Phase 1 and 2 Randomized Clinical Studies Determine Lack of Efficacy for Anti-IL-17C Antibody MOR106 in Moderate-Severe Atopic Dermatitis.

Interleukin 17C (IL-17C) modulates epithelial inflammation and has a possible role in atopic dermatitis (AD) pathology. Four randomized clinical studies (Phase 1 and 2) investigated the safety, tolerability, efficacy, and pharmacokinetic profile of the anti-IL-17C monoclonal antibody MOR106 for up to 12 weeks (NCT03568071: n = 207 adults with moderate-severe AD; NCT03689829 Part 1: n = 32 healthy males; NCT03689829 Part 2: n = 44 adults with moderate-severe AD; and NCT03864627: n = 76 adults with moderate-severe AD). In these studies, MOR106 was either administered intravenously (i.v.) every 2 or 4 weeks at doses between 1-10 mg/kg, or subcutaneously (s.c.), either as a single dose or doses every 2 weeks at 320 mg. Overall, MOR106 was well-tolerated, and the safety profile was consistent with monoclonal antibodies approved for AD. Bioavailability following s.c. dosing was 55%, and steady-state drug levels were reached at 2-4 weeks. Ongoing studies were terminated following a futility analysis of the Phase 2 placebo-controlled dose-finding study (NCT03568071) due to a low probability for achieving the primary efficacy endpoint. Cumulatively, MOR106 demonstrated ineffectiveness for the treatment of AD, but its safety and pharmacokinetic characteristics warrant further drug development in other indications. Funding: sponsored by Galapagos NV; funded by Novartis AG.

Molecular characterization of fish cytokine IL-17C from Amphiprion clarkii and its immunomodulatory effects on the responses to pathogen-associated molecular patterns and bacterial challenges.

Interleukin 17C (IL17C) is a cytokine that regulates innate immunity by recruiting antimicrobial peptides and pro-inflammatory cytokines. In this study, we characterized properties of IL-17C from Amphiprion clarkii also known as yellowtail clownfish (AcIL-17C). The AcIL-17C gene is 489 base pairs long and encodes a 163 amino acid long protein. AcIL-17C includes a signal peptide for localization in the extracellular space and comprises the IL-17 domain. The transcription analysis revealed that AcIL-17C mRNA was ubiquitously expressed in 12 tested tissues. Blood cells treated with polyinosinic:polycytidylic acid (poly (I:C)), lipopolysaccharides (LPS), and Vibrio harveyi, AcIL-17C mRNA expression was upregulated at 6 h (following poly (I:C) and LPS treatments) and at 24 h post-injection (following all treatments). The downstream gene analysis of the epithelial fathead minnow (FHM) cells showed upregulated expression of genes, such as FHM_NK-Lysin, FHM_Hepcidin-1, FHM_Defensin-ß, encoding antimicrobial peptides, as well as of FHM_IL-1ß, FHM_TNF-A, FHM_IL-11, and FHM_STAT3 genes encoding inflammation-related proteins and IL-17C receptor genes FHM_IL-17RA, and FHM_IL-17RE at 12 and 24 h after treatment with AcIL-17C. The bacterial colony counting assay showed lower colony counts of Escherichia coli grown on FHM cells transfected with AcIL-17C carrying vector compared to those grown on control FHM cells. Further, AcIL-17C had a concentration-dependent positive effect on the survival of FHM cells infected with E. coli compared to the percentage of survived control cells. There has been a lack of studies characterizing the functions of teleost IL-17C. Therefore, these findings provide important information about the teleost host defense mechanisms and insights on the IL-17C-mediated antibacterial immunity.

IL-17C and IL-17RE Promote Wound Closure in a Staphylococcus aureus-Based Murine Wound Infection Model.

The epithelial cytokine interleukin-17C (IL-17C) mediates inflammation through the interleukin 17 receptor E (IL-17RE). Prior studies showed a detrimental role of IL-17C in the pathogenesis of immune-mediated skin diseases (e.g., psoriasis). Here, we examined the role of IL-17C/IL-17RE in wound closure in a Staphylococcus aureus wound infection model. We demonstrate that wound closure is significantly delayed in IL-17RE (Il-17re-/-)- and 17C (Il-17c-/-)-deficient mice. There was no significant difference between WT, Il-17re-/-, and Il-17c-/- mice in the absence of infection. Deficiency for IL-17RE and IL-17C did not significantly affect the elimination of bacteria. IL-17C expression was increased in the epidermis of human S. aureus-infected skin. Our results indicate that the IL-17C/IL-17RE axis contributes to the closure of infected wounds but does not contribute to the elimination of S. aureus.

miR-23a-3p is a Key Regulator of IL-17C-Induced Tumor Angiogenesis in Colorectal Cancer.

MicroRNAs (miRNAs) have emerged as key players in tumor angiogenesis. Interleukin-17C (IL-17C) was identified to promote colorectal cancer (CRC) progression. Therefore, we aimed to investigate the effect of IL-17C on tumor angiogenesis, the involvement of miR-23a-3p in IL-17C signaling, and the direct target gene of miR-23a-3p in CRC. In vitro and ex vivo angiogenesis, a mouse xenograft experiment, and immunostaining were performed to test the effect of IL-17C on tumor angiogenesis. ELISA, quantitative real time PCR, and gene silencing were used to uncover the underlying mechanism. IL-17C induced angiogenesis of intestinal endothelial cells, subsequently enhancing cell invasion and migration of DLD-1 cells. IL-17C-stimulated DLD-1 cells produced vascular endothelial growth factor (VEGF) to enhance angiogenesis. Moreover, IL-17C markedly accelerated xenograft tumor growth, which was manifested by substantially reduced tumor growth when treated with the VEGF receptor 2 inhibitor Ki8751. Accordingly, Ki8751 suppressed the expression of IL-17C-stimulated PECAM and VE-cadherin in xenografts. Furthermore, IL-17C activated STAT3 to increase the expression of miR-23a-3p that suppressed semaphorin 6D (SEMA6D) expression, thereby permitting VEGF production. Taken together, our study demonstrates that IL-17C promotes tumor angiogenesis through VEGF production via a STAT3/miR-23a-3p/SEMA6D axis, suggesting its potential as a novel target for anti-CRC therapy.

Interleukin-17A suppresses granular layer formation in a 3-D human epidermis model through regulation of terminal differentiation genes.

Immunotherapies targeting interleukin (IL)-17 greatly improve plaque psoriasis. Most previous studies on IL-17 focused on the T-helper (Th)17 immune response, but investigation of the effects of IL-17A on psoriatic epidermal structure are limited. Using an in vitro 3-D human epidermis model, we investigated the effects of IL-17A and IL-17C on morphological changes and gene expression. IL-17A directly suppressed the formation of the granular layer, whereas IL-17C did not. IL-17A significantly downregulated the gene expression of profilaggrin (FLG), which is a major component of keratohyalin granules in the granular layer. Global gene expression analysis of this 3-D epidermis model showed that both IL-17A and IL-17C upregulated S100A7A and type 1 interferon-related genes including MX1, IFI44L, XAF1 and IFIT1. However, only IL-17A directly downregulated keratinocyte differentiation-related and cornified envelope-related genes including FLG, LOR, C1ORF68, LCE1E, LCE1B, KRT10, CST6 and RPTN. In conclusion, IL-17A, a systemic inflammatory cytokine, affected keratinization in our 3-D epidermis model. In contrast, IL-17C, a locally produced cytokine, did not have strong effects on keratinization. Targeting IL-17A does not only reduce inflammation but it may also directly affect epidermal differentiation in psoriasis.

Chlamydia pneumoniae infection promotes vascular smooth muscle cell migration via c-Fos/interleukin-17C signaling.

Chlamydia pneumoniae (C. pneumoniae) infection is associated with the initiation and progression of atherosclerosis. The migration of vascular smooth muscle cell (VSMC) from the media to the intima is a key event in the development of atherosclerosis. Interleukin-17C (IL-17C) could enhance cell migration ability. The aim of our study is to investigate the role of IL-17C in C. pneumoniae infection-promoted VSMC migration, thereby possibly accelerating atherosclerosis. We firstly demonstrated that C. pneumoniae infection significantly increased IL-17C expression in VSMCs in the atherosclerotic lesion area from ApoE deficient mice. Our in vitro study further showed that IL-17C is required for C. pneumoniae infection-promoted VSMC migration, and its expression could be regulated by c-Fos through phosphorylating extracellular signal-regulated kinase (ERK). Unexpectedly, in the present study, we also found that IL-17C is critical for C. pneumoniae infection-induced c-Fos activation. c-Fos expression and activation induced by the exposure to recombinant IL-17C were markedly suppressed in the presence of the ERK inhibitor PD98059. These results suggest a possible positive feedback between c-Fos and IL-17C after C. pneumoniae infection. Taken together, our results indicate that C. pneumoniae infection promotes VSMC migration via c-Fos/IL-17C signaling.

IL-17c is involved in olfactory mucosa responses to Poly(I:C) mimicking virus presence.

At the interface of the environment and the nervous system, the olfactory mucosa (OM) is a privileged pathway for environmental toxicants and pathogens towards the central nervous system. The OM is known to produce antimicrobial and immunological components but the mechanisms of action of the immune system on the OM remain poorly explored. IL-17c is a potent mediator of respiratory epithelial innate immune responses, whose receptors are highly expressed in the OM of mice. We first characterized the presence of the IL-17c and its receptors in the OM. While IL-17c was weakly expressed in the control condition, it was strongly expressed in vivo after intranasal administration of polyinosinic-polycytidylic (Poly I:C), a Toll Like Receptor 3 agonist, mimicking a viral infection. Using calcium imaging and electrophysiological recordings, we found that IL-17c can effectively activate OM cells through the release of ATP. In the longer term, intranasal chronic instillations of IL-17c increased the cellular dynamics of the epithelium and promoted immune cells infiltrations. Finally, IL-17c decreased cell death induced by Poly(I:C) in an OM primary culture. The OM is thus a tissue highly responsive to immune mediators, proving its central role as a barrier against airway pathogens.

Interleukin-17C in Human Helicobacter pylori Gastritis.

The interleukin-17 (IL-17) family of cytokines (IL-17A to IL-17F) is involved in many inflammatory diseases. Although IL-17A is recognized as being involved in the pathophysiology of Helicobacter pylori-associated diseases, the role of other IL-17 cytokine family members remains unclear. Microarray analysis of IL-17 family cytokines was performed in H. pylori-infected and uninfected gastric biopsy specimens. IL-17C mRNA was upregulated approximately 4.5-fold in H. pylori-infected gastric biopsy specimens. This was confirmed by quantitative reverse transcriptase PCR in infected and uninfected gastric mucosa obtained from Bhutan and from the Dominican Republic. Immunohistochemical analysis showed that IL-17C expression in H. pylori-infected gastric biopsy specimens was predominantly localized to epithelial and chromogranin A-positive endocrine cells. IL-17C mRNA levels were also significantly greater among cagA-positive than cagA-negative H. pylori infections (P = 0.012). In vitro studies confirmed an increase in IL-17C mRNA and protein levels in cells infected with cagA-positive infections compared to cells infected with either cagA-negative or cag pathogenicity island (PAI) mutant. Chemical inhibition of IκB kinase (IKK), mitogen-activated protein extracellular signal-regulated kinase (MEK), and Jun N-terminal kinase (JNK) inhibited induction of IL-17C proteins in infected cells, whereas p38 inhibition had no effect on IL-17C protein secretion. In conclusion, H. pylori infection was associated with a significant increase in IL-17C expression in human gastric mucosa. The role of IL-17C in the pathogenesis of H. pylori-induced diseases remains to be determined.

Comparative study of interleukin-17C (IL-17C) and IL-17D in large yellow croaker Larimichthys crocea reveals their similar but differential functional activity.

Interleukin 17 (IL-17) family members are key players in regulating the immune response in mammals. Here, we identified the IL-17C and IL-17D homologs from large yellow croaker (Larimichthys crocea), named LcIL-17C and LcIL-17D, respectively. The deduced LcIL-17C and LcIL-17D proteins possessed the typical IL-17 domain and shared a conserved arrangement of eight cysteine residues. Both LcIL-17C and LcIL-17Dc genes were constitutively expressed in all tissues examined, although at different levels. After challenge with Aeromonas hydrophila, the expression of LcIL-17C and LcIL-17D was significantly increased in gills, head kidney, and spleen. In the peripheral blood leukocytes (PBLs), the recombinant LcIL-17C (rLcIL-17C) could strongly promote the expression of chemokines (CXCL8, CXCL12, and CXCL13), proinflammatory factors (TNF-α, IL-1ß, IL-6, and IFNg), and antibacterial peptide hepcidin, whereas rLcIL-17D induced a weaker expression of these chemokines. Consistently, the culture supernatants from the PBLs treated by rLcIL-17C showed a stronger ability to induce the migration of PBLs than those treated by rLcIL-17D. Furthermore, both rLcIL-17C and rLcIL-17D could activate the NF-κB signalling in the epithelioma papulosum cyprini (EPC) cells. Taken together, these results indicated that LcIL-17C and LcIL-17D, although differing in their ability to mediate chemotaxis for PBLs, may promote the inflammatory response and host defence via activating NF-κB signalling. To our knowledge, this is the first report on functional identification of a IL-17C in teleost.

IL-17C and its receptor IL-17RA/IL-17RE identify human oral epithelial cell as an inflammatory cell in recurrent aphthous ulcer.

BACKGROUND: Recurrent aphthous ulcer (RAU) is an ulcerative disease of non-keratinized oral mucosa. Colon and bronchial epithelial cells produce interleukin-17C (IL-17C) upon stimulation of Toll-like receptor 2 (TLR2), TLR3 and TLR5, which are highly expressed in epithelial cells in RAU lesions. We therefore investigated the eventual presence and function of IL-17C in cultured human oral keratinocytes (HOK) and control biopsies compared to RAU lesions. METHODS: Expression of IL-17A, IL-17C, IL-17RA and IL-17RE was analysed in cultured HOK cells using quantitative real-time polymerase chain reaction (qRT-PCR). HOK cells were stimulated with IL-17C and analysed for IL-8 and tumour necrosis factor-α (TNF-α) using qRT-PCR. Control mucosa (n = 5) was immunostained for IL-17A, IL-17C, IL-8, TNF-α and mast cell tryptase and compared with RAU lesions (n = 5) using the mean grey scale value. RESULTS: IL-17C, but no IL-17A, mRNA was found in cultured HOK cells. Components of the heterodimeric IL-17RA/IL-17RE receptor for IL-17C were also highly expressed. Stimulation of HOK with IL-17C increased TNF-α mRNA (P = 0.03; IL-8 increase was not statistically significant). HOK in RAU lesions stained intensively for IL-17C compared to controls (P = 0.006). This was associated with increased epithelial immunostaining of TNF-α (P = 0.04) and IL-8 (P = 0.02). Most of the inflammatory cells which stained for IL-17A in control mucosa and RAU lesions were also mast cell tryptase positive. CONCLUSION: IL-17C is highly expressed in epithelial cells in RAU lesions, where it seems to stimulate oral keratinocytes via IL-17RA/IL-17RE to produce pro-inflammatory cytokines. Human oral epithelial cells are probably important inflammatory cells in RAU.