Efficacy and safety of guselkumab in patients with active psoriatic arthritis who had inadequate efficacy and/or intolerance to one prior tumor necrosis factor inhibitor: study protocol for SOLSTICE, a phase 3B, multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Tumor necrosis factor inhibitors (TNFi) are frequently chosen as the first biologic for patients with psoriatic arthritis (PsA). Given that many patients with PsA are TNFi inadequate responders (TNF-IR; either inadequate efficacy or intolerance), treatments utilizing alternative mechanisms of action are needed. In phase 3 studies, the fully human interleukin (IL)-23p19 subunit-inhibitor, guselkumab, was efficacious in patients with active PsA, including TNFi-IR. Efficacy was generally consistent between TNFi-naïve and TNFi-experienced cohorts; however, in the latter, higher response rates have been observed with the Q4W dosing regimen relative to the Q8W dosing regimen for some endpoints, suggesting the need to evaluate whether more frequent dosing may provide an incremental clinical benefit for TNFi-IR patients.

METHODS

The phase 3b SOLSTICE study will assess guselkumab efficacy and safety in TNFi-IR PsA patients. Eligibility criteria include a PsA diagnosis for ≥ 6 months; active disease (≥ 3 swollen, ≥ 3 tender joints, C-reactive protein ≥ 0.3 mg/dL); and inadequate efficacy with, and/or intolerance to, one prior TNFi. Participants will be randomized 1:1:1 to guselkumab Q4W or Q8W or placebo→guselkumab Q4W (at Week 24). The primary endpoint is the proportion of patients achieving ≥ 20% improvement in the American College of Rheumatology criteria (ACR20) at Week 24. Major secondary endpoints include ACR50, ACR70; an Investigator's Global Assessment (IGA) of psoriasis score of 0/1 plus ≥ 2-grade reduction and ≥ 90% improvement in Psoriasis Area and Severity Index (both among patients with ≥ 3% body surface area affected by psoriasis and baseline IGA ≥ 2); minimal/very low disease activity; and changes from baseline in Health Assessment Questionnaire-Disability Index, the 36-item Short-Form Health Survey Physical Component Summary, and Functional Assessment of Chronic Illness Therapy-Fatigue scores. The target sample size (N = 450) is estimated to provide > 90% power in detecting differences between each guselkumab group and the placebo group for the primary endpoint assuming a 2-sided α = 0.05. Cochran-Mantel-Haenszel testing and analyses of covariance will be used to compare efficacy for binary and continuous endpoints, respectively.

DISCUSSION

Findings from the phase 3b SOLSTICE study, the design of which was informed by results from previously conducted phase 3 studies, is expected to provide important efficacy and safety information on guselkumab therapy in TNFi-IR patients with PsA.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov, NCT04936308, on 23 June 2021.

Molecular characterization, expression analysis and function identification of Pf_IL-12p35, Pf_IL-23p19 and Pf_IL-12p40 genes in yellow catfish (Pelteobagrus fulvidraco)

The interleukin-12 (IL-12) family is a class of heterodimeric cytokines that play crucial roles in pro-inflammatory and pro-stimulatory responses. Although some IL-12 and IL-23 paralogues have been found in fish, their functional activity in fish remains poorly understood. In this study, Pf_IL-12p35a/b, Pf_IL-23p19 and Pf_IL-12p40a/b/c genes were cloned from yellow catfish (Pelteobagrus fulvidraco), four α-helices were found in Pf_IL-12p35a/b and Pf_IL-23p19. The transcripts of these six genes were relatively high in mucus and immune tissues of healthy individuals, and in gill leukocytes. Following Edwardsiella ictaluri infection, Pf_IL-12p35a/b and Pf_IL-23p19 mRNAs were induced in brain and kidney (or head kidney), Pf_IL-12p40a mRNA was induced in gill, and Pf_IL-12p40b/c mRNAs were induced in brain and liver (or skin). The mRNA expression of these genes in PBLs was induced by phytohaemagglutinin (PHA) and polyinosinic-polycytidylic acid (poly I:C), while lipopolysaccharides (LPS) induced the mRNA expression of Pf_IL-12p35a and Pf_IL-12p40b/c in PBLs. After stimulation with recombinant (r) Pf_IL-12 and rPf_IL-23 subunit proteins, either alone or in combination, mRNA expression patterns of genes related to T helper cell development exhibited distinct differences. The results suggest that Pf_IL-12 and Pf_IL-23 subunits may play important roles in regulating immune responses to pathogens and T helper cell development.

Increased synthesis and intestinal expression of IL-39 in patients with inflammatory bowel disease

IL-39 (Interleukin-39) is a heterodimeric cytokine composed of IL-23p19 and EBI3 (Epstein-Barr virus-induced gene 3) subunits. Despite the evidence that correlates the role of IL-39 in regulating inflammation, its expression in the intestinal microenvironment of IBD (inflammatory bowel disease) patients is still unknown. Thus, this work was focused on characterizing relative mRNA (messenger RNA) IL-39 expression and intestinal synthesis in IBD patients. This study includes 37 patients diagnosed with ulcerative colitis (UC), 15 with Chron's disease (CD), and 22 controls. Gene expression of IL-39 subunits (IL-23p19/EBI3) was measured by RT-PCR (real time polymerase chain reaction). Intestinal synthesis was evaluated by immunohistochemistry and serum levels by ELISA. Statistical analysis was done using Prism GraphPad V6. Relative mRNA IL-39 expression was increased in patients with active UC and active CD compared to the remission UC, remission CD, and control group. High levels of relative mRNA expression of IL-39 (IL-23p19 subunit) were associated with histological activity. IHQ analysis showed increased IL-39 production in mucosa, submucosa, muscular, and serosa layer of patients with active disease. IL-39 serum production was increased in patients with UC. IL-39 gene's upregulation was found in patients with active IBD and was associated with severe histological activity in UC. This is the first report regarding the role of IL-39 in patients with IBD. The findings suggest that IL-39 might play a role as an inflammatory mediator in active IBD and could be considered a new alternative in treating this condition.

Plasminogen activating inhibitor-1 promotes angiogenesis in cutaneous angiosarcomas

Plasminogen activating inhibitor-1 (PAI-1) is associated with poor clinical outcomes, and elevated levels of PAI-1 in both tissue and serum are correlated with poor response to therapy in various cancers, including skin cancer. Cutaneous angiosarcoma (CAS) is a vascular tumor histologically characterized by detachment of endothelial cell-derived tumor cells. Since CAS expresses multiple angiogenic growth factors and has increased expressions of angiogenic receptor tyrosine kinase transcripts including VEGFR1/2/3, angiogenesis-promoting factors are potential drug targets in CAS. In this study, the expression of PAI-1 was examined in 31 cases of CAS, and the immunomodulatory effects of PAI-1 on a human CAS cell line, ISO-HAS-B, were evaluated. We found that, of the angiogenesis-promoting factors, PAI-1 was expressed in almost all cases of CAS, and PAI-1 increased the mRNA expressions of IL-23p19, VEGF-C, CXCL5 and CCL20 on ISO-HAS-B. Moreover, PAI-1 stimulated ISO-HAS-B culture supernatant promoted favourable tube networks, suggesting that these tumor-derived factors promote the pro-angiogenic effect on tumor development. In addition, IL-23p19 was expressed in 61.3% of cases, whereas VEGF-C was expressed in 41% of cases. The results of the present study suggest that PAI-1 promotes angiogenesis that results in tumor progression in CAS.

Efficacy and safety of guselkumab in biologic-naïve patients with active axial psoriatic arthritis: study protocol for STAR, a phase 4, randomized, double-blinded, placebo-controlled trial

Background

Axial involvement constitutes a specific domain of psoriatic arthritis (PsA). Interleukin (IL)-23 inhibitors have demonstrated improvement in axial PsA (axPsA) symptoms, but have not shown efficacy in treating ankylosing spondylitis (AS), suggesting differences in axPsA processes and treatments. In a post hoc, pooled analysis of patients with investigator- and imaging-confirmed sacroiliitis in two phase 3, randomized, placebo-controlled studies (DISCOVER-1 and DISCOVER-2), patients treated with guselkumab, an IL-23p19 inhibitor, had greater axial symptom improvements compared with placebo. Confirmatory imaging at baseline was restricted to the sacroiliac (SI) joints, occurred prior to/at screening, and was locally read.

Methods

The STAR study will prospectively assess efficacy outcomes in PsA patients with magnetic resonance imaging (MRI)-confirmed axial inflammation. Eligible, biologic-naïve patients with PsA (N =  405) for ≥ 6 months and active disease (≥ 3 swollen and ≥ 3 tender joints, C-reactive protein [CRP] ≥ 0.3 mg/dL) despite prior non-biologic disease-modifying antirheumatic drugs, apremilast, and/or nonsteroidal anti-inflammatory drugs will be randomized (1:1:1) to guselkumab every 4 weeks (Q4W); guselkumab at week (W) 0, W4, then every 8 weeks (Q8W); or placebo with crossover to guselkumab at W24, W28, then Q8W. Patients will have Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score ≥ 4, spinal pain component score (0–10 visual analog scale) ≥ 4, and screening MRI-confirmed axial involvement (positive spine and/or SI joints according to centrally read Spondyloarthritis Research Consortium of Canada [SPARCC] score ≥ 3 in ≥ 1 region). The primary endpoint is mean change from baseline in BASDAI at W24; multiplicity controlled secondary endpoints at W24 include AS Disease Activity Score employing CRP (ASDAS), Disease Activity Index for PsA (DAPSA), Health Assessment Questionnaire – Disability Index (HAQ-DI), Investigator’s Global Assessment of skin disease (IGA), and mean changes from baseline in MRI SI joint SPARCC scores. Centrally read MRIs of spine and SI joints (scored using SPARCC) will be obtained at W0, W24, and W52, with readers blinded to treatment group and timepoint. Treatment group comparisons will be performed using a Cochran-Mantel-Haenszel or chi-square test for binary endpoints and analysis of covariance, mixed model for repeated measures, or constrained longitudinal data analysis for continuous endpoints.

Discussion

This study will evaluate the ability of guselkumab to reduce both axial symptoms and inflammation in patients with active PsA.

Trial registration

This trial was registered at ClinicalTrials.gov, NCT04929210, on 18 June 2021.

Protocol version: Version 1.0 dated 14 April 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06589-y.

IL-23 Blockade in Anti-TNF Refractory IBD: From Mechanisms to Clinical Reality

Increasing insights into the immunopathogenesis of inflammatory bowel diseases [IBD] have led to the advent of targeted therapies that inhibit crucial mediators of the inflammatory process, thereby widening our available therapeutic armamentarium. Anti-tumour necrosis factor [anti-TNF] agents are still a mainstay of our therapeutic endeavours and the introduction of corresponding biosimilars has further widened their use. Nevertheless, only a subgroup of treated patients benefit from the initiated treatment and there is secondary non-response in the course of therapy. Initiation of subsequent therapy often poses a challenge to the treating physician, as non-response to primary anti-TNF treatment generally characterizes a patient group that is more treatment-resistant, which may be due to the immunological impregnation by prior anti-TNF exposure. At present, there is currently no guidance for the most appropriate second-line therapy after anti-TNF failure. Here, we review the efficacy of secondary biological therapy in anti-TNF-treated patients. We focus on and assess available clinical trial data of the emerging substance class of IL-23p19 inhibitors, which have demonstrated remarkable efficacy not only in anti-TNF-naïve but also refractory patients. We present molecular mechanisms that drive IL-23-mediated resistance to ongoing anti-TNF therapy and discuss the dynamic fluidity of the mucosal cytokine network in the course of therapy that perpetuates the mucosal inflammatory reaction. Translation of these findings into clinical practice might finally lead to initiation of the most appropriate therapy at the right time of the individual disease course, which would have important implications for the patient's probability of response to treatment.

Absolute Psoriasis Area and Severity Index as a valuable marker to determine initial treatment response in psoriasis patients treated with guselkumab in routine clinical care

Guselkumab is an anti-interleukin-23p19 monoclonal antibody approved as a first-line medication in patients with moderate-to-severe plaque-type psoriasis and second-line in active psoriatic arthritis. In the clinic, patients who have shown a lack of previous treatment efficacy and/or tolerability are often prescribed guselkumab. These patients generally have less severe psoriasis compared to clinical trial cohorts, reflected in lower Psoriasis Area and Severity Index (PASI). To evaluate treatment response in a real-world setting, we conducted a multicenter-retrospective chart review in three specialized dermatological centers. Seventy-four patients who received guselkumab treatment were included in the study and baseline characteristics were described. The mean PASI at baseline was 13.0 (± 6.7). After 12 weeks of treatment 40 patients could be followed up at the participating centers and efficacy was assessed: 72.5% of these patients achieved an absolute PASI ≤5 (55.0% ≤3; 42.5% ≤2) whereas only 57.5% of patients were able to gain a delta PASI reduction of at least 75%. Using the absolute PASI as a treatment goal rather than response rate revealed that guselkumab was highly effective in this real-world setting. In conclusion, the absolute PASI proved to be a more valuable tool to measure treatment outcome.

Long-term efficacy and safety of tildrakizumab in Japanese patients with moderate to severe plaque psoriasis: Results from a 5-year extension of a phase 3 study (reSURFACE 1)

The three part, double‐blind, randomized, controlled reSURFACE 1 trial and extension study (NCT01722331) evaluated efficacy and safety of tildrakizumab in adults with moderate to severe plaque psoriasis. Patients with ≥50% improvement from baseline in Psoriasis Area and Severity Index (PASI 50) following treatment with tildrakizumab 100 mg (TIL100) or 200 mg (TIL200) could enter the optional long‐term extension study and continue treatment at the same dose for an additional 192 weeks. This subgroup analysis assessed the long‐term efficacy and safety of tildrakizumab treatment for Japanese patients enrolled in reSURFACE 1 for up to 5 years of treatment. The primary efficacy outcomes were the proportions of patients who maintained PASI 75 and Physician Global Assessment (PGA) clear or minimal with ≥2‐grade reduction from baseline (PGA 0/1) from base study week 64 to extension week 192. Secondary outcomes were the proportion of patients who maintained PASI 90/100 from base study week 64 to extension week 192. Adverse events (AEs) were monitored throughout the study and for up to 20 weeks after the last study visit. Of the 120 Japanese patients who entered the reSURFACE 1 extension study, 43 (79.6%) patients receiving tildrakizumab 100 mg and 58 (87.9%) patients receiving tildrakizumab 200 mg completed the extension study. Of all Japanese patients with PASI 75/90/100 and PGA 0/1 at week 64, 85%/88% receiving TIL100/TIL200 maintained PASI 75, 70%/96% maintained PASI 90, 63%/67% maintained PASI 100, and 68%/72% maintained PGA 0/1 at extension week 192. AEs led to discontinuation in 1.7 patients per 100 patient‐years (P100PY) receiving tildrakizumab 100 mg and 0.8 P100PY receiving tildrakizumab 200 mg. Incidences of severe infections, malignancies, confirmed major adverse cardiac events, and hypersensitivity reactions were low in both treatment groups. Through 5 years of treatment, tildrakizumab maintained efficacy and was well tolerated with low rates of AEs of special interest.

Tildrakizumab: An Evidence-Based Review of Its Use in the Treatment of Moderate-to-Severe Chronic Plaque Psoriasis

Psoriasis is a common immune-mediated chronic inflammatory disease, and observations have pointed toward the IL-23/Th17 cell axis as having a key role in the pathogenesis of psoriasis. This new immunological understanding of the pathogenesis has been translated into targeted and highly effective biologic therapies. Tildrakizumab is a humanized IgG1/k monoclonal antibody targeting the p19 unit of IL-23 and has been registered for the treatment of patients with moderate-to-severe chronic plaque psoriasis in adults since 2018. This review provides an overview of the efficacy and safety of tildrakizumab, focusing on the results from clinical trials. In both Phase II and III trials, tildrakizumab 100 and 200 mg was significantly more efficacious than both placebo and etanercept at week 12. The effect of tildrakizumab continued to increase until week 28. Long-term follow-up showed high levels of efficacy for up to 3 years. Despite no difference between 100 and 200 mg in Phase III studies, subgroup analyses showed better efficacy when treated with 200 mg in patients with bodyweight ≥90 kg. The overall drug safety was good, and besides discrete higher incidence of nasopharyngitis, the conducted clinical trials show that tildrakizumab was very well tolerated without any safety concerns. Compared to other IL-23p19 inhibitors, tildrakizumab seemed to have slightly lower efficacy. However, to determine its position in the treatment algorithm of psoriasis, head-to-head trials with other IL-17, IL-12/23, and IL-23 inhibitors and long-term real-world data are required.

Interleukin-23 is constitutively expressed in the human annulus in vivo and in vitro, and is up-regulated in vitro by TNF-α

Interleukin-23 (IL-23, IL-23p19) is a proinflammatory cytokine in the IL-12-related family. Although inflammatory cells in herniated discs have been shown to contain IL-23, little is known about the presence and role of IL-23 in human disc cells. We analyzed disc specimens for IL-23 localization using immunohistochemistry in control, herniated and non-herniated discs from which annulus fibrosus (annulus) cells were isolated and cultured to identify IL-23 gene expression and production. Microarray analysis was used to assess the expression of IL-23 in disc tissue and in cells exposed to two proinflammatory cytokines, IL-1ß and TNF-α. IL-23 was present in annulus cells at the protein level and its expression was up-regulated significantly in herniated compared to control disc tissue. Direct measurement of medium components confirmed production of IL-23 and its receptor, IL-23R, by annulus cells in vitro. Annulus cells in three-dimensional culture exposed to TNF-α, but not IL-1ß, resulted in significant up-regulation of IL-23 expression compared to control cells. Our findings are evidence for the constitutive presence of IL-23 in the human disc and that its expression in vitro is modified by exposure to TNF-α.

Treatment of plaque psoriasis with IL-23p19 blockers: A systematic review and meta-analysis

OBJECTIVES

Interleukin(IL)-23 is a key cytokine in the pathogenesis of psoriasis, this meta-analysis was to analyze the efficacy and safety of IL-23p19 blockers in patients with plaque psoriasis.

METHODS

A systematic review of the literature was performed to collect double-blind randomized controlled trials(RCTs). The pooled relative risk(RR) with 95% confidence interval(CI) was calculated. All analyses were conducted with intention-to-treat basis.

RESULTS

A total of 13 studies contained 5155 plaque psoriasis patients were included in our meta-analysis. The results indicated that IL-23p19 blockers had better efficacy than placebo for Psoriasis Area Severity Index score reductions from baseline of 75% or more (PASI75) (RR = 11.47, P < 0.001) and static Physician's Global Assessment score of 0 or 1(sPGA0/1) (RR = 11.32, P < 0.001). IL-23p19 blockers have similar safety with placebo about the incidence of adverse events(AEs) (RR = 1.22, P = 0.096) and serious adverse events(SAEs) (RR = 2.93, P = 0.965), but IL-23p19 blockers carried an increased incidence rate of infections (RR = 1.39, P < 0.001). While compared with adalimumab and ustekinumab, IL-23p19 blockers were more effective and had the similar tolerance. Among three IL-23p19 blockers, guselkumab was the most efficacious treatments, and risankizumab was better tolerated than the others.

CONCLUSION

The IL-23p19 blockers have excellent efficacy and great safety in plaque psoriasis patients, but long-term safety remains to be determined.

Profile of tildrakizumab-asmn in the treatment of moderate-to-severe plaque psoriasis: evidence to date

Plaque psoriasis is an immune-mediated skin disease that affects roughly 3% of adults in the United States. Advances over the past 20 years in understanding the immune-mediated pathophysiology of psoriasis have led to the development of targeted biologic therapies for this condition. Currently, biologic medications approved for the treatment of plaque psoriasis include tumor necrosis factor α inhibitors, interleukin (IL)-17 or IL-17 receptor inhibitors, IL-12/23 inhibitors, and IL-23 inhibitors. Tildrakizumab-asmn is a monoclonal antibody that targets the p19 subunit of IL-23 and is approved for use in adult patients with moderate-to-severe plaque psoriasis who are candidates for systemic therapy or phototherapy. This article reviews the current pharmacologic, efficacy, and safety data on tildrakizumab-asmn.

Expression and Function of IL12/23 Related Cytokine Subunits (p35, p40, and p19) in Giant-Cell Arteritis Lesions: Contribution of p40 to Th1- and Th17-Mediated Inflammatory Pathways

Background

Giant-cell arteritis (GCA) is considered a T helper (Th)1- and Th17-mediated disease. Interleukin (IL)-12 is a heterodimeric cytokine (p35/p40) involved in Th1 differentiation. When combining with p19 subunit, p40 compose IL-23, a powerful pro-inflammatory cytokine that maintains Th17 response.

Objectives

The aims of this study were to investigate p40, p35, and p19 subunit expression in GCA lesions and their combinations to conform different cytokines, to assess the effect of glucocorticoid treatment on subunit expression, and to explore functional roles of p40 by culturing temporal artery sections with a neutralizing anti-human IL-12/IL-23p40 antibody.

Methods and results

p40 and p19 mRNA concentrations measured by real-time RT-PCR were significantly higher in temporal arteries from 50 patients compared to 20 controls (4.35 ± 4.06 vs 0.51 ± 0.75; p < 0.0001 and 20.32 ± 21.78 vs 4.17 ± 4.43 relative units; p < 0.0001, respectively). No differences were found in constitutively expressed p35 mRNA. Contrarily, p40 and p19 mRNAs were decreased in temporal arteries from 16 treated GCA patients vs those from 34 treatment-naïve GCA patients. Accordingly, dexamethasone reduced p40 and p19 expression in cultured arteries. Subunit associations to conform IL-12 and IL-23 were confirmed by proximity-ligation assay in GCA lesions. Immunofluorescence revealed widespread p19 and p35 expression by inflammatory cells, independent from p40. Blocking IL-12/IL-23p40 tended to reduce IFNγ and IL-17 mRNA production by cultured GCA arteries and tended to increase Th17 inducers IL-1β and IL-6.

Conclusion

IL-12 and IL-23 heterodimers are increased in GCA lesions and decrease with glucocorticoid treatment. p19 and p35 subunits are much more abundant than p40, indicating an independent role for these subunits or their potential association with alternative subunits. The modest effect of IL-12/IL-23p40 neutralization may indicate compensation by redundant cytokines or cytokines resulting from alternative combinations.

Tolerogenic dendritic cells produced by lentiviral-mediated CD40- and interleukin-23p19-specific shRNA can ameliorate experimental autoimmune encephalomyelitis by suppressing T helper type 17 cells

Down-regulation of soluble or membrane-bound co-stimulatory molecules by RNAi in dendritic cells can prevent the activation of immune responses. Therefore, this study was designed to evaluate the therapeutic efficacy of bone marrow-derived DCs (BMDCs) transduced with lentiviral vectors to permanently expressed shRNA specific for CD40 (CD40LV-DCs) and/or p19 subunit of interleukin (IL)-23 (p19LV-DCs) mRNAs in experimental autoimmune encephalomyelitis (EAE). In-vitro studies showed that double-transduced BMDCs (CD40(+) p19LV-DCs) resemble tolerogenic DCs due to profound down-regulation of CD40, lower expression of proinflammatory cytokines (IL-6 and IL-12), increased IL-10 production and stronger stimulation of myelin oligodendrocyte glycoprotein (MOG)35-55 -specific T cells for production of IL-10 compared with CD40LV-DCs, p19LV-DCs and BMDCs transduced with control lentiviral vector (CoLV-DCs). Moreover, injection of transduced CD40(+) p19LV- BMDCs in EAE mice resulted in more reduction in clinical score, significant reduction in IL-17 or increased production of IL-10 by mononuclear cells derived from the lymph nodes or spinal cord compared with CoLV-DCs-treated EAE mice. In conclusion, simultaneous knock-down of CD40 and IL-23 production by BMDCs may represent a promising therapeutic tool for the treatment of IL-17-dependent autoimmune diseases, including multiple sclerosis.

Downregulation of microRNA-107 in intestinal CD11c(+) myeloid cells in response to microbiota and proinflammatory cytokines increases IL-23p19 expression

Commensal flora plays an important role in the development of the mucosal immune system and in maintaining intestinal homeostasis. However, the mechanisms involved in regulation of host-microbiota interaction are still not completely understood. In this study, we examined how microbiota and intestinal inflammatory conditions regulate host microRNA expression and observed lower microRNA-107 (miR-107) expression in the inflamed intestines of colitic mice, compared with that in normal control mice. miR-107 was predominantly reduced in epithelial cells and CD11c(+) myeloid cells including dendritic cells and macrophages in the inflamed intestines. We demonstrate that IL-6, IFN-γ, and TNF-α downregulated, whereas TGF-β promoted, miR-107 expression. In addition, miR-107 expression was higher in the intestines of germ-free mice than in mice housed under specific pathogen-free conditions, and the presence of microbiota downregulated miR-107 expression in DCs and macrophages in a MyD88- and NF-κB-dependent manner. We determined that the ectopic expression of miR-107 specifically repressed the expression of IL-23p19, a key molecule in innate immune responses to commensal bacteria. We concluded that regulation of miR-107 by intestinal microbiota and proinflammatory cytokine serve as an important pathway for maintaining intestinal homeostasis.