Therapeutic Potential of Targeting the Th17/Treg Axis in Autoimmune Disorders

Role of miRNAs in T-cell activation and Th17/Treg-cell imbalance in acquired aplastic anemia

BACKGROUND

Altered T-cell repertoire with an aberrant T-cell activation and imbalance of the Th17/Treg cells has been reported in acquired aplastic anemia (aAA). miRNAs are well known to orchestrate T-cell activation and differentiation, however, their role in aAA is poorly characterized. The study aimed at identifying the profile of miRNAs likely to be involved in T-cell activation and the Th17/Treg-cell imbalance in aAA, to explore newer therapeutic targets.

METHODS

Five milliliters peripheral blood samples from 30 patients of aAA and 15 healthy controls were subjected to flow cytometry for evaluating Th17- and Treg-cell subsets. The differential expression of 7 selected miRNAs viz; hsa-miR-126-3p, miR-146b-5p, miR-155-5p, miR-16, miR-17, miR-326, and miR-181c was evaluated in the PB-MNCs. Expression analysis of the miRNAs was performed using qRT-PCR and fold change was calculated by 2-ΔΔCt method. The alterations in the target genes of deregulated miRNAs were assessed by qRT-PCR. The targets studied included various transcription factors, cytokines, and downstream proteins.

RESULTS

The absolute CD3+ lymphocytes were significantly elevated in the PB of aAA patients when compared with healthy controls (p < 0.0035), however, the CD4:CD8 ratio was unperturbed. Th17: Treg-cell ratio was altered in aAA patients (9.1 vs. 3.7%, p value <0.05), which correlated positively with disease severity and the PNH positive aAA. Across all severities of aAA, altered expression of the 07 miRNAs was noted in comparison to controls; upregulation of miR-155 (FC-2.174, p-value-0.0001), miR-146 (FC-2.006, p-value-0.0001), and miR-17 (FC-3.1, p-value-0.0001), and downregulation of miR-126 (FC-0.329, p-value-0.0001), miR-181c (FC-0.317, p-value-0.0001), miR-16 (FC-0.348, p-value-0.0001), and miR-326 (FC-0.334, p-value-0.0001). Target study for these miRNAs revealed an increased expression of transcription factors responsible for Th1 and Th17 differentiation (T-bet, RORϒt, IL-17, IL-6, and IFN-ϒ), T-cell activation (NFκB, MYC, and PIK3R2), downregulation of FOX-P3, and other regulatory downstream molecules like SHIP-1, ETS-1, IRAK-1, TRAF-6, and PTEN.

CONCLUSION

The study for the first time highlights the plausible role of different miRNAs in deregulating the Th17/Treg-cell imbalance in aAA, and comprehensively suggest the role of altered NF-kB and mTOR pathways in aAA. The axis may be actively explored for development of newer therapeutic targets in aAA.

The Th1/Th2 paradigm: A misrepresentation of helper T cell plasticity

For decades, the Th1/2 paradigm has been used to classify immune responses as either Th1 or Th2-biased. However, in recent years, a staggering amount of evidence has emerged to support rejection of the classical Th1/Th2 paradigm, such as the discoveries of new helper T cell subsets, helper T cell plasticity and protective mixed-Th1/Th2 responses. This opinion piece investigates the shortcomings of classical Th1/Th2 paradigm in the context of recent works, with the goal of facilitating the development of newer models to represent the diversity of Th cells.

Inhibition of cIAP1/2 reduces RIPK1 phosphorylation in pulmonary endothelial cells and alleviate sepsis-induced lung injury and inflammatory response

Acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) is a severe complication of sepsis characterized by acute respiratory distress, hypoxemia, and diffuse bilateral pulmonary infiltrates. The regulation of RIPK1 is an important part of the inflammatory response, and cIAP1/2 serves as the E3 ubiquitin ligase for RIPK1. In this study, we investigated the effect and mechanism of cIAP1/2 inhibition on sepsis-induced lung injury. Our results showed that cIAP1/2 inhibition can alleviate sepsis-induced lung injury and reduce the inflammatory response, which is accompanied by downregulation of RIPK1 phosphorylation and ubiquitination. Additionally, cIAP1/2 inhibition led to the up-regulation of programmed cell death, including apoptosis, necroptosis, and pyroptosis, and inhibiting these three cell death pathways can further reduce the inflammatory response, which is similar to the recently discovered programmed cell death pathway PANoptosis. Our findings suggest that cIAP1/2 and PANoptosis inhibition may be a new strategy for treating sepsis-induced lung injury and provide important references for further exploring the mechanism of sepsis-induced lung injury and identifying new therapeutic targets.

Single-cell transcriptome revealed dysregulated RNA-binding protein expression patterns and functions in human ankylosing spondylitis

Objective

To explore the expression characteristics and regulatory patterns of RBPs in different immune cell types of AS, and to clarify the potential key role of RBPs in the occurrence and development of AS disease.

Methods

PBMC sample data from scRNA-seq (HC*29, AS*10) and bulk RNA-seq (NC*3, AS*5) were selected for correlation analysis.

Results

(1) Compared with the HC group, the numbers of B, DC (dendritic cells), CD14+ Mono and CD8+ T cells were increased in AS group, while the numbers of platelet (platelets), CD8+ NKT, CD16+ Mono (non-classical monocytes), Native CD4+ T and NK were decreased. (2) Through the analysis of RBP genes in B cells, some RBPs were found to play an important role in B cell differentiation and function, such as DDX3X, SFPQ, SRRM1, UPF2. (3) It may be related to B-cell receptor, IgA immunity, NOD-like receptor and other signaling pathways; Through the analysis of RBP genes in CD8+ T cells, some RBPs that play an important role in the immune regulation of CD8+ T were found, such as EIF2S3, EIF4B, HSPA5, MSL3, PABPC1 and SRSF7; It may be related to T cell receptor, TNF, IL17 and other signaling pathways. (4) Based on bulk RNA-seq, it was found that compared with HC and AS patients, differentially expressed variable splicing genes (RASGs) may play an important role in the occurrence and development of AS by participating in transcriptional regulation, protein phosphorylation and ubiquitination, DNA replication, angiogenesis, intracellular signal transduction and other related pathways.

Conclusion

RBPs has specific expression characteristics in different immune cell types of AS patients, and has important regulatory functions. Its abnormal expression and regulation may be closely related to the occurrence and development of AS.

Cerebral malaria pathogenesis: Dissecting the role of CD4+ and CD8+ T-cells as major effectors in disease pathology

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum (P. falciparum) infection, with complex pathogenesis involving multiple factors, including the host's immunological response. T lymphocytes, specifically CD4+ T helper cells and CD8+ cytotoxic T cells, are crucial in controlling parasite growth and activating cells for parasite clearance via cytokine secretion. Contrary to this, reports also suggest the pathogenic nature of T lymphocytes as they are often involved in disease progression and severity. CD8+ cytotoxic T cells migrate to the host's brain vasculature, disrupting the blood-brain barrier and causing neurological manifestations. CD4+ T helper cells on the other hand play a variety of functions as they differentiate into different subtypes which may function as pro-inflammatory or anti-inflammatory. The excessive pro-inflammatory response in CM can lead to multi-organ failure, necessitating a check mechanism to maintain immune homeostasis. This is achieved by regulatory T cells and their characteristic cytokines, which counterbalance the pro-inflammatory immune response. Maintaining a critical balance between pro and anti-inflammatory responses is crucial for determining disease outcomes in CM. A slight change in this balance may contribute to a disease severity owing to an extreme inflammatory response or unrestricted parasite growth, a potential target for designing immunotherapeutic treatment approaches. The review briefly discusses the pathogenesis of CM and various mechanisms responsible for the disruption of the blood-brain barrier. It also highlights the role of different T cell subsets during infection and emphasizes the importance of balance between pro and anti-inflammatory T cells that ultimately decides the outcome of the disease.

High-fat diet-induced obesity causes intestinal Th17/Treg imbalance that impairs the intestinal barrier and aggravates anxiety-like behavior in mice

The prevalence of autism spectrum disorders (ASD) has been steadily increasing, and growing evidence suggests a link between high-fat diet (HFD), obesity, and ASD; however, the mechanism underlying this association remains elusive. Herein, BTBR T + tf/J (BTBR) inbred mice (a mouse ASD model) and C57Bl/6J (C57) mice were fed an HFD and normal diet (ND) for 8 weeks (groups: C57 + ND, C57 + HFD, BTBR + ND, and BTBR + HFD). Subsequently, mice underwent behavioral assessments, followed by intestinal tissues harvesting to detect expression of intestinal barrier proteins and inflammatory factors and immune cell numbers, and a correlation analysis. HFD-fed BTBR mice developed obesity, elevated blood sugar, significantly aggravated anxiety-like behaviors, impaired intestinal barrier function, intestinal inflammation with elevated CD4+IL17+ T (Th17) cells and reduced CD4+Foxp3+ T (Treg) cells, exhibiting reduced expression of proteins related to AMPK regulatory pathway (AMPK, p-AMPK, SIRT1). Correlation analysis revealed that the degree of behavioral anxiety, the degree of intestinal barrier damage, the severity of intestinal inflammation, and the degree of immune cell imbalance positively correlated with each other. Accordingly, HFD-induced obesity may cause intestinal Th17/Treg imbalance via the AMPK-SIRT1 pathway, leading to an inflammatory environment in the intestine, impairing intestinal barrier function, and ultimately aggravating anxiety-like behaviors in mice.

Extracorporeal photopheresis reduces inflammation and joint damage in a rheumatoid arthritis murine model

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammatory reactions and tissue damage in the joints. Long-term drug use in clinical practice is often accompanied by adverse reactions. Extracorporeal photopheresis (ECP) is an immunomodulatory therapy with few side effects, offering a potential and safe therapeutic alternative for RA through the induction of immune tolerance. This study aimed to investigate the therapeutic effects of ECP on RA using a collagen-induced arthritis (CIA) murine model, as well as to explore its immunomodulatory effects in vivo. Additionally, particular attention was given to the significant role of monocytes during the ECP process.

METHODS

A murine model of rheumatoid arthritis was established by administering two injections of bovine type II collagen to DBA/1J mice. ECP, ECP-MD (mononuclear cells were depleted during the ECP), MTX, and PBS treatment were applied to the CIA mice. During the treatment process, clinical scores and body weight changes of CIA mice were closely monitored. After six treatment sessions, micro-CT images of the hind paws from live mice were captured. Ankle joints and paws of the mice were collected and processed for histological evaluation. Spleen samples were collected to measure the Th17/Treg cells ratio, and serum samples were collected to assess cytokine and anti-type II collagen IgG levels. Monocytes and dendritic cells populations before and after ECP in vitro were detected by flow cytometry.

RESULT

ECP therapy significantly attenuated the progression of CIA, alleviated the severity of clinical symptoms in CIA mice and effectively suppressed synovial hyperplasia, inflammation, and cartilage damage. There was an expansion in the percentage of CD3 + CD4 + CD25 + FoxP3 + Tregs and a decrease in CD3 + CD4 + IL17A + Th17 cells in vivo. Furthermore, ECP reduced the serum levels of pro-inflammatory cytokines IL-6 (53.47 ± 7.074 pg/mL vs 5.142 ± 1.779 pg/mL, P < 0.05) and IL-17A (3.077 ± 0.401 pg/mL vs 0.238 ± 0.082 pg/mlL, P < 0.0001) compared with PBS. Interestingly, the depletion of monocytes during the ECP process did not lead to any improvement in clinical symptoms or histological scores in CIA mice. Moreover, the imbalance in the Th17/Treg cells ratio became even more pronounced, accompanied by an augmented secretion of pro-inflammatory cytokines IL-6 and IL-17A. In vitro, compared with cells without ECP treatment, the proportion of CD11b + cells were significantly reduced (P < 0.01), the proportion of CD11c + cells were significantly elevated (P < 0.001) 24 h after ECP treatment. Additionally, the expression of MHC II (P < 0.0001), CD80 (P < 0.01), and CD86 (P < 0.001) was downregulated in CD11c + cells 24 h after ECP treatment.

CONCLUSION

Our study demonstrates that ECP exhibits a therapeutic effect comparable to conventional therapy in CIA mice, and the protective mechanisms of ECP against RA involve Th17/Treg cells ratio, which result in decreased IL-6 and IL-17A. Notably, monocytes derived from CIA mice are an indispensable part to the efficacy of ECP treatment, and the proportion of monocytes decreased and the proportion of tolerogenic dendritic cells increased after ECP treatment in vitro.

Imbalance of TH17/TREG cells in Tunisian patients with systemic sclerosis

Fibrosis is a pathological manifestation in which connective tissue replaces normal one. It can affect many tissues from the skin to internal organs such as the lungs. Manifestations of pulmonary involvement can be pulmonary arterial hypertension or pulmonary fibrosis. The latter one is currently the leading cause of death in various autoimmune diseases, including systemic sclerosis. Our study group consists of 50 patients with systemic sclerosis: 24 with limited cutaneous form and 26 with diffuse cutaneous form. This cohort was compared to 50 healthy controls (age and sex matched); our aim is to explore the distribution of TH17 cells (TH17) as well as regulatory T cells (TREG) and study their correlation with the disease's progress. Our results show an increase for IL17A in patients compared to controls and that this increase is correlated with a specific clinical involvement: Pulmonary fibrosis. This correlation suggests a crucial role of IL17A in fibrosis especially in systemic sclerosis. In addition, we have shown that the percentages of TH17 cells are higher in patients; however, the percentages of TREG cells are similar between patients and controls. A study of TREG cell activity showed that TREG lost suppressive activity by inactivating the FOXP3 transcription factor. This proves that despite their presence, TREG does not adequately carry out their regulatory activity. Finally, we analyzed the correlation between TH17/TREG and clinical damage; the results show a positive correlation with pulmonary involvement proving the role of TH17/TREG balance in induced fibrosis in systemic sclerosis. No significative difference was observed, for all the parameters, between the two different forms of the disease. In conclusion, the results associated with the TH17/TREG scale and their correlations with fibrosis in systemic sclerosis open a way for new tools to manage this autoimmune disease, which up to today has neither treatment nor accurate diagnosis.

Add-on sirolimus for the treatment of mild or moderate systemic lupus erythematosus via T lymphocyte subsets balance

OBJECTIVE

The efficacy of sirolimus in treating severe or refractory systemic lupus erythematosus (SLE) has been confirmed by small-scale clinical trials. However, few studies focused on mild or moderate SLE. Therefore, in this study we elucidated clinical efficacy of add-on sirolimus in patients with mild or moderate SLE.

METHODS

Data of 17 consecutive patients with SLE were retrospectively collected. SLE Disease Activity Index-2000 (SLEDAI-2K), clinical manifestation, laboratory data and peripheral T lymphocyte subsets with cytokines were collected before and 6 months after sirolimus add-on treatment. T cell subsets were detected by flow cytometry and cytokines were determined by multiplex bead-based flow fluorescent immunoassay simultaneously. Twenty healthy controls matched with age and sex were also included in our study.

RESULTS

(1) The numbers of peripheral blood lymphocytes, T cells, T helper (Th) cells, regulatory T (Treg) cells, Th1 cells, Th2 cells and Treg/Th17 ratios in patients with SLE were significantly lower, while the numbers of Th17 cells were evidently higher than those of healthy control (p<0.05). (2) After 6 months of sirolimus add-on treatment, urinary protein, pancytopenia, immunological indicators and SLEDAI-2K in patients with SLE were distinctively improved compared with those before sirolimus treatment (p<0.05). (3) The numbers of peripheral blood lymphocytes, T cells, Th cells, Treg cells, Th2 cells and the ratios of Treg/Th17 in patients with SLE after treatment were clearly higher than those before (p<0.05). (4) The levels of plasma interleukin (IL)-5, IL-6 and IL-10 in patients with SLE decreased notably, conversely the IL-4 levels increased remarkably compared with pretreatment (p<0.05).

CONCLUSIONS

(1) Patients with SLE presented imbalanced T cell subsets, especially the decreased ratio of Treg/Th17. (2) Sirolimus add-on treatment ameliorated clinical involvement, serological abnormalities and disease activity without adverse reactions in patients with SLE. (3) The multi-target therapy facilitates the enhanced numbers of Treg cells, Treg/Th17 imbalance and anti-inflammatory cytokines, simultaneously, reducing inflammatory cytokines.

Efficacy, Safety and the Lymphocyte Subset Changes of Low-Dose IL-2 in Patients with Autoimmune Rheumatic Diseases: A Systematic Review and Meta-Analysis

INTRODUCTION

Current therapies for autoimmune rheumatic diseases (ARDs) have limited efficacy in certain patients, highlighting the need for the development of novel treatment approaches. This meta-analysis aims to assess the efficacy and safety of low-dose interleukin-2 (LD-IL-2) and evaluate the alterations in lymphocyte subsets in various rheumatic diseases following administration of different dosages of LD-IL-2.

METHODS

A comprehensive search was conducted in PubMed, Web of Science, the Cochrane Library, Embase databases and CNKI to identify relevant studies. A total of 31 trials were included in this meta-analysis. The review protocols were registered on PROSPERO (CRD42022318916), and the study followed the PRISMA guidelines.

RESULTS

Following LD-IL-2 treatment, patients with ARDs exhibited a significant increase in the number of Th17 cells and Tregs compared to their pre-treatment levels [standardized mean difference (SMD) = 0.50, 95% confidence interval (CI) (0.33, 0.67), P < 0.001; SMD = 1.13, 95% CI (0.97, 1.29), P < 0.001]. Moreover, the Th17/Tregs ratio showed a significant decrease [SMD = - 0.54, 95% CI (- 0.64, - 0.45), P < 0.001]. In patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), LD-IL-2 injection led to a significant increase in Treg numbers, and the Th17/Tregs ratio and disease activity scores, including Disease Activity Score-28 joints (DAS28), Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) and Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), were all significantly reduced. No serious adverse events were reported in any of the included studies. Additionally, 54.8% of patients with lupus nephritis achieved distinct clinical remission following LD-IL-2 treatment. Injection site reactions and fever were the most common side effects of LD-IL-2, occurring in 33.1% and 14.4% of patients, respectively.

CONCLUSION

LD-IL-2 treatment showed promise and was well tolerated in the management of ARDs, as it effectively promoted the proliferation and functional recovery of Tregs.

TRIAL REGISTRATION

Retrospectively registered (CRD42022318916, 21/04/2022).

α-mangostin derivatives ameliorated mouse DSS-induced chronic colitis via regulating Th17/Treg balance

Th17 cell, an important subpopulation of helper T cell, plays an important role in the development of inflammatory bowel disease (IBD) and is thought to be a potential target for the treatment of IBD. In our previous study, we demonstrated that α-mangostin could relieve lupus nephritis via inhibiting Th17 cell function. In our preliminary study, we obtained four derivatives by adding chemical modification of α-mangostin which could also inhibit Th17 cell differentiation in vitro. In this study, we constructed a chronic IBD mouse model and demonstrated the therapeutic effects of α-mangostin and its derivatives as therapeutic agents for IBD. In compounds treating groups, intestinal inflammation showed significant improvement in symptoms which included weight loss, high disease activity index, colon length shorten and the change of intestinal flora. We also found that compounds could effectively either suppress the number of Th17 cell or increase the number of Treg cell detected by flow cytometry, thus reducing the Th17/Treg ratio and suppressing the level of intestinal inflammation. Notably, IL17-F levels, rather than IL17-A, were reduced in the colon of mice of compounds treating groups. Thus, α-mangostin and its derivatives ameliorate DSS-induced chronic colitis in mice by regulating Th17/Treg balance to alleviate intestinal inflammation and can modulate the intestinal microbial community. These results suggest that α-mangostin and its derivatives may be the new therapeutic option for chronic colitis.

Engineering M2 type macrophage-derived exosomes for autoimmune hepatitis immunotherapy via loading siRIPK3

Autoimmune hepatitis (AIH) is a progressive liver disease mediated by the immune system that involves an imbalance in pro-inflammatory and regulatory mechanisms including regulatory T cells (Tregs), T helper 17 (Th17) cells, Th1, macrophages, and many other immune cells. Current steroid therapy for AIH has significant systemic side effects and is poorly tolerated by some individuals. Therefore, there is an urgent need for alternative treatments. Maintaining homeostasis in macrophage differentiation and activation is crucial for regulating immune responses in hepatitis. In this study, we loaded small interfering RNA (siRNA) targeting receptor-interacting protein kinase 3 (RIPK3) into M2-type macrophage-derived exosomes (M2 Exos) to create functionalized exosomes called M2 Exos/siRIPK3. These exosomes demonstrated a natural ability to target the liver in mice, as they were efficiently taken up by hepatic macrophages and showed significant and stable accumulation. M2 Exos/siRIPK3 effectively mitigated immune-mediated hepatitis by suppressing the expression of RIPK3, resulting in a reduced release of pro-inflammatory cytokines and chemokines in both liver tissues and serum. Additionally, M2 Exos/siRIPK3 exhibited immunomodulatory effects, as its administration resulted in a decreased proportion of hepatic and splenic Th17 cells, along with an increased ratio of Tregs. Overall, this study suggests that loading small molecule drugs onto M2 Exos could be a promising approach for developing immunomodulators that specifically target liver macrophages to treat AIH. This strategy has the potential to provide a safer and more effective alternative to current therapy for AIH patients.

Pro-inflammatory cells sustain leukemic clonal expansion in T-cell large granular lymphocyte leukemia

T-cell large granular lymphocyte leukemia (T-LGLL) is a chronic lymphoproliferative disorder characterized by the clonal expansion of T-cell large granular lymphocytes (T-LGL). Immunophenotypic and genotypic features contribute to discriminate symptomatic (CD8+ STAT3-mutated T-LGLL) from clinically indolent patients, this latter group including CD8+ wildtype (wt), CD4+ STAT5B-mutated and wt cases. T-LGL lymphoproliferation is sustained both by somatic gain-offunction mutations (i.e., STAT3 and STAT5B) and by pro-inflammatory cytokines, but little information is available on the activity of T-LGLL non-leukemic cells. In this study, we characterized pro-inflammatory cells in the peripheral blood of T-LGLL patients and analyzed their role in supporting the leukemic growth. In symptomatic patients we found that cell populations not belonging to the leukemic component showed a discrete pro-inflammatory pattern. In particular, CD8+ STAT3-mutated cases showed a skewed Th17/Treg ratio and an abnormal distribution of monocyte populations characterized by increased intermediate and non-classical monocytes. We also demonstrated that monocytes released high levels of interleukin-6 after CCL5 stimulation, a chemokine specifically expressed only by leukemic LGL. Conversely, in asymptomatic cases an altered distribution of monocyte populations was not detected. Moreover, T-LGLL patients' monocytes showed abnormal activation of signaling pathways, further supporting the different pathogenic role of monocytes in patients in discrete clinical settings. Altogether, our data contribute to deepening the knowledge on the different cell subtypes in T-LGLL, focusing particularly on non-leukemic cell populations and thus offering the rationale for new therapeutic strategies.

A new generation of mesenchymal stromal/stem cells differentially trained by immunoregulatory probiotics in a lupus microenvironment

BACKGROUND

Increasing evidence suggests that multipotent mesenchymal stem/stromal cells (MSCs) are a promising intervention strategy in treating autoimmune inflammatory diseases. It should be stated that systemic immunoregulation is increasingly recognized among the beneficial effects of MSCs and probiotics in treating morbid autoimmune disorders such as lupus. This study aimed to determine if immunoregulatory probiotics L. rhamnosus or L. delbrueckii can change the immunomodulatory effects of MSCs in lupus-like disease.

METHODS

Pristane-induced lupus (PIL) mice model was created via intraperitoneal injection of Pristane and then confirmed. Naïve MSCs (N-MSCs) were coincubated with two Lactobacillus strains, rhamnosus (R-MSCs) or delbrueckii (D-MSCs), and/or a combination of both (DR-MSCs) for 48 h, then administrated intravenously in separate groups. Negative (PBS-treated normal mice) and positive control groups (PBS-treated lupus mice) were also investigated. At the end of the study, flow cytometry and enzyme-linked immunosorbent assay (ELISA) analysis were used to determine the percentage of Th cell subpopulations in splenocytes and the level of their master cytokines in sera, respectively. Moreover, lupus nephritis was investigated and compared. Analysis of variance (ANOVA) was used for multiple comparisons.

RESULTS

Abnormalities in serum levels of anti-dsDNA antibodies, creatinine, and urine proteinuria were significantly suppressed by MSCs transplantation, whereas engrafted MSCs coincubation with both L. strains did a lesser effect on anti-dsDNA antibodies. L. rhamnosus significantly escalated the ability of MSCs to scale down the inflammatory cytokines (IFN-ɣ, IL-17), while L. delbrueckii significantly elevated the capacity of MSCs to scale down the percentage of Th cell subpopulations. However, incubation with both strains induced MSCs with augmented capacity in introducing inflammatory cytokines (IFN-ɣ, IL-17). Strikingly, R-MSCs directly restored the serum level of TGF-β more effectively and showed more significant improvement in disease parameters than N-MSCs. These results suggest that R-MSCs significantly attenuate lupus disease by further skew the immune phenotype of MSCs toward increased immunoregulation.

CONCLUSIONS

Results demonstrated that Lactobacillus strains showed different capabilities in training/inducing new abilities in MSCs, in such a way that pretreated MSCs with L. rhamnosus might benefit the treatment of lupus-like symptoms, given their desirable properties.

The foreign body response: emerging cell types and considerations for targeted therapeutics

The foreign body response (FBR) remains a clinical challenge in the field of biomaterials due to its ability to elicit a chronic and sustained immune response. Modulating the immune response to materials is a modern paradigm in tissue engineering to enhance repair while limiting fibrous encapsulation and implant isolation. Though the classical mediators of the FBR are well-characterized, recent studies highlight that our understanding of the cell types that shape the FBR may be incomplete. In this review, we discuss the emerging role of T cells, stromal-immune cell interactions, and senescent cells in the biomaterial response, particularly to synthetic materials. We emphasize future studies that will deepen the field's understanding of these cell types in the FBR, with the goal of identifying therapeutic targets that will improve implant integration. Finally, we briefly review several considerations that may influence our understanding of the FBR in humans, including rodent models, aging, gut microbiota, and sex differences. A better understanding of the heterogeneous host cell response during the FBR can enable the design and development of immunomodulatory materials that favor healing.

Long noncoding RNA MEG8 induces an imbalance of Th17/Treg cells through the miR-107/STAT3 axis in Henoch-Schonlein purpura rats

T-helper (Th) 17/ T-regulatory (Treg) cell dysregulation underlies the pathogenesis of Henoch-Schonlein purpura (HSP). This research focused on the implication/s of the long noncoding RNA (lncRNAs) maternally expressed gene 8 (MEG8) in Th17 and Treg cell differentiation in HSP rats. MEG8, miR-107, signal transducer and activator of transcription-3 (STAT3), receptor-related orphan receptor γt (RORγt), and the transcription factor forkhead box P3 (Foxp3) expression levels were detected using real-time quantitative polymerase chain reaction and Western blot analyses. Flow cytometry was employed for measuring Th17 and Treg cells within the CD4+ T cell population. The interaction between miR-107 and MEG8 or STAT3 was examined. A low proportion of MEG8 and Treg cells together with Th17 cells were denoted within HSP rats. Moreover, MEG8 overexpression altered the Th17/Treg imbalance in peripheral blood CD4+ T-cell population, and the miR-107 mimic and STAT3 silencing reversed this effect. Thus, MEG8 served as a sponge for miR-107, lowering binding activity to STAT3 and thus overexpressing the molecule. Taken together, MEG8 induces an imbalance of Th17/Treg cells through the miR-107/STAT3 axis in HSP rats.

Disrupted Neural Regeneration in Dry Eye Secondary to Ankylosing Spondylitis-With a Theoretical Link between Piezo2 Channelopathy and Gateway Reflex, WDR Neurons, and Flare-Ups

This study aimed at analyzing the corneal neural regeneration in ankylosing spondylitis patients using in vivo corneal confocal microscopy in correlation with Langerhans cell density, morphology, and dry eye parameters. Approximately 24 ankylosing spondylitis subjects and 35 age- and gender-matched control subjects were enrolled. Data analysis showed that all corneal nerve-fiber descriptives were lower in the ankylosing spondylitis group, implicating disrupted neural regeneration. Peripheral Langerhans cell density showed a negative correlation with nerve fiber descriptions. A negative correlation between tear film break-up time and corneal nerve fiber total branch density was detected. The potential role of somatosensory terminal Piezo2 channelopathy in the pathogenesis of dry eye disease and ankylosing spondylitis is highlighted in our study, exposing the neuroimmunological link between these diseases. We hypothesized earlier that spinal neuroimmune-induced sensitization due to this somatosensory terminal primary damage could lead to Langerhans cell activation in the cornea, in association with downregulated Piezo1 channels on these cells. This activation could lead to a Th17/Treg imbalance in dry eye secondary to ankylosing spondylitis. Hence, the corneal Piezo2 channelopathy-induced impaired Piezo2-Piezo1 crosstalk could explain the disrupted neural regeneration. Moreover, the translation of our findings highlights the link between Piezo2 channelopathy-induced gateway to pathophysiology and the gateway reflex, not to mention the potential role of spinal wide dynamic range neurons in the evolution of neuropathic pain and the flare-ups in ankylosing spondylitis and dry eye disease.

Impaired immunosuppressive effect of bone marrow mesenchymal stem cell-derived exosomes on T cells in aplastic anemia

BACKGROUND

Previous studies have verified the dysfunction of mesenchymal stem cells (MSCs) for immunoregulation in acquired aplastic anemia (AA) patients. Exosomes derived from MSCs can partially substitute MSCs acting as immune regulator. Dysfunction of exosomes (Exos) derived from AA-MSC (AA-Exos) may play a key role in immunologic dissonance.

METHOD

In this study, CD3 + T cells were collected and cocultured with AA-Exos and exosomes derived from HD-MSC (HD-Exos). The proliferation, differentiation and activation of CD3 + T cells were detected to compare the immunosuppressive effects between AA-Exos and HD-Exos. An immune-mediated murine model of AA was structured to compare the therapeutic effect of AA-Exos and HD-Exos. Furthermore, total RNA including miRNA from exosomes we purified and total RNA of CD3 + T cells were extracted for RNA-seq in order to construct the miRNA-mRNA network for interactions and functional analysis.

RESULTS

AA-Exos had impaired inhibition effects on CD3 + T cells in terms of cell proliferation, activation and differentiation compared with exosomes from HD-Exos. HD-Exos showed a more effective rescue of AA mice compared to AA-Exos. Importantly, we found some differentially expressed miRNA involved in immune response, such as miR-199, miR-128 and miR-486. The Gene Ontology analysis of differentially expressed genes (DEGs) revealed involvement of various cellular processes, such as lymphocyte chemotaxis, lymphocyte migration and response to interferon-gamma. The Kyoto Encyclopedia of Genes and Genomes analysis illustrated upregulation of critical pathways associated with T cell function after coculturing with AA-Exos compared with HD-Exos, such as graft-versus-host disease, Th17 cell differentiation and JAK-STAT signaling pathway. A miRNA-mRNA network was established to visualize the interaction between them.

CONCLUSION

In summary, AA-Exos had impaired immunosuppressive effect on T cells, less ability to rescue AA mice and differently expressed miRNA profile, which might partly account for the pathogenesis of AA as well as provide a new target of AA treatment.

Discovery of a Bromodomain and Extra Terminal Domain (BET) Inhibitor with the Selectivity for the Second Bromodomain (BD2) and the Capacity for the Treatment of Inflammatory Diseases

Selective inhibitors targeting the first bromodomain (BD1) or the second bromodomain (BD2) of the bromodomain and extra terminal domain (BET) proteins have triggered extensive research to produce more specific agents. Herein, we described our efforts to design and synthesize a series of selective BET BD2 inhibitors with novel structures. Among them, compound 45 showed single-digit nanomolar potency against BRD4 BD2 (IC50: 1.6 nM) and a 328-fold selectivity for BRD4 BD2 over BRD4 BD1 (IC50: 524 nM). Besides, 45 possessed potent effects on regulating the differentiation of Th17 cells and reducing the levels of Th17-related cytokines by affecting the activation of STAT3 and NF-κB. Further studies demonstrated that 45 had significant therapeutic efficacy in mouse models of imiquimod (IMQ)-induced psoriasis and dextran sulfate sodium (DSS)-induced inflammatory bowel disease (IBD). This work provides a strong foundation for the development of selective BET BD2 inhibitors and the therapeutic strategy for psoriasis and IBD.

Reactive oxygen species formation and its effect on CD4+ T cell-mediated inflammation

Reactive oxygen species (ROS) are produced both enzymatically and non-enzymatically in vivo. Physiological concentrations of ROS act as signaling molecules that participate in various physiological and pathophysiological activities and play an important role in basic metabolic functions. Diseases related to metabolic disorders may be affected by changes in redox balance. This review details the common generation pathways of intracellular ROS and discusses the damage to physiological functions when the ROS concentration is too high to reach an oxidative stress state. We also summarize the main features and energy metabolism of CD4+ T-cell activation and differentiation and the effects of ROS produced during the oxidative metabolism of CD4+ T cells. Because the current treatment for autoimmune diseases damages other immune responses and functional cells in the body, inhibiting the activation and differentiation of autoreactive T cells by targeting oxidative metabolism or ROS production without damaging systemic immune function is a promising treatment option. Therefore, exploring the relationship between T-cell energy metabolism and ROS and the T-cell differentiation process provides theoretical support for discovering effective treatments for T cell-mediated autoimmune diseases.

Autoimmunity: A New Focus on Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) has long been considered a benign, chronic inflammatory, and hyperplastic disease. Recent studies have shown that autoimmune-related mechanisms are involved in the pathology of nasal polyps. Activated plasma cells, eosinophils, basophils, innate type 2 lymphocytes, mast cells, and proinflammatory cytokine in polyp tissue indicate the mobilization of innate and adaptive immune pathways during polyp formation. The discovery of a series of autoantibodies further supports the autoimmune nature of nasal polyps. Local homeostasis dysregulation, infection, and chronic inflammation may trigger autoimmunity through several mechanisms, including autoantigens overproduction, microbial translocation, molecular mimicry, superantigens, activation or inhibition of receptors, bystander activation, dysregulation of Toll-Like Receptors (TLRs), epitope spreading, autoantigens complementarity. In this paper, we elaborated on the microbiome-mediated mechanism, abnormal host immunity, and genetic changes to update the role of autoimmunity in the pathogenesis of chronic rhinosinusitis with nasal polyps.

Androgen-Induced Cardiovascular Risk in Polycystic Ovary Syndrome: The Role of T Lymphocytes

An estimated 15-20% of reproductive-age women are affected by polycystic ovary syndrome (PCOS). PCOS is associated with substantial metabolic and cardiovascular long-term consequences. In young women with PCOS, several cardiovascular risk factors may be found, including chronic inflammation, high blood pressure, and elevated leukocytes. These women are at an increased risk of cardiovascular diseases (CVD), not only during the reproductive years, but also with aging and menopause; therefore, the early prevention and treatment of future cardiovascular adverse effects are necessary. The fundamental characteristic of PCOS is hyperandrogenemia, which is associated with increased pro-inflammatory cytokines and T lymphocytes. Whether these factors play a role in the pathophysiology of hypertension, a risk factor of CVD, due to PCOS is not well established. This review will briefly discuss how a modest increase in androgens in females is linked to the development of hypertension through pro-inflammatory cytokines and T lymphocyte subsets and the promotion of renal injury. Moreover, it reveals a few existing research gaps in this area, including the lack of specific therapy directed at androgen-induced inflammation and immune activation, thus emphasizing the necessity to explore the systemic inflammation in women with PCOS to halt the inevitable inflammatory process targeting the underlying abnormalities of CVD.

Phosphatase Ssu72 Is Essential for Homeostatic Balance Between CD4+ T Cell Lineages

Ssu72, a dual-specificity protein phosphatase, not only participates in transcription biogenesis, but also affects pathophysiological functions in a tissue-specific manner. Recently, it has been shown that Ssu72 is required for T cell differentiation and function by controlling multiple immune receptor-mediated signals, including TCR and several cytokine receptor signaling pathways. Ssu72 deficiency in T cells is associated with impaired fine-tuning of receptor-mediated signaling and a defect in CD4+ T cell homeostasis, resulting in immune-mediated diseases. However, the mechanism by which Ssu72 in T cells integrates the pathophysiology of multiple immune-mediated diseases is still poorly elucidated. In this review, we will focus on the immunoregulatory mechanism of Ssu72 phosphatase in CD4+ T cell differentiation, activation, and phenotypic function. We will also discuss the current understanding of the correlation between Ssu72 in T cells and pathological functions which suggests that Ssu72 might be a therapeutic target in autoimmune disorders and other diseases.

Cornus mas L. Extract Targets the Specific Molecules of the Th17/Treg Developmental Pathway in TNBS-Induced Experimental Colitis in Rats

Given that one of the crucial events in the pathogenesis of inflammatory bowel disease is the loss of homeostasis between Th17 and Treg cells, targeting the specific molecules of the Th17/Treg axis developmental pathway is a promising strategy for inflammatory bowel disease prevention and treatment. The current study aimed to assess the impact of cornelian cherry (Cornus mas L.) extract, rich in iridoids and polyphenols known for their potential anti-inflammatory activity, at two doses (20 or 100 mg/kg) on the crucial factors for Th17/Treg cell differentiation in the course of experimental colitis and compare this action with that of sulfasalazine. This study was conducted on the biobank colon tissue samples collected during the previous original experiment, in which colitis in rats was induced by trinitrobenzenesulfonic acid (TNBS). The levels of IL-6, RORγt, total STAT3, p-STAT3, and Foxp3 were determined by ELISA. The expression of PIAS3 mRNA was quantified by qPCR. Cornelian cherry extract at a dose of 100 mg/kg counteracted the TNBS-induced elevation of IL-6, RORγt, and p-STAT3 levels and a decrease in Foxp3 level and PIAS3 mRNA expression, while given concomitantly with sulfasalazine was more effective than sulfasalazine alone in reversing the TNBS-induced changes in IL-6, RORγt, total STAT3, p-STAT3, Foxp3 levels, and PIAS3 mRNA expression. The beneficial effect of cornelian cherry extract on experimental colitis may be due to its immunomodulatory activity reflected by the influence on factors regulating the Th17/Treg axis.

A postulated model for photoimmunopathogenesis of chronic actinic dermatitis around adaptive immunity, including Th17 cells, Tregs, TRMs, cytotoxic T cells, and/or common-γ chain receptor+ cells

BACKGROUND/PURPOSE

The pathogenesis of chronic actinic dermatitis (CAD) is more complicated than other photodermatoses. However, the relationship between the clinical severity of CAD and the offending photocontact or contact allergens or both, and the correlations of CAD immunopathogenesis with the immunoregulatory molecules involved in adaptive immunity are yet to be investigated.

METHODS

We performed phototesting with broad-spectrum ultraviolet (UV) B, UVA, and visible light to establish the presence of photosensitivity in 121 patients with CAD, together with photopatch and contact patch testing. Nine patients with CAD were selected according to their clinical severity score for CAD (CSS-CAD), and triple direct immunofluorescence analysis was performed with paraffin-embedded skin biopsy samples.

RESULTS

As CSS-CAD was closely correlated with the multiplicity of photo(contact) allergens, particularly photoallergens, three or more photoallergens were detected in the severe CAD group (52.5%); less in the moderate group (32.8%); and only one in the mild group (14.8%; P = .025). In the groups showing greater severity of disease, the absolute numbers of IFN-γ⁺ , IL-17⁺ , CD4+, CD8+, common-γ chain receptor (common-γCR)⁺ , and CD69⁺ tissue-resident memory cells increased on average; there was also an increase in the CD4+/CD8+ cell ratio, with the more severely affected groups. However, the levels of TNF-α⁺ and FoxP3⁺ regulatory T (Treg) cells and the mean IL-17/IFN-γ cell ratio decreased in the more severely affected CSS-CAD subgroups.

CONCLUSIONS

Based on the clinical analysis and immunopathogenic results, avoidance of excessive sun exposure, and topical and systemic blocking agents for photo(contact) allergens are recommended. Additionally, conventional immunomodulators and emerging agents including JAK-STAT inhibitors may be administered for CAD treatment in the future.

Dysregulated balance in Th17/Treg axis of Pristane-induced lupus mouse model, are mesenchymal stem cells therapeutic?

BACKGROUND

Despite advances in general and targeted immunosuppressive therapies, limiting all mainstay treatment options in refractory systemic lupus erythematosus (SLE) cases has necessitated the development of new therapeutic strategies. Mesenchymal stem cells (MSCs) have recently emerged with unique properties, including a solid propensity to reduce inflammation, exert immunomodulatory effects, and repair injured tissues.

METHODS

An animal model of acquired SLE mice was induced via intraperitoneal immunization with Pristane and affirmed by measuring specific biomarkers. Bone marrow (BM) MSCs were isolated from healthy BALB/c mice and cultured in vitro, then were identified and confirmed by flow cytometry and cytodifferentiation. Systemic MSCs transplantation was performed and then several parameters were analyzed and compared, including specific cytokines (IL-17, IL-4, IFN-ɣ, TGF-β) at the serum level, the percentage of Th cell subsets (Treg/Th17, Th1/Th2) in splenocytes, and also the relief of lupus nephritis, respectively by enzyme-linked immunosorbent assay (ELISA), flow cytometry analysis and by hematoxylin & eosin staining and also immunofluorescence assessment. Experiments were carried out with different initiation treatment time points (early and late stages of disease). Analysis of variance (ANOVA) followed by post hoc Tukey's test was used for multiple comparisons.

RESULTS

The rate of proteinuria, anti-double-stranded deoxyribonucleic acid (anti-dsDNA) antibodies, and serum creatinine levels decreased with BM-MSCs transplantation. These results were associated with attenuated lupus renal pathology in terms of reducing IgG and C3 deposition and lymphocyte infiltration. Our findings suggested that TGF-β (associated with lupus microenvironment) can contribute to MSC-based immunotherapy by modulating the population of TCD4⁺ cell subsets. Obtained results indicated that MSCs-based cytotherapy could negatively affect the progression of induced SLE by recovering the function of Treg cells, suppressing Th1, Th2, and Th17 lymphocyte function, and downregulating their pro-inflammatory cytokines.

CONCLUSION

MSC-based immunotherapy showed a delayed effect on the progression of acquired SLE in a lupus microenvironment-dependent manner. Allogenic MSCs transplantation revealed the ability to re-establish the balance of Th17/Treg, Th1/Th2 and restore the plasma cytokines network in a pattern dependent on disease conditions. The conflicting results of early versus advanced therapy suggest that MSCs may produce different effects depending on when they are administered and their activation status.

Gallic acid regulates immune response in a mouse model of rheumatoid arthritis

INTRODUCTION

Previous studies revealed that gallic acid (GA) exerts anti-inflammation and immuno-regulatory properties. This study aims to explore the pharmacological activities of GA in collagen-induced arthritis (CIA) mouse model.

METHODS

Male DBA/1J mice were used to construct the CIA model. The mice were administrated with GA for 3 weeks. Clinical arthritis scores and hind paw volume were evaluated over the experimental period. qPCR and Western blot analysis were used to determine the levels of matrix metallopeptidases (MMPs) and cytokines. In addition, flow cytometry was used to measure the populations of Th17 and Treg cells. ELISAs were used to determine the cytokines in the serum and ankle joint tissues.

RESULTS

Treatment of GA (40 and 80 mg/kg/d) reduced clinical arthritis scores and hind paw volume in the CIA mouse model. Besides, treatment of GA reduced the overexpression of MMPs and modulated the dysregulation of inflammation-related cytokines. Flow cytometry showed that treatment of GA decreased the population of Th17 cells, and increased the population of Treg cells, as supported by treatment of GA regulated the Th17/Treg-related cytokines.

CONCLUSIONS

GA attenuates symptoms in the CIA mouse model by anti-inflammation and regulating Th17/Treg cell imbalance.

Relationship between Hypoxic and Immune Pathways Activation in the Progression of Neuroinflammation: Role of HIF-1α and Th17 Cells

Neuroinflammation is a common event in degenerative diseases of the central and peripheral nervous system, triggered by alterations in the immune system or inflammatory cascade. The pathophysiology of these disorders is multifactorial, whereby the therapy available has low clinical efficacy. This review propounds the relationship between the deregulation of T helper cells and hypoxia, mainly Th17 and HIF-1α molecular pathways, events that are involved in the occurrence of the neuroinflammation. The clinical expression of neuroinflammation is included in prevalent pathologies such as multiple sclerosis, Guillain-Barré syndrome, and Alzheimer's disease, among others. In addition, therapeutic targets are analyzed in relation to the pathways that induced neuroinflammation.

Pathogenesis and treatment of Sjogren's syndrome: Review and update

Sjogren's syndrome (SS) is a chronic autoimmune disease accompanied by multiple lesions. The main manifestations include dryness of the mouth and eyes, along with systemic complications (e.g., pulmonary disease, kidney injury, and lymphoma). In this review, we highlight that IFNs, Th17 cell-related cytokines (IL-17 and IL-23), and B cell-related cytokines (TNF and BAFF) are crucial for the pathogenesis of SS. We also summarize the advances in experimental treatment strategies, including targeting Treg/Th17, mesenchymal stem cell treatment, targeting BAFF, inhibiting JAK pathway, et al. Similar to that of SLE, RA, and MS, biotherapeutic strategies of SS consist of neutralizing antibodies and inflammation-related receptor blockers targeting proinflammatory signaling pathways. However, clinical research on SS therapy is comparatively rare. Moreover, the differences in the curative effects of immunotherapies among SS and other autoimmune diseases are not fully understood. We emphasize that targeted drugs, low-side-effect drugs, and combination therapies should be the focus of future research.

Probiotic consumption can modify the resilience of periodontal tissues in rats under experimental periodontitis

BACKGROUND

This study evaluated the effects of systemic administration of Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) on experimental periodontitis (EP) in rats.

METHODS

Thirty-two rats were allocated to groups C (control), C-HN019 (probiotic), EP (EP only), and EP-HN019 (EP+probiotic). From day 0, the animals of C-HN019 and EP-HN019 groups received B. lactis HN019 (1 × 10⁹ CFU/ml) daily. On the 14th day, the animals of EP and EP-HN019 groups received silk ligature around mandibular molars. Animals were euthanized on the 28th day. Samples of oral biofilm, gingival tissues, blood serum, and mandible were obtained for microtomographic, histomorphometric, microbiological, and immunological analyses. Data were statistically analyzed (p < 0.05).

RESULTS

Group EP-HN019 presented significantly less alveolar bone loss when compared with Group EP in histomorphometric and microtomographic analyses. In gingival tissue and serum, Group EP-HN019 presented lower proinflammatory/anti-inflammatory cytokines ratios than Group EP. Group EP-HN019 showed higher expression of beta-defensins and less TRAP-positive cells than Group EP. Group EP presented higher gene expression of Ifng and lower gene expression of Foxp3 when compared with Group EP-HN019 in gingival tissue. In oral biofilm, EP-HN019 group presented a lower percentage of species similar to Fusobacterium periodonticum and a higher percentage of species similar to Actinomyces gereneseriae, Actinomyces israelli, and Streptococcus gordonii when compared with Group EP. There was a significant increase of B. lactis HN019 after administration of probiotic therapy in oral biofilm of Group EP-HN019.

CONCLUSION

The consumption of B. lactis HN019 promotes a protective effect against alveolar bone loss by modifying local and systemic microbiological and immunoinflammatory parameters.

Acupuncture regulates the Th17/Treg balance and improves cognitive deficits in a rat model of vascular dementia

Objective

The present study was developed to explore the impact of acupuncture on the Th17/Treg balance in the brain and the periphery and associated changes in cognitive deficits in a rat model of vascular dementia (VD).

Methods

Male Wistar rats (8 weeks old) were randomly assigned to sham-operated (Gs, n = 10), and operation (n = 30) groups. A VD model was established for all rats in the operation group via the permanent bilateral occlusion of the common carotid artery. Behavioral screening of these rats was conducted via a hidden platform trial at 2 months post-operation. These operation group rats were then further subdivided into impaired (Gi) and acupuncture (Ga) groups (n = 10/group). Acupuncture was performed over a 21-day period for rats in the Ga group. A Morris water maze (MWM) test was used to assess cognitive function for rats in all groups. Flow cytometry and fluorescent staining were used to detect Th17 and Treg cells in samples from these animals based on IL-17/FoxP3 or CD4⁺FoxP3⁺/CD4⁺RORγt⁺ staining profiles.

Results

Relative to the Gs group, escape latency values for rats in the Gi group were significantly increased. Following treatment, rats in the Ga group exhibited significant reductions in escape latency values as compared to rats in the Gi group (P < 0.05). The relative Treg proportion in the peripheral blood and spleen additionally trended upwards in these Ga rats as compared to those in the Gi group (P > 0.05), whereas the frequency of Th17 cells in the peripheral blood and spleen of Ga group rats trended downward relative to the Gi group (P > 0.05). Significantly fewer CD4⁺RORγt⁺ and RORγt⁺ cells were detected in the Ga group relative to the Gi group, whereas CD4⁺FoxP3⁺ and FoxP3⁺ cell counts were increased (P < 0.01).

Conclusion

In summary, VD model rats exhibited dysregulated Th17/Treg homeostasis. Acupuncture treatment was sufficient to reduce the frequency and numbers of Th17 cells in these animals while increasing Treg cell levels, thereby alleviating cognitive deficits with respect to both spatial learning and memory impairment. Consequently, the therapeutic benefits of such acupuncture treatment may be attributable to the regulation of the Th17/Treg balance and associated improvements in cognitive function.

Berberine promotes immunological outcomes and decreases neuroinflammation in the experimental model of multiple sclerosis through the expansion of Treg and Th2 cells

INTRODUCTION

Among the most frequent demyelinating autoimmune disorders of the central nervous system (CNS) is multiple sclerosis. Experimental autoimmune encephalomyelitis (EAE) is used as an animal model of multiple sclerosis. Berberine is an alkaloid found in some medicinal plants with anti-inflammatory effects.

METHODS

C57BL/6 female mice were used and divided into three groups: (1) The control group received PBS, (2) the low-dose treatment group received 10 mg/kg of berberine, and (3) The high-dose treatment group received 30 mg/kg of berberine. Myelin Oligodendrocyte Glycoprotein and complete Freund's adjuvant were subcutaneously administered to induce EAE. Mice were given intraperitoneal injections of pertussis toxin on the day of immunization and 2 days later. Histological studies showed low lymphocyte infiltration and demyelination of CNS in the treated groups.

RESULTS

The clinical scores of the treatment group with low-dose berberine (T1: 2 ± 0.13) and high-dose berberine (T2: 1.5 ± 0.14) were significantly (p < .001) lower than the control group (CTRL: 4.5 ± 0.13). Treatment groups decreased pro-inflammatory cytokines (IFN-γ, TNF-α, interleukin [IL]-17) (p < .001) as well as increased anti-inflammatory cytokine expression (IL-4, IL-10, IL-27, IL-33, IL-35, TGF-β) (p < .01) when compared to the CTRL group. Treatment groups with berberine reduced expression of the Th1 and Th17 cytokines and transcription factors (p < .001) and increased expression of transcription factors and Th2 and Treg cytokines (p < .01) in contrast to CTRL group.

CONCLUSION

Berberine appears to have a protective effect on disease development and alleviating disease status in EAE, which appears to be due to the cell expansion and function of Treg and Th2 cells in addition to berberine's anti-inflammatory properties.

Breast cancer tumor microenvironment affects Treg/IL-17-producing Treg/Th17 cell axis: Molecular and therapeutic perspectives

The tumor microenvironment (TME) comprises a variety of immune cells, among which T cells exert a prominent axial role in tumor development or anti-tumor responses in patients with breast cancer (BC). High or low levels of anti-inflammatory cytokines, such as transforming growth factor β, in the absence or presence of proinflammatory cytokines, such as interleukin-6 (IL-6), delineate the fate of T cells toward either regulatory T (Treg) or T helper 17 (Th17) cells, respectively. The transitional state of RORγt⁺Foxp3⁺ Treg (IL-17-producing Treg) resides in the middle of this reciprocal polarization, which is known as Treg/IL-17-producing Treg/Th17 cell axis. TME secretome, including microRNAs, cytokines, and extracellular vesicles, can significantly affect this axis. Furthermore, immune checkpoint inhibitors may be used to reconstruct immune cells; however, some of these novel therapies may favor tumor development. Therefore, understanding secretory and cell-associated factors involved in their differentiation or polarization and functions may be targeted for BC management. This review discusses microRNAs, cytokines, and extracellular vesicles (as secretome), as well as transcription factors and immune checkpoints (as cell-associated factors), which influence the Treg/IL-17-producing Treg/Th17 cell axis in BC. Furthermore, approved or ongoing clinical trials related to the modulation of this axis in the TME of BC are described to broaden new horizons of promising therapeutic approaches.

MicroRNA-181a regulates Treg functions via TGF-β1/Smad axis in the spleen of mice with acute gouty arthritis induced by MSU crystals

Regulatory T cells (Tregs) play critical roles in restricting inflammatory pathogenesis and limiting undesirable Th2 response to environmental allergens. However, the role of miR-181a in regulating acute gouty arthritis (AGA) and Treg function remains unclear. This study aimed to investigate the potential roles of miR-181a in Treg immunity and the associated signaling pathway in the AGA mouse model. A solution with monosodium urate (MSU) crystals was injected into the joint tissue of mice to induce AGA. ELISA was used to examine inflammatory factors in blood samples, and flow cytometry was used to analyze Treg profile in mice with MSU-induced AGA. Cell proliferation and viability were assessed by CCK-8 assay. TGF-β1/Smad signaling activation was detected by western blot. We found that miR-181a expression showed a positive correlation with the changes of splenic Tregs percentage in AGA mice. miR-181a regulated the TGF-β1/Smad axis, since the transfection of miR-181a mimic increased the level of TGF-β1 and the phosphorylation of Smad2/3 in Tregs in AGA mice. Additionally, miR-181a mimic also promoted responses of Tregs via TGF-β1 in vitro and in vivo. Our work uncovered a vital role of miR-181a in the immune function of Treg cells by mediating the activity of the TGF-β1/Smad pathway in the AGA mouse model induced by MSU.

Qing-Chang-Hua-Shi granule ameliorates DSS-induced colitis by activating NLRP6 signaling and regulating Th17/Treg balance

BACKGROUND

Chinese herbal medicine Qing-Chang-Hua-Shi granule (QCHS) is widely used to treat ulcerative colitis in China. However, the molecular mechanisms of QCHS remains largely unknown.

PURPOSE

To assess the therapeutic effects of QCHS on colitis and to reveal its mechanisms of action.

METHODS

The main components of QCHS were identified using a UHPLC-QTOF-MS method and the efficacy of QCHS was evaluated using an DSS-induced mice model. The inflammatory responses and mucosal integrity in colon were comprehensively assessed. Flow cytometry was used to analysis the proportion of Th17 and Treg cells. Detect the signal transduction of the NOD-like receptor family pyrin domain containing 6 (NLRP6) both in vitro and in vivo. Furthermore, siNLRP6 transfection was used to validate the functional targets of QCHS.

RESULTS

QCHS treatment significantly alleviated colitis in mice by improving symptoms and pathological damage. Moreover, QCHS treatment suppressed the inflammatory response and preserved the integrity of colon tissue. Most importantly, QCHS balanced the Th17/Treg response of UC mice. Mechanistically, by activating NLRP6 inflammasome pathway, QCHS regulated the maturation of interleukin (IL)-1β and IL-18 to affect inflammation and drive Th17 cell differentiation.

CONCLUSIONS

The effect of QCHS on UC mice is dose-dependent, with high-dose QCHS being superior to 5-Aminosalicylic acid (200 mg/kg/day). QCHS acts through the NLRP6 signaling pathway to modulate Th17/Treg balance, resulting in the protective effects against colitis. This study investigated the relevant pharmacological mechanisms of QCHS, providing further evidence for the application of QCHS in UC treatment.

Polysaccharide from Atractylodes macrocephala Koidz. ameliorates DSS-induced colitis in mice by regulating the Th17/Treg cell balance

Atractylodes macrocephala Koidz. is one of the most frequently used traditional Chinese medicines for the treatment of ulcerative colitis (UC). The beneficial effect of polysaccharide from Atractylodes macrocephala Koidz. (PAMK) on UC has been reported, while the underlying mechanism and target remain unclear. In this study, we systematically investigated the therapeutic effect and the underlying mechanism of PAMK in UC based on a mouse model of dextran sodium sulfate (DSS)-induced colitis. PAMK treatment (100 mg/kg, 200 mg/kg and 400 mg/kg) significantly ameliorated DSS-induced colitis, manifested as a reduction in weight loss, disease activity index (DAI), colon shortening, spleen index and histological score. Moreover, PAMK treatment inhibited inflammation and improved the integrity of the intestinal barrier in colitis mice. Mechanistically, microarray analysis determined the critical role of the immunoregulatory effect of PAMK in alleviating UC. Flow cytometry analysis further demonstrated that PAMK treatment regulated the balance between T helper (Th) 17 and regulatory T (Treg) cells in the mesenteric lymph nodes (MLN) and spleen in mice with colitis. In addition, PAMK treatment downregulated the expression of IL-6 and suppressed the phosphorylation of STAT3. Together, these data revealed that PAMK treatment alleviated DSS-induced colitis by regulating the Th17/Treg cell balance, which may be dependent on the inhibition of the IL-6/STAT3 signaling pathway. Our study is the first to elucidate that the underlying mechanism by which PAMK treatment alleviates DSS-induced colitis is associated with an improved the Th17/Treg cell balance. Collectively, the study provides evidence for the potential of PAMK to treat UC.

The impact of herbal medicine in regulating intestinal flora on female reproductive disorders

As an important part of the human intestinal microecology, the intestinal flora is involved in a number of physiological functions of the host. Several studies have shown that imbalance of intestinal flora and its regulation of the intestinal barrier, intestinal immune response, and intestinal flora metabolites (short-chain fatty acids and bile acids) can affect the development and regression of female reproductive disorders. Herbal medicine has unique advantages in the treatment of female reproductive disorders such as polycystic ovary syndrome, endometriosis and premature ovarian insufficiency, although its mechanism of action is still unclear. Therefore, based on the role of intestinal flora in the occurrence and development of female reproduction-related diseases, the progress of research on the diversity, structure and composition of intestinal flora and its metabolites regulated by botanical drugs, Chinese herbal formulas and active ingredients of Chinese herbal medicines is reviewed, with a view to providing reference for the research on the mechanism of action of Chinese herbal medicines in the treatment of female reproductive disorders and further development of new herbal medicines.

Single-cell RNA sequencing analysis of T helper cell differentiation and heterogeneity

Single-cell transcriptomics has emerged as a powerful tool to investigate cells' biological landscape and focus on the expression profile of individual cells. Major advantage of this approach is an analysis of highly complex and heterogeneous cell populations, such as a specific subpopulation of T helper cells that are known to differentiate into distinct subpopulations. The need for distinguishing the specific expression profile is even more important considering the T cell plasticity. However, importantly, the universal pipelines for single-cell analysis are usually not sufficient for every cell type. Here, the aims are to analyze the diversity of T cell phenotypes employing classical in vitro cytokine-mediated differentiation of human T cells isolated from human peripheral blood by single-cell transcriptomic approach with support of labelled antibodies and a comprehensive bioinformatics analysis using combination of Seurat, Nebulosa, GGplot and others. The results showed high expression similarities between Th1 and Th17 phenotype and very distinct Th2 expression profile. In a case of Th2 highly specific marker genes SPINT2, TRIB3 and CST7 were expressed. Overall, our results demonstrate how donor difference, Th plasticity and cell cycle influence the expression profiles of distinct T cell populations. The results could help to better understand the importance of each step of the analysis when working with T cell single-cell data and observe the results in a more practical way by using our analyzed datasets.

B cell-T cell interplay in immune regulation: A focus on follicular regulatory T and regulatory B cell functions

B cells are the core components of humoral immunity. A mature B cell can serve in multiple capacities, including antibody production, antigen presentation, and regulatory functions. Forkhead box P3 (FoxP3)-expressing regulatory T cells (Tregs) are key players in sustaining immune tolerance and keeping inflammation in check. Mounting evidence suggests complex communications between B cells and Tregs. In this review, we summarize the yin-yang regulatory relationships between B cells and Tregs mainly from the perspectives of T follicular regulatory (Tfr) cells and regulatory B cells (Bregs). We discuss the regulatory effects of Tfr cells on B cell proliferation and the germinal center response. Additionally, we review the indispensable role of B cells in ensuring homeostatic Treg survival and describe the function of Bregs in promoting Treg responses. Finally, we introduce a new subset of Tregs, termed Treg-of-B cells, which are induced by B cells, lake the expression of FoxP3 but still own immunomodulatory effects. In this article, we also enumerate a sequence of research from clinical patients and experimental models to clarify the role of Tfr cells in germinal centers and the role of convention B cells and Bregs to Tregs in the context of different diseases. This review offers an updated overview of immunoregulatory networks and unveils potential targets for therapeutic interventions against cancer, autoimmune diseases and allograft rejection.

Traditional Chinese Medicine Regulates Th17/Treg Balance in Treating Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), also known as chronic nonspecific inflammatory disease of the colon and rectum, is primarily characterized by mucopurulent bloody stools, diarrhea, abdominal pain, and tenesmus. Its cause is uncertain. IBD patients frequently experience a high rate of recurrence, a protracted treatment course, and a high risk of carcinogenesis. Additionally, the difficulty of treatment is significantly increased by these illness characteristics. Currently, the normal treatment for this illness can lessen symptoms to some amount and even meet clinical treatment requirements, but due to serious side effects, unfavorable reactions, and high costs, we need to develop better complementary and alternative medicines. A number of studies have found that the imbalance of T helper cell 17 (Th17)/regulatory T cells (Treg) contributes significantly to the occurrence and progression of IBD and that Th17/Treg balance restoration is frequently useful in the management of IBD. As a result, regulating the Th17/Treg balance has also emerged as a novel approach to treating IBD. Traditional Chinese medicine (TCM) has gained popularity in recent years due to its advantages of low side effects, a variety of targets, and multiple regulatory mechanisms. A number of studies have shown that TCM can successfully intervene in the Th17/Treg imbalance and restore it, and research on the prevention and treatment of IBD by TCM by restoring Th17/Treg has also shown promising results. The characteristics of the Th17/Treg balance and its role in the pathogenesis of IBD, as well as the role of TCM in regulating the Th17/Treg imbalance, are analyzed. The research results are expected to provide a theoretical basis for the clinical treatment and pathology mechanism research of IBD.

Targeting Lineage-Specific Transcription Factors and Cytokines of the Th17/Treg Axis by Novel 1,3,4-Oxadiazole Derivatives of Pyrrolo[3,4-d]pyridazinone Attenuates TNBS-Induced Experimental Colitis

The pharmacotherapy of inflammatory bowel disease (IBD) is still not fully effective and safe. Attempts to search for new IBD drugs remain an incessant research aim. One of the novel approaches is targeting the developmental pathway molecules and effector cytokines of Th17/Treg axis. This study aimed to elucidate the impact of new pyrrolo[3,4-d]pyridazinone derivatives, compounds 7b, 10b, or 13b, on the course of experimental colitis in rats and to assess whether these new compounds may influence Th17/Treg axis. Rats were pretreated with studied compounds intragastrically before intrarectal administration of 2,4,6-trinitrobenzenesulfonic acid used for colitis induction. Body weight loss, disease activity index, colon index, and colon tissue damage were analyzed to evaluate the severity of colitis. The colonic levels of RORγt, STAT3, CCR6, Foxp3, IL-6, IL-10, IL-17, TNF-α, IL-23, and PGE₂ were assessed. Pretreatment with compounds 7b and 13b alleviated the severity of colitis and concomitantly counteracted the increased levels of RORγt, STAT3, CCR6, IL-6, IL-17, IL-23, TNF-α, and PGE₂. The beneficial effect of compounds 7b and 13b may be due to the decrease in the levels of Th17-specific transcription factors and cytokines. The studied compounds might therefore constitute a promising therapeutic strategy in Th17/Treg imbalance-driven inflammatory conditions such as IBD.

Research progress on the pathogenesis of Graves’ ophthalmopathy: Based on immunity, noncoding RNA and exosomes

Graves’ ophthalmopathy (GO), also known as thyroid-associated ophthalmopathy, is a common potentially vision-threatening organ-specific autoimmune disease and the most common extrathyroidal manifestation of Graves’ disease. It can happen to those who have hyperthyroidism or euthyroidism. At present, the pathogenesis of GO has not been fully elucidated, and the majority of clinical treatments are symptomatic. Therefore, we are eager to discover any new therapeutic strategies that target the etiology of GO. To provide fresh ideas for the creation of new therapeutic techniques, this study primarily discusses the research state and progress of GO-related pathogenesis from the perspectives of GO’s cellular immunity, autoantigens, non-coding RNAs, and exosomes.

The emerging microbiome-based approaches to IBD therapy: From SCFAs to urolithin A

Inflammatory bowel disease (IBD) is a group of chronic gastrointestinal inflammatory conditions which can be life-threatening, affecting both children and adults. Crohn's disease and ulcerative colitis are the two main forms of IBD. The pathogenesis of IBD is complex and involves genetic background, environmental factors, alteration in gut microbiota, aberrant immune responses (innate and adaptive), and their interactions, all of which provide clues to the identification of innovative diagnostic or prognostic biomarkers and the development of novel treatments. Gut microbiota provide significant benefits to its host, most notably via maintaining immunological homeostasis. Furthermore, changes in gut microbial populations may promote immunological dysregulation, resulting in autoimmune diseases, including IBD. Investigating the interaction between gut microbiota and immune system of the host may lead to a better understanding of the pathophysiology of IBD as well as the development of innovative immune- or microbe-based therapeutics. In this review we summarized the most recent findings on innovative therapeutics for IBD, including microbiome-based therapies such as fecal microbiota transplantation, probiotics, live biotherapeutic products, short-chain fatty acids, bile acids, and urolithin A.

Effect of Intervention of Probiotics in Advance on Treg/Th17 in Premature Mice

To preliminarily understand the differentiation characteristics of regulatory T cells (Tregs) and Th17 at a different time in preterm mice, the impacts of probiotics on immune function progression, as well as the correlation of probiotics with Tregs and Th17. On embryonic day 18 of gestation, a mouse model of preterm birth was built using mifepristone (RU486). Following IPI of RU486, newborn mice were randomized to probiotics or NS gavage administration. Full-term newborn mice were given the same dose of NS gavage administration. Phenotypic analysis of peripheral immune cell frequency was performed using flow cytometry. Cytokine measurements were phenotyped by enzyme-linked immunosorbent assays. On the 14th and 21st days after birth, the highest and lowest expressions of Foxp3, the Treg transcription factor, were observed in full-term mice and premature mice by NS gavage administration, respectively, while the opposite trend was found in the Th17 transcription factor IL-17.IL-2, IL-6, and TGF-β rose with age but showed different trends among the three groups. IL-2 is the highest in full-term mice and the lowest in premature mice. IL-6 and TGF-β is the lowest in full-term mice and the highest in premature mice. Probiotics are beneficial to the development and maturation of the immune system, which may play a role in regulating the ratio of Treg/Th17. Probiotic preintervention can effectively promote the differentiation of Treg and inhibit the differentiation of Th17 in premature mice. Its mechanism of action may play a biological role by regulating cytokine (IL-2, IL-6, and TGF-β) secretions.

P2 Receptors: Novel Disease Markers and Metabolic Checkpoints in Immune Cells

Extracellular ATP (eATP) and P2 receptors are novel emerging regulators of T-lymphocyte responses. Cellular ATP is released via multiple pathways and accumulates at sites of tissue damage and inflammation. P2 receptor expression and function are affected by numerous single nucleotide polymorphisms (SNPs) associated with diverse disease conditions. Stimulation by released nucleotides (purinergic signalling) modulates several T-lymphocyte functions, among which energy metabolism. Energy metabolism, whether oxidative or glycolytic, in turn deeply affects T-cell activation, differentiation and effector responses. Specific P2R subtypes, among which the P2X7 receptor (P2X7R), are either up- or down-regulated during T-cell activation and differentiation; thus, they can be considered indexes of activation/quiescence, reporters of T-cell metabolic status and, in principle, markers of immune-mediated disease conditions.

Cytokine dynamics and targeted immunotherapies in autoimmune encephalitis

Autoimmune encephalitides constitute a diverse group of immune-mediated central nervous system disorders mainly characterized by the presence of antibodies targeting neuronal or glial antigens. Despite the notable contribution of antibody discovery to the understanding of their physiopathology, the specific immune cells and inflammatory mediators involved in autoimmune encephalitis are still poorly defined. However, cytokines have recently emerged as crucial signalling molecules in the pathogenesis of autoimmune encephalitis. Cytokines are biologically active, soluble, low-molecular-weight proteins or glycoproteins involved in a wide variety of physiological functions, including central nervous system development and homeostasis, immune surveillance, as well as proliferation and maturation of immune cells. Since unbalanced cytokine expression is considered a hallmark of many autoimmune central nervous system disorders, their identification and quantification has become an essential element in personalized medicine applied to the field of neuroimmunology. Several studies have explored the cytokine profile of autoimmune encephalitis, but their interpretation and comparison is challenging due to their small sample sizes and extremely high heterogeneity, especially regarding the cytokines analysed, type of sample used, and associated neural antibody. Only the cytokine profile of anti-N-methyl-D-aspartate receptor encephalitis has extensively been investigated, with findings suggesting that, although humoral immunity is the main effector, T cells may also be relevant for the development of this disorder. A better understanding of cytokine dynamics governing neuroinflammation might offer the opportunity of developing new therapeutic strategies against specific immune cells, cytokines, antibodies, or intracellular signalling cascades, therefore leading to better outcomes and preventing undesired side effects of the presently used strategies. In this review, we first summarize the current knowledge about the role of cytokines in the pathogenesis of autoimmune encephalitis, combining theoretical analysis with experimental validations, to assess their suitability as clinical biomarkers. Second, we discuss the potential applicability of the novel targeted immunotherapies in autoimmune encephalitis depending on the immunobiology of the associated antibody, their limitations, as well as the main limitations that should be addressed in future studies.

T Cell Extracellular Traps: Tipping the Balance Between Skin Health and Disease

The role of extracellular traps (ETs) in the innate immune response against pathogens is well established. ETs were first identified in neutrophils and have since been identified in several other immune cells. Although the mechanistic details are not yet fully understood, recent reports have described antigen-specific T cells producing T cell extracellular traps (TETs). Depending on their location within the cutaneous environment, TETs may be beneficial to the host by their ability to limit the spread of pathogens and provide protection against damage to body tissues, and promote early wound healing and degradation of inflammatory mediators, leading to the resolution of inflammatory responses within the skin. However, ETs have also been associated with worse disease outcomes. Here, we consider host-microbe ET interactions by highlighting how cutaneous T cell-derived ETs aid in orchestrating host immune responses against Cutibacterium acnes (C. acnes), a commensal skin bacterium that contributes to skin health, but is also associated with acne vulgaris and surgical infections following joint-replacement procedures. Insights on the role of the skin microbes in regulating T cell ET formation have broad implications not only in novel probiotic design for acne treatment, but also in the treatment for other chronic inflammatory skin disorders and autoimmune diseases.

Prenatal and early life factors and type 1 diabetes

BACKGROUND

The prevalence of type 1 diabetes is increasing worldwide, suggesting that unknown environmental factors are becoming increasingly important in its pathogenesis.

AIM

The aim of the study was to investigate the possible role of a number of prenatal and perinatal factors in the aetiology of type 1 diabetes.

METHODS

Mothers of patients diagnosed with type 1 diabetes (cases) and mothers of children born on the same day and of the same sex as type 1 diabetes patients (controls) were interviewed on a number of prenatal and perinatal factors of interest.

RESULTS

Hand washing prior to eating, frequency of bathing and total stress score were found to be positively associated with the development of type 1 diabetes on univariate analyses. Hand-washing prior to eating and frequency of house cleaning were independently associated with an increased risk of type 1 diabetes, whilst getting dirty was associated with a reduced risk in multivariate analyses. There was no association of type 1 diabetes to removing of outdoor shoes indoors or to the age of first attendance to school or pre-school. There were also no significant associations to parental smoking, parental age, birth order, infant feeding, antibiotic use, mode of delivery or birth weight.

CONCLUSION

Our data suggest that factors that affect the skin or gut microbiome might be more important than infections or factors affecting the microbiome at other sites.

Regulatory role of short-chain fatty acids in inflammatory bowel disease

Inflammatory bowel disease (IBD) comprises a group of chronic inflammatory disorders of the gastrointestinal tract. Accumulating evidence shows that the development of IBD is always accompanied by the dysbiosis of the gut microbiota (GM), causing a decrease in prebiotic levels and an increase in harmful metabolite levels. This leads to persistent immune response and inflammation in the intestine, greatly impairing the physiological function of the gastrointestinal tract. Short-chain fatty acids (SCFAs) are produced by probiotic gut bacteria from a fiber-rich diet that cannot be digested directly. SCFAs with significant anti-inflammatory functions regulate immune function and prevent an excessive immune response, thereby delaying the clinical progression of IBD. In this review, we summarize the generation of SCFAs and their potential therapeutic effects on IBD. Furthermore, we suggest that SCFAs may modulate innate immune recognition and cytokine production to intervene in the progression of IBD. Additional randomized controlled trials and prospective cohort studies should also investigate the clinical impact of SCFA. Video Abstract.