± 0.84% and mortality by 96.6 ± 0.69%. Aryl hydrocarbon receptor inhibition by the antagonist was confirmed by significant reductions (91.0 ± 9.94%) in induced ethoxyresorufin-O-deethylase activity. Thiobarbituric acid reactive substances concentrations were 32.9 ± 3.56% higher (p < 0.05) in 2-OHCHR treatments at 100 hours postfertilization compared with controls. Staining 2-OHCHR-treated embryos with the reactive oxygen species (ROS) scavenger 2',7'-dichlorofluorescin diacetate revealed 32.6 ± 2.69% of 2-OHCHR-treated embryos exhibiting high concentrations of ROS in caudal tissues, which is a site for embryonic hematopoiesis in medaka. Pretreatment with antioxidants, N-acetylcysteine (NAC) or vitamin E (Vit E) significantly reduced 2-OHCHR-induced anemia (NAC: 80.7 ± 1.12% and Vit E: 99.1 ± 0.43%) and mortality (NAC: 67.1 ± 1.69% and Vit E: 98.9 ± 0.66%). These results indicate that AhR may mediate 2-OHCHR toxicity through canonical signaling by up-regulating CYP1, enhancing the formation of reactive metabolites of 2-OHCHR that generate ROS within caudal hematopoietic tissues, potentially disrupting hematopoiesis, leading to anemia and subsequent mortality. Environ Toxicol Chem 2023;42:698-706. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.