Cytokines in colitis associated cancer: potential drug targets?

In inflammatory bowel disease (IBD), such as UC and CD, the development of colorectal carcinoma can be initiated through chronic inflammation, depending on the duration and severity of the disease. Growing evidence supports a role for various cytokines, released by epithelial and immune cells, in the pathogenesis of colitis associated cancer (CAC). For instance, TNF-alpha has been recently shown to promote tumor development in experimental colitis. Due to its role in the pathogenesis of IBD, TNF-alpha blockade has become one of the cornerstones of IBD therapy. Thus, anti-TNF-alpha strategies could also provide effective anti-tumor therapies. TGF-beta has been shown to attenuate an anti-tumor immune-response through the induction of regulatory T cells in spontaneous and inflammation associated cancer. However, IL-6 signaling promotes tumor growth in experimental CAC, and this signaling is inhibited by TGF-beta. Members of the IL-12 family, such as IL-12, IL-23, and IL-27, have been implicated in pathogenesis of colitis and IL-23 seems to be involved in inflammation associated carcinogenesis. However, a role for those cytokines in CAC remains to be shown. Whereas the above-mentioned cytokines promote tumor growth, others provide an anti tumor effect. IL-10 deficient mice develop colitis and CAC a few weeks after birth. Besides its immunosuppressive properties, IL-10 also has anti angiogenic and both tumor promoting and -inhibiting properties, which could be responsible for these observations. Since most of the above mentioned cytokines are involved in both, inflammation and carcinogenesis, it is difficult to account their contribution to the individual steps during pathogenesis of CAC. However, as already shown in IBD, cytokines may also provide promising therapeutic targets in CAC.     

Role and pharmacogenomics of TNF-alpha in asthma

Asthma is a chronic heterogeneous inflammatory disease of the respiratory system in which numerous cytokines play a significant role. Among them TNF-alpha (tumour necrosis factor alpha), a proinflammatory cytokine, has a predominant role in orchestrating airway inflammation and affecting treatment outcome. In this review we attempt to summarize the involvement of TNF-alpha in the pathogenesis of asthma, illustrate variations of TNF-alpha gene that potentially influence asthma phenotype and highlight promising therapies by blocking the production of TNF-alpha or inhibiting its action. A cytokine specific target therapy seems to be very promising since agents that block TNF-alpha slow disease progression, suppress inflammation and in some cases induce remission of chronic inflammation.     

TNF-alpha antagonists: monoclonal antibodies, soluble receptors, thalidomide and other novel approaches

Tumour necrosis factor-alpha (TNF-alpha) is a pleiotropic molecule produced in response to a variety of stimuli during normal host defence. At low levels, TNF-alpha confers protection against infectious agents, tumours and tissue damage, and plays a role in the development of humoral immunity. However, overproduction of TNF-alpha has been implicated in the pathogenesis of a wide variety of conditions, including autoimmunity, malignancy, inflammatory and immunopathological diseases. Furthermore, TNF-alpha is a key regulator of other pro-inflammatory cytokines; infiltrating mononuclear cells that produce excessive amounts of TNF-alpha at sites of inflammation are, therefore, primary targets for therapeutic intervention. Traditional anti-inflammatory drugs, such as cyclosporin, have widespread immunosuppressive effects and are now being replaced by more specific anti-TNF-alpha compounds. In this report, work presented at the recent Cambridge Symposia meeting on TNF-alpha antagonists in Santa Fe, New Mexico, will be highlighted and discussed.     

Molecular targets of rheumatoid arthritis

Rheumatoid arthritis (RA) is a multifactorial disease characterized by chronic inflammation of the joints. Both genetic and environmental factors are involved in the pathogenesis of joint destruction and disability. In the inflamed RA joint, the synovium is highly infiltrated by CD4+ T cells, B cells, and macrophages. Furthermore, the intimal lining becomes hyperplastic due to the increased numbers of macrophage-like and fibroblast-like synoviocytes. This hyperplastic intimal synovial lining forms an aggressive front, called pannus, which invades cartilage and bone structures, leading to compromised function and/or destruction of affected joints. RA pathology is mediated by a number of cytokines (TNF-alpha, IL-1, IL-6, IL-17, IFN gamma, etc.), chemokines (MCP-1, MCP-4, CCL18, etc.), cell adhesion molecules (ICAM-1, VCAM-1, etc.) and matrix metalloproteinases. Currently, treatment strategies targeted against TNF-alpha, IL-1 and IL-6 are available. In this review, we will summarize the use of biologics, the pros and cons of the use of biologics, and discuss on the potential molecular targets of RA.     

Serum cytokines and bioumoral immunological characterization of psoriatic patients in long term etanercept treatment

The purpose of this study is to evaluate blood cytokines and immunological parameters in psoriatic patients during long-term treatment with Etanercept. Forty-five subjects of both sexes affected by psoriasis with or without arthritis entered the study and were treated with Etanercept according to international standard protocols. Biochemical blood analysis was carried out at baseline and during follow-up every second month. In particular, the following parameters were kept under control: antinuclear antibodies, anti-nDNA antibodies, anti-histone antibodies, blood cell count, circulating lymphocyte subtypes (CD3, CD4, CD8, CD16, CD19) and IgE. Cytokine profiles (IL-1-alpha, IL-1-beta, IL-6, IL-8, IL-10, IL-12, INF, TNF-alpha) were also evaluated in blood samples during the treatment up to 1 year of follow-up. A significant decrease in PASI score (p < 0.01) and in several cytokine levels was observed, particularly in IL-1, IL-6, IFN-gamma (p < 0.01) and to a lesser extent in TNF-alpha (p < 0.05). No statistically significant changes were recorded after 1 year of follow-up in blood immunological parameters, in particular in ANA titre, CD4/CD8 ratio, IgE levels, CD16, CD19 and eosinophils count. In conclusion, long-term treatment with Etanercept leads not only to a significant improvement in PASI score, but also to significant changes (reduction) in several proinflammatory and modulatory cytokines involved in the pathogenesis of the disease; on the other hand, there are no effects on immunological or bioumoral parameters showing that etanercept modulates rather than suppresses the physiological responses during psoriasis treatment.     

Role of tumor necrosis factor in Crohn's disease

Tumor necrosis factor-alpha (TNF alpha) is one of several pro-inflammatory cytokines that have been implicated in the pathogenesis of Crohn's disease (CD). Treatment with antibodies to TNF alpha has been shown to reduce mucosal inflammation in the disease, promote tissue healing, achieve and maintain remission, improve the CD activity index (CDAI) and improve the quality of life. The first part of this article reviews the role of TNF alpha in CD.     

Anti-interleukin-6 therapy for Crohn's disease

Proinflammatory cytokines have been demonstrated to play a crucial role in the pathogenesis and physiopathology of various chronic inflammatory conditions including Crohn's disease (CD). Among these cytokines, interleukin-6 (IL-6) must be especially important because increased serum concentrations of acute phase proteins, reduced level of serum albumin, and remarkable thrombocytosis are all well-explained by the increased level of IL-6. Moreover, IL-6 is capable of stimulating even IL-6 receptor (IL-6R) negative cells such as vascular endothelial cells when complexed to soluble form of IL-6R (sIL-6R), and serum level of IL-6 as well as sIL-6R has been demonstrated to increase during inflammation. To investigate the therapeutic potential of IL-6 signaling blockade for CD, anti-IL-6R monoclonal antibody (mAb) was introduced to various murine models of colitis. Anti-IL-6R mAb successfully prevented wasting disease and the development of macroscopic and histological lesions. It suppressed the accumulation of ICAM-1 positive and Mac-1 positive cells in the lamina propria (LP) and the expression of ICAM-1 and VCAM-1 by vascular endothelial cells. Expansion of colonic and splenic CD4(+) T cells was reduced as well as the colonic expression of tumor necrosis factor alpha (TNF-alpha), IL-1beta, and interferon gamma (IFN-gamma) mRNA without affecting the production of transforming growth factor beta (TGF-beta), IL-10, and IL-4 mRNA. The treatment also suppressed established colitis by inducing LP T cell apoptosis. These results strongly suggest that specific targeting of IL-6/sIL-6R pathway will be a promising new approach for the treatment of CD, and the clinical trial of humanized anti-IL-6R mAb is now under way.     

Endotoxin induces late increase in the production of pulmonary proinflammatory cytokines in murine lupus-like pristane-primed modelp

Lupus-like syndrome is characterized by multiple organ injuries including lungs and kidneys. Endotoxin induces a transiently intent systemic inflammatory response and indirectly transient acute lung injury in normal condition. However, whether endotoxin may trigger the persistent development of lung injury in chronic, inflammatory lupus-like syndrome compared with normal condition remains unclear. We examined the pulmonary vascular permeability and production of proinflammatory cytokines, such as TNF-alpha, IL-6, IL-10 and IFN-gamma, which play prominent roles in the pathogenesis of lupus-like tissue injury, 6 h and 72 h after i.p. lipopolysaccharide (LPS; endotoxin) injection in pristane-primed chronic inflammation ICR mice characterized by a lupus-like syndrome. These results demonstrated that levels of serum IL-6, IL-10 and IFN-gamma and bronchoalveolar lavage (BAL) IL-6 and IFN-gamma were remarkably increased 6 h in LPS-exposed pristane-primed mice compared with pristane-primed controls, while pulmonary vascular permeability and levels of serum and BAL TNF-alpha were not. And levels of BAL TNF-alpha, IL-6 and IL-10 were significantly enhanced 72 h in LPS-exposed pristane-primed mice compared with pristane-primed controls. Also, LPS significantly induced the increased in vitro production of TNF-alpha, IL-6 and IL-10 by lung cells obtained from LPS-exposed pristane-primed mice compared with LPS-exposed normal mice. Our findings indicate that LPS may trigger persistent progression of lung injury through late overproduction of BAL TNF-alpha, IL-6, and IL-10 in lupus-like chronic inflammation syndrome compared with normal condition.     

Allergic inflammation: role of cytokines with special emphasis on IL-4

This review examines recent articles on the relationship of cytokines to allergy and inflammation with particular emphasis on interleukin (IL)-4. The objective of this article is therefore to review published studies to identify cytokines consistently involved in allergic inflammation. Proinflammatory cytokines, including IL-4, IL-5, IL-13 and GM-CSF along with TNF-alpha play a role in allergen-induced airway leukocyte recruitment and these cytokines can be generated by T mast cells and other cells. In addition, IL-9, IL-25, IL-33, IL-17, IL-27 and IFN-gamma are deeply involved in the regulation of asthma. Blocking the effect of these proinflammatory cytokines might provide new therapeutic approaches for the control of allergy and inflammation.     

Lipopolysaccharide-induced lung inflammation is inhibited by neutralization of GM-CSF

Granulocyte-macrophage colony-stimulating factor (GM-CSF) plays an important role in the pathogenesis of acute and chronic lung disease as a major regulator governing the functions of granulocyte and macrophage lineage populations. Chronic obstructive pulmonary disease (COPD) is a disease characterized by lung inflammation with accumulation of neutrophils and increased levels of pro-inflammatory cytokines including GM-CSF in the patient's lungs. We used intranasal administration of lipopolysaccharide (LPS) to mice to induce a disease that resembles COPD with pulmonary inflammation, neutrophil recruitment and release of pro-inflammatory mediators in the bronchoalveolar lavage fluid of the diseased mice. 2 h prior to LPS administration, mice were systemically treated with the murine GM-CSF neutralizing antibody mAb 22E9 per intraperitoneal injection. Intranasal challenge with LPS-induced an increase of total cell number and of neutrophils in the bronchoalveolar lavage fluid. Elevated levels of tumor necrosis factor alpha (TNF-alpha), keratinocyte cytokine and macrophage inflammatory protein-2 (MIP-2) were also observed at this time point. GM-CSF was no longer detectable in bronchoalveolar lavage fluid at 24 h due to its early expression with a peak reached 6 h after LPS challenge. Pretreatment of mice with GM-CSF neutralizing antibody dose-dependently inhibited the accumulation of neutrophils and reduced TNF-alpha and MIP-2 protein levels in bronchoalveolar lavage fluid. These data suggest that neutralization of GM-CSF may represent a novel treatment modality for lung inflammation and in particular for COPD.     

Increased tumor necrosis factor-alpha production by peripheral blood leukocytes from TCDD-exposed rhesus monkeys.

Previous work has shown that exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is associated with a dose-dependent increase in the incidence and severity of endometriosis in the rhesus monkey. Studies also suggest that immune mechanisms participate in TCDD-mediated toxicity and the pathogenesis of endometriosis. Thirteen years after TCDD treatment was terminated, we characterized the phenotypic distribution of peripheral blood mononuclear cells (PBMC) from TCDD-exposed and -unexposed rhesus monkeys and determined the ability of these cells to produce cytokines and exert cytolytic activity against NK and T-cell-sensitive cell lines. We also determined whether elevated serum levels of TCDD, dioxin-like PHAH congeners, and triglycerides correlated with changes in PBMC phenotype or function. For all animals, TCDD exposure correlated with increased PBMC tumor necrosis factor-alpha (TNF-alpha) secretion in response to stimulation by T-cell mitogen and decreased cytolytic activity against NK-sensitive target cells. Furthermore, increased production of this cytokine by PHA-stimulated leukocytes was associated with elevated serum triglyceride levels. Leukocyte TNF-alpha secretion in response to viral antigen and PBMC production of interferon gamma (IFNgamma), IL-6, and IL-10 following exposure to mitogen or antigen were unaffected by previous TCDD treatment. Although TCDD exposure was not associated with changes in PBMC surface antigen expression, elevated serum concentrations of TCDD, 1,2,3,6,7,8-hexachlorodibenzofuran and 3,3',4,4',5-pentachlorobiphenyl correlated with increased numbers of CD3+/CD25- and CD3-/CD25+ leukocytes and enhanced secretion of TNF-alpha by mitogen-stimulated PBMC. These findings indicate that TCDD-exposed rhesus monkeys with endometriosis exhibit long-term alterations in systemic immunity associated with elevated serum levels of specific PHAH congeners.     

Treatment of Crohn's disease with infliximab.

The role of infliximab in managing Crohn's disease (CD) is described. CD is characterized by chronic transmural inflammation at various sites of the gastrointestinal tract, particularly the ileum and colon. The major symptoms are diarrhea, abdominal pain, enterocutaneous and perianal fistulas, and weight loss. Management goals include alleviating symptoms, inducing remission, promoting healing of the intestinal mucosa and fistulas, and modifying the disease process. Drugs traditionally used to manage CD are aminosalicylates, antimicrobials, immunomodulatory agents, and corticosteroids. Infliximab is a chimeric (human-mouse) monoclonal antibody targeted at human tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine important in the pathogenesis of CD. Infliximab antagonizes the biological activity of TNF-alpha by binding to it on macrophage and T-cell surfaces. Clinical trials have shown infliximab to be effective in producing and maintaining a clinical response in patients with refractory, moderate to severe CD. Treatment helps promote healing of intestinal mucosa and closure of fistulas. Infliximab may act more rapidly than most traditional agents and produces less severe adverse effects. The most frequent adverse effects are headache, nausea, and upper-respiratory-tract infections. The recommended dosage is 5 mg/kg i.v. infused over a two-hour period. Infliximab may be given at eight-week intervals for maintenance or management of flare-ups. Infliximab appears useful in the treatment of CD and may improve patients' quality of life.     

The role of Wolbachia bacteria in the pathogenesis of onchocerciasis and prospects for control of the disease

Onchocerciasis, a non-fatal disease, is a major public health problem especially in sub-Saharan Africa causing disfigurement, severe itching, skin depigmentation, vision impairment and eventually blindness. The discovery of Wolbachia intracellular bacteria in the filarial nematodes has contributed a lot to the understanding of host's immune response to the bacteria and its role in the pathogenesis of onchocericiasis. Lipopolysaccharide molecules (LPS) associated with the bacteria are responsible for the induction of potent inflammatory responses mainly mediated by macrophages. LPS binding to CD14 on the monocytes/macrophages which is a co-receptor for Toll like receptor (TLR), induces the activation of an intracellular signaling that leads to the production of proinflammatory cytokines such as TNF-alpha, IL-1, IL-12 by macrophages. The cytokines initiate the recruitment of neturophils and macrophages to the vicinity of the adult worms/microfilaria especially to the cornea, which gradually causes corneal pathology. Therefore studies have suggested that Wolbachia plays an essential role in the induction of inflammatory response associated with the pathogenesis of onchocericiasis through the activation of innate immune response. Hence the aim of this study is to show the role wolbachia plays in the pathogenesis of this devastating illness and target for novel chemotherapy.     

T cells are involved in the development of arthritis induced by anti-type II collagen antibody

T cells play an important role in initiating autoimmune responses and maintaining synovial inflammation in rheumatoid arthritis. Although, anti-type II collagen antibody-induced arthritis (CAIA) is generally believed to be a T cell- and B cell-independent model, the detailed pathogenesis of CAIA remains unclear. In the present study, to elucidate the contribution of T cells to the pathogenesis of CAIA, we evaluated the effects of CTLA4 Ig and cyclosporin (CsA). Arthritis was induced in mice by intravenous injection of anti-type II collagen antibody followed by intraperitoneal injection of lipopolysaccharide. CTLA4 Ig was intraperitoneally administered and CsA was subcutaneously administered; then the severity of arthritis was evaluated by scoring the edema and erythema of paws and by measuring hind paw thickness. Paw samples were collected 12 days after the antibody injection, and the mRNA expression levels were analyzed by real-time quantitative polymerase chain reaction. Administration of CTLA4 Ig ameliorated the increases in arthritic score and paw thickness in the later phase, but not in the early phase of arthritis. CsA suppressed the increases in arthritic score and paw thickness in both the early and later phases of arthritis. CTLA4 Ig and CsA suppressed mRNA up-regulation of T-cell markers, CD3 and CD25, and immune response-related mediators, IFN-gamma and IL-12. They also suppressed the up-regulation of macrophage marker, F4/80, and proinflammatory cytokines, TNF-alpha, IL-1beta and IL-6. The results provide direct evidence that arthritis in this model is T-cell activation dependent.     

Role of cytokines in neurological disorders

The balance between cytokines with pro- and anti-inflammatory effects contributes to the course of the Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy. TNFalpha seems to be an important factor in the cascade of events leading to demyelination and even axonal damage. During the acute phase, the serum concentrations of TNFalpha and IL-6 are elevated while anti-inflammatory cytokines are up-regulated in the recovery phase. Cytokines also have a key role in the pathogenesis of multiple sclerosis and most data suggest that this effect is mediated by myelin-specific CD4 T lymphocytes secreting Th type 1 cytokines. However, several different immune cells including B lymphocytes, CD8 T lymphocytes and NK T lymphocytes are also involved in the pathogenesis. Both Th1 and Th2 lymphocytes and cytokines probably participate in the development of myasthenia gravis (MG). The IFNalpha production is probably related to the severity of the disease, with clinical improvement associated with decreased production. The serum levels of IL-18 are significantly elevated in MG, with highest concentrations in patients with generalized disease. The immune system may be involved in the pathogenesis of AD by the effect of microglia, which can induce microglial activation with subsequent release of pro-inflammatory cytokines. In parkinsonism, there is evidence of chronic inflammation in the substantia nigra and striatum. Activated microglia, producing proinflammatory cytokines, surround the degenerating dopaminergic neurons and may contribute to the dopaminergic neuron loss. Studies of patients with epilepsy and animals with experimentally induced seizures indicate that cytokines may also influence the electrophysiological properties of neurons.     

Re-evaluation of fibrogenic cytokines in lung fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a chronic interstitial lung disease which results in end-stage fibrosis. The pathogenesis is believed to be related to a dysregulation in cross-talk between inflammatory and structural cells, mediated by various cytokines, chemokines and growth factors, which are responsible for the maintenance of tissue homeostasis and which coordinate the response to injury. The large number of mediators involved and the complexity of their interaction makes it difficult to identify the factors responsible for initiation of fibrogenesis and progression to chronicity. Whether a mediator's presence in fibrotic lung is as a result of tissue injury or if it playsan active role in disease onset and progression has been partly answered by the use of transient and/or permanent transgenic and gene knock-out approaches to over-express single factors at a time. Chemokines such as interleukin-8 (IL-8), RANTES, IP-10, MIG or lymphotactin, do not appear to induce fibrosis when over-expressed in rodent lung. Amongst many tested, four cytokines and growth factors have been found to be pro-fibrotic; IL-1beta, which demonstrates marked inflammation, tissue damage and chronic fibrosis, TNF-alpha, which induces inflammation and mild fibrosis, and GM-CSF, which induces moderate inflammation and fibrosis. A common finding with these cytokines are increased lung TGF-beta levels, proportionate to the degree of fibrosis generated, while TGF-beta itself causes minor inflammation but marked progressive chronic fibrosis. A growth factor 'downstream' from the pro-fibrotic effects of TGF-beta, CTGF, is a likely critical mediator. However, over-expression of CTGF produces only mild and reversible fibrosis.     

Potential biomarker of coal workers' pneumoconiosis.

It is well known that various cytokines and growth factors secreted from macrophages/monocytes play the key role in the pathogenesis of pneumoconiosis. These can act as biosensors for the prediction of pneumoconiosis. To evaluate which cytokines can be used as sensitive biomarkers in pneumoconiosis, we measured tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8) and platelet-derived growth factor-AA (PDGF-AA) in supernatant of monocytes with or without coal dust (5 mg/ml) and serum in 42 coal miners with pneumoconiosis and ten healthy control. The coal-stimulated release of TNF-alpha and IL-8 from blood monocytes was significant increased in pneumoconiosis patients compared with controls. The level of TNF-alpha and IL-8 in blood serum was higher in subjects with pneumoconiosis than in controls.     

Role of TNF-alpha and extracellular ATP in THP-1 cell activation following allergen exposure

Dendritic cells (DCs), including Langerhans cells (LCs), play a critical role in the induction phase of allergic contact hypersensitivity. Following exposure to chemical allergens in the skin, LCs undergo a maturation process leading to the up-regulation of expression of co-stimulatory molecules, such as CD86, CD54 and CD40. Our previous study revealed that chemical allergens induce phenotype alterations (e.g., CD86, CD54 and CD40) and cytokine production (TNF-alpha and IL-8) in THP-1 cells that possibly reflect the maturation of dendritic cells during skin sensitization. However, the physiological signals for phenotypic alterations by chemical allergens are still not fully understood. Therefore, in this study, we investigated the effect of TNF-alpha and extracellular ATP on THP-1 cell activation induced by chemical allergens. Kinetic studies revealed that TNF-alpha and IL-8 release occurred in a time-dependent manner with release of two cytokines beginning at 3 hr post-exposure to well-known haptens, DNCB and NiSO(4). While recombinant human TNF-alpha augmented CD54 and CD40 expression in a dose-dependent manner, rhTNF-alpha did not increase CD86 expression. Furthermore, neutralization of TNF-alpha activity strongly inhibited CD54 and CD40 expression induced by allergens. On the contrary, extracellular ATP induced the up-regulation of both CD86 and CD54 expression. In the presence of the P2 receptor antagonist suramin, the up-regulation of CD86 and CD54 expression by allergens was in part suppressed. Therefore, we postulate that not only TNF-alpha but also extracellular ATP may contribute to cell activation following allergen stimulation, which might reflect the mechanism by which DCs respond to allergens.     

Bruton’s tyrosine kinase inhibitor suppresses imiquimod-induced psoriasis-like inflammation in mice through regulation of IL-23/IL-17A in innate immune cells

Psoriasis is an unchecked chronic inflammation characterized by thick, erythematous, and scaly plaques on the skin. The role of innate immune cells in the pathogenesis of psoriasis is well documented. Bruton’s tyrosine kinase (BTK) has been reported to execute important signaling functions in innate immune cells such as dendritic cells (DCs) and gamma delta T cells. However, whether inhibition of BTK would lead to modulation of innate immune function in the context of psoriatic inflammation remains largely unexplored. In the present study, we investigated the effect of selective BTK inhibitor, PCI-32765 on inflammatory signaling in CD11c + DCs and gamma delta T cells in imiquimod (IMQ)-induced mouse model of psoriasis-like inflammation. Our results show that IMQ treatment led to induction of p-BTK expression along with concomitant increase in inflammatory cytokines (IL-23, TNF-α) in CD11c + DCs in the skin. Preventive treatment with BTK inhibitor led to significant reversal in IMQ-induced inflammatory changes in CD11c + DCs of skin. Further, there was a significant decrease in dermal IL-17A levels and IL-17A + γδ + T cells after treatment with BTK inhibitor. Furthermore, short treatment of back skin with IMQ led to upregulated expression of p-BTK along with inflammatory cytokines in CD11c + DCs (IL-23, TNF-α) and IL-17A in γδ + T cells which were reversed by BTK inhibitor. Overall, our study proposes that BTK signaling serves a crucial signaling function in innate immune cells in the context of psoriatic inflammation in mice. Therefore, BTK might be a promising therapeutic target to treat psoriatic inflammation.