Inhibition of the signalling kinase JAK3 alleviates inflammation in monoarthritic rats

Identification of potential immunomodulators from Pulsatilla decoction that act on therapeutic targets for ulcerative colitis based on pharmacological activity, absorbed ingredients, and in-silico molecular docking

BACKGROUND

Pulsatilla decoction (Bai-Tou-Weng-Tang, BTWT) is a classic formula prescription of a traditional Chinese medicine that is used to treat ulcerative colitis (UC). However, its active components and underlying mechanism of action remain unclear. In the present study, we aimed to identify potential immunomodulators from BTWT that act at therapeutic targets for UC.

METHODS

The protective effects of BTWT granules were examined in mice with colitis induced by dextran sulfate sodium. The absorbed components of BTWT were identified using LC-MS, and selected protein targets of these components in UC were investigated using molecular docking.

RESULTS

Oral administration of BTWT granules significantly alleviated disease severity and colon shortening, and inhibited the inflammatory response in mice with chronic colitis. In these mice, 11 compounds from the BTWT granules were detected in the serum and/or colon. The molecular docking study demonstrated that compounds from Radix pulsatillae, such as anemoside A3, interacted with STAT3 and S1PR1; compounds from Rhizoma coptidis and/or Cortex phellodendri, such as palmatine, interacted with JAK3, PD-1, and PD-L1; and components of Cortex fraxini such as aesculin interacted with S1PR1, JAK3, STAT3 and PD-L1. Further in-vitro experiments showing that the compounds inhibited TNF-α and IL-6 production and STAT3 activation in RAW 264.7 cells suggested that these compounds have immunomodulatory activities.

CONCLUSION

We revealed for the first time that 11 absorbed ingredients from BTWT were immunomodulators against therapeutic targets for UC. These findings suggest that the identified compounds are the active components of BTWT, and the identified protein targets underlie the mechanism of action of BTWT against UC.

Transcriptome-Wide High-Throughput m6A Sequencing of Differential m6A Methylation Patterns in the Human Rheumatoid Arthritis Fibroblast-Like Synoviocytes Cell Line MH7A

Introduction

N6-methyladenosine (m6A) is the most frequent internal modification in eukaryotic mRNAs and is closely related to the occurrence and development of many diseases, especially tumors. However, the relationship between m6A methylation and rheumatoid arthritis (RA) is still a mystery.

Methods

Two high-throughput sequencing methods, namely, m6A modified RNA immunoprecipitation sequence (m6A-seq) and RNA sequence (RNA-seq) were performed to identify the differentially expressed m6A methylation in human rheumatoid arthritis fibroblast-like synoviocytes cell line MH7A after stimulation with TNF-α. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to obtain enriched GO terms and significant KEGG pathways. Then, four candidate genes, Wilms tumor 1-associating protein (WTAP), receptor-interacting serine/threonine protein kinase 2 (RIPK2), Janus kinase 3 (JAK3) and tumor necrosis factor receptor SF10A (TNFRSF10A) were selected to further validate the m6A methylation, mRNA and protein expression levels in MH7A cells and synovial tissues of adjuvant arthritis (AA) rats by RT-qPCR and Western blot.

Results

Using m6A-seq, we identified a total of 206 genes with differentially expressed m6A methylation, of which 118 were significantly upregulated and 88 genes were significantly downregulated. Likewise, 1207 differentially mRNA expressed mRNAs were obtained by RNA-seq, of which 793 were upregulated and 414 downregulated. Further joint analysis showed that the m6A methylation and mRNA expression levels of 88 genes changed significantly, of which 30 genes displayed increased m6A methylation and decreased mRNA expression, 57 genes displayed decreased m6A methylation and increased mRNA expression increased, and 1 gene displayed increased m6A methylation and increased mRNA expression. GO and KEGG analyses indicated that these unique genes were mainly enriched in inflammation-related pathways, cell proliferation and apoptosis. In addition, the validations of WTAP, RIPK2, JAK3 and TNFRSF10A were in accordance with the m6A and RNA sequencing results.

Conclusion

This study established the transcriptional map of m6A in MH7A cells and revealed the potential relationship between RNA methylation modification and RA related genes. The results suggested that m6A modification was associated with the occurrence and course of RA to some extent.

Anticancer activities of TCM and their active components against tumor metastasis

Traditional Chinese Medicine (TCM) has the characteristics of multiple targets, slight side effects and good therapeutic effects. Good anti-tumor effects are shown by Traditional Chinese Medicine prescription, Chinese patent medicine, single Traditional Chinese Medicine and Traditional Chinese medicine monomer compound. Clinically, TCM prolonged the survival time of patients and improved the life quality of patients, due to less side effects. Cancer metastasis is a complex process involving numerous steps, multiple genes and their products. During the process of tumor metastasis, firstly, cancer cell increases its proliferative capacity by reducing autophagy and apoptosis, and then the cancer cell capacity is stimulated by increasing the ability of tumors to absorb nutrients from the outside through angiogenesis. Both of the two steps can increase tumor migration and invasion. Finally, the purpose of tumor metastasis is achieved. By inhibiting autophagy and apoptosis of tumor cells, angiogenesis and EMT outside the tumor can inhibit the invasion and migration of cancer, and consequently achieve the purpose of inhibiting tumor metastasis. This review explores the research achievements of Traditional Chinese Medicine on breast cancer, lung cancer, hepatic carcinoma, colorectal cancer, gastric cancer and other cancer metastasis in the past five years, summarizes the development direction of TCM on cancer metastasis research in the past five years and makes a prospect for the future.

A peptide derived from the core β-sheet region of TIRAP decoys TLR4 and reduces inflammatory and autoimmune symptoms in murine models

BACKGROUND

TLRs are some of the actively pursued drug-targets in immune disorders. Owing to a recent surge in the cognizance of TLR structural biology and signalling pathways, numerous therapeutic modulators, ranging from low-molecular-weight organic compounds to polypeptides and nucleic acid agents have been developed.

METHODS

A penetratin-conjugated small peptide (TIP3), derived from the core β-sheet of TIRAP, was evaluated in vitro by monitoring the TLR-mediated cytokine induction and quantifying the protein expression using western blot. The therapeutic potential of TIP3 was further evaluated in TLR-dependent in vivo disease models.

FINDINGS

TIP3 blocks the TLR4-mediated cytokine production through both the MyD88- and TRIF-dependent pathways. A similar inhibitory-effect was exhibited for TLR3 but not on other TLRs. A profound therapeutic effect was observed in vivo, where TIP3 successfully alleviated the inflammatory response in mice model of collagen-induced arthritis and ameliorated the disease symptoms in psoriasis and SLE models.

INTERPRETATION

Our data suggest that TIP3 may be a potential lead candidate for the development of effective therapeutics against TLR-mediated autoimmune disorders.

FUNDING

This work was supported by the National Research Foundation of Korea (NRF-2019M3A9A8065098, 2019M3D1A1078940 and 2019R1A6A1A11051471). The funders did not have any role in the design of the present study, data collection, data analysis, interpretation, or the writing of the manuscript.

Berberine Inhibits Pro-inflammatory Cytokine-induced IL-6 and CCL11 Production via Modulation of STAT6 Pathway in Human Bronchial Epithelial Cells

Berberine is an isoquinoline alkaloid isolated from various Chinese herbs that has potential of anti-inflammatory, anti-lipidemic, anti-neoplastic, and anti-diabetic activity. In this study, we evaluated the anti-inflammatory efficacy of berberine on allergic airway inflammation by targeting epithelial cells. Allergic airway inflammation driven by T helper 2 (Th2)-type immunity is characterized by airway hyperresponsiveness, elevated IgE production, and eosinophilic infiltration. For eosinophil recruitment, major chemoattractant CCL11 (eotaxin-1) was secreted by lung epithelial cells. BEAS-2B cells, a human bronchial epithelial cell line, were pre-treated with berberine and then activated by IL-4 plus TNF-α. The viability of BEAS-2B cells was assessed. Expression levels of IL-6 and CCL11 were determined using ELISA and real-time PCR. The signaling pathways of MAP kinases, NF-κB, and STAT6 were analyzed by western blot. Berberine treatment (≤1 μM) didn't significantly affect the viability of BEAS-2B cells with or without IL-4 plus TNF-stimulation. Berberine significantly inhibited the secretion of IL-6 and CCL11 from pro-inflammatory cytokine-activated BEAS-2B cells. NF-κB and MAP kinase pathways were seemingly unaffected in BEAS-2B cells with berberine treatment. Significant reduction of nuclear STAT6 protein expression in activated BEAS-2B cells with berberine treatment was observed. Current study reveals that berberine has inhibitory effect in pro-inflammatory cytokine-activated BEAS-2B cells through reducing IL-6 and CCL11 production, which is possibly modulated by suppressing STAT6 signaling pathway.

A Phase I Trial of Berberine in Chinese with Ulcerative Colitis

The Chinese natural product, berberine, has biological properties that support its potential efficacy as a colon cancer prevention agent. Its longstanding use in China to treat gastrointestinal tract and rheumatologic disorders is generally regarded as safe, supporting initial investigations in an at-risk population, such as individuals with ulcerative colitis. However, the safety of berberine in this population is not established. Individuals living in China with biopsy-proven ulcerative colitis, ≤grade 2 dysplasia, and with a ulcerative colitis disease activity index (UCDAI) score ≤1 on mesalamine, were randomized 3:1 in a double-blind phase I trial to berberine 900 mg/day or placebo for 3 months, with the primary objective of assessing safety. Blood samples and biopsies of the colorectum, from prespecified locations, were collected prior to and following therapy. Secondary endpoints included changes in UCDAI score, and in tissue and plasma markers of inflammation. Of toxicities at least possibly related, one episode of grade 3 elevation in transaminases and one episode of grade 1 nausea were observed among 12 individuals on berberine, and none were observed among 4 on placebo. The mean plasma berberine concentration was 3.5 nmol/L after berberine treatment, significantly higher than 0.5 nmol/L with placebo. Berberine significantly decreased the Geboes grade in colonic tissue, but had a nonsignificant effect on other tissue or blood biomarkers related to cell growth and inflammation. The combination of berberine and mesalamine is well tolerated in Chinese with ulcerative colitis and may enhance mesalamine's anti-inflammatory effects in colonic tissue.

A cell-penetrating peptide blocks Toll-like receptor-mediated downstream signaling and ameliorates autoimmune and inflammatory diseases in mice

Toll-like receptors (TLRs) recognize pathogen/damage-associated molecular patterns and initiate inflammatory signaling cascades. Occasionally, overexpression of TLRs leads to the onset of numerous inflammatory diseases, necessitating the development of selective inhibitors to allow a protective yet balanced immune response. Here, we demonstrate that a novel peptide (TIP1) derived from Toll/interleukin-1 receptor (TIR) domain-containing adapter protein inhibited multiple TLR signaling pathways (MyD88-dependent and MyD88-independent) in murine and human cell lines. TIP1 also inhibited NLRP3-mediated IL-1β secretion, as we validated at both the protein and mRNA levels. Biophysical experiments confirmed that TIP1 specifically binds to the BB loop of the TLR4-TIR domain. Animal studies revealed that TIP1 inhibited the secretion of lipopolysaccharide (LPS)-induced proinflammatory cytokines in collagen-induced arthritis (CIA) and kaolin/carrageenan-induced arthritis (K/C) rodent models. TIP1 also rescued animals from sepsis and from LPS-induced kidney/liver damage. Importantly, TIP1 ameliorated the symptoms of rheumatoid arthritis in CIA and K/C rodent models, suggesting that TIP1 has therapeutic potential for the treatment of TLR-mediated autoimmune/inflammatory diseases.

Anthocyanins and their gut metabolites attenuate monocyte adhesion and transendothelial migration through nutrigenomic mechanisms regulating endothelial cell permeability

Cardioprotective effects of dietary anthocyanins are partly attributed to their ability to maintain endothelial function. However, the underlying cellular and molecular mechanisms of action are not fully understood. This study aimed to evaluate the effect of anthocyanins and their gut metabolites, at physiologically-relevant conditions, on endothelial cell (EC) function and decipher the underlying molecular mechanisms of action using integrated omics approaches. Primary EC were treated with a mixture of 0.1 μM cyanidin-3-arabinoside, 0.1 μM cyanidin-3-galactoside, 0.1 μM cyanidin-3-glucoside, 0.1 μM delphinidin-3-glucoside, 0.1 μM peonidin-3-glucoside and 0.5 μM 4-hydroxybenzaldehyde for 3 h or a mixture of gut metabolites: 0.2 μM protocatechuic, 2 μM vanillic, 1 μM ferulic and 2 μM hippuric acids for 18 h. Also, successive exposure of EC to both mixtures was performed to mimic anthocyanin pharmacokinetics following their intake. Inflammatory stress was induced using TNFα and monocytes added to assess adhesion and transmigration. Effects of these mixtures on gene, miRNA expression and their potential interaction with cell signalling were investigated. Anthocyanins and their gut metabolites significantly reduced monocyte adhesion and transendothelial migration. Gene expression analysis, using macroarrays, showed that tested compounds modulated the expression of genes involved in cell-cell adhesion, cytoskeleton organisation or focal adhesion. Bioinformatics analyses of gene expression data identified potential transcription factors involved in the observed nutrigenomic effects and signalling proteins regulating their activity. Molecular docking revealed cell signalling proteins to which these bioactives may bind to and potentially affect their activity and the activation of downstream signalling, effects that were in agreement with the results of Western blot analyses. Microarray analysis showed that anthocyanins and their gut metabolites affected miRNA expression in EC, especially those involved in regulation of EC permeability, contributing to the observed changes in EC function. Integration of these results revealed endothelial-protective properties of anthocyanins and their gut metabolites and deciphered new underlying multi-target and multi-layered mode of action.

Berberine-induced Inactivation of Signal Transducer and Activator of Transcription 5 Signaling Promotes Male-specific Expression of a Bile Acid Uptake Transporter

Sodium-taurocholate co-transporting polypeptide (Ntcp/NTCP) is the major uptake transporter of bile salts in mouse and human livers. In certain diseases, including endotoxemia, cholestasis, diabetes, and hepatocarcinoma, Ntcp/NTCP expression is markedly reduced, which interferes with enterohepatic circulation of bile salts, impairing the absorption of lipophilic compounds. Therefore, normal Ntcp/NTCP expression in the liver is physiologically important. Berberine is an herbal medicine used historically to improve liver function and has recently been shown to repress STAT signaling. However, berberine effects on Ntcp/NTCP expression are unknown, prompting use to investigate this possible connection. Our results showed that berberine dose-dependently increased Ntcp expression in male mouse liver and decreased taurocholic acid levels in serum but increased them in the liver. In mouse and human hepatoma cells, berberine induced Ntcp/NTCP mRNA and protein expression and increased cellular uptake of [3H] taurocholate. Mechanistically, berberine decreased nuclear protein levels of phospho-JAK2 and phospho-STAT5, thus disrupting the JAK2-STAT5 signaling. Moreover, berberine stimulated luciferase reporter expression from the mouse Ntcp promoter when one putative STAT5 response element (RE) (-1137 bp) was deleted and from the human NTCP promoter when three putative STAT5REs (-2898, -2164, and -691 bp) were deleted. Chromatin immunoprecipitation demonstrated that berberine decreased binding of phospho-STAT5 protein to the-2164 and -691 bp STAT5REs in the human NTCP promoter. In summary, berberine-disrupted STAT5 signaling promoted mouse and human Ntcp/NTCP expression, resulting in enhanced bile acid uptake. Therefore, berberine may be a therapeutic candidate compound for maintaining bile acid homeostasis.

San-Huang-Xie-Xin-Tang Constituents Exert Drug-Drug Interaction of Mutual Reinforcement at Both Pharmacodynamics and Pharmacokinetic Level: A Review

Inflammatory disorders underlie varieties of human diseases. San-Huang-Xie-xin-Tang (SHXXT), composed with Rhizoma Rhei (Rheum palmatum L.), Rhizoma Coptidis (Coptis chinensis Franch), and Radix Scutellaria (Scutellaria baicalensis Georgi), is a famous formula which has been widely used in the fight against inflammatory abnormalities. Mutual reinforcement is one of the basic theories of traditional Chinese medicine. Here this article reviewed and analyzed the recent research on (1) How the main constituents of SHXXT impact on inflammation-associated signaling pathway molecules. (2) The interaction between the main constituents and efflux pumps or intestinal transporters. The goal of this work was to, (1) Provide evidence to support the theory of mutual reinforcement. (2) Clarify the key targets of SHXXT and suggest which targets need further investigation. (3) Give advice for the clinical use of SHXXT to elevated the absorption of main constituents and eventually promote oral bioavailability. We search literatures in scientific databases with key words of “each main SHXXT constituent,” in combination with “each main inflammatory pathway target molecule” or each main intestinal transporter, respectively. We report the effect of five main constituents on target molecules which lies in three main inflammatory signaling pathways, we as well investigate the interaction between constituents and intestinal transporter. We conclude, (1) The synergistic effect of constituents at both levels confirm the mutual reinforcement theory of TCM as it is proven in this work. (2) The effect of main constituents on downstream targets in nuclear need more further investigation. (3) Drug elevating the absorption of rhein, berberine and baicalein can be employed to promote oral bioavailability of SHXXT.

Cancer prevention and therapy through the modulation of the tumor microenvironment

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

Upregulation of MAPK/Erk and PI3K/Akt pathways in ulcerative colitis-associated colon cancer

An extracellular signal like a cytokine or chemokine, secreted in the inflammatory microenvironment can activate the mitogen activated protein kinase (MAPK) pathway by binding to a cytokine receptor tyrosine kinase, which further activates tyrosine kinases such as Janus Kinase-3 (Jak-3). This signal is transferred from Jak-3 to the DNA in the nucleus of the cell by a chain of kinases, ultimately activating extracellular receptor kinase (Erk/MAPK). The latter phosphorylates c-myc, an oncogene, which alters the levels and activities of many transcription factors leading to cell survival, proliferation and invasion. The oncogenic PI3K pathway plays a similar role by activating c-myc, leading to cell survival and proliferation. The present study explores the role of ulcerative colitis in colon cancer by investigating the activities of tyrosine kinase activated MAPK pathway and various components of the PI3K pathway including PI3K, PTEN, PDK1, GSK3β, Akt, mTOR, Wnt and β-catenin. This was done by western blot and fluorescent immunohistochemical analysis of the above-mentioned proteins. Also, the morphological and histological investigation of the colonic samples from various animal groups revealed significant alterations as compared to the control in both inflammatory as well as carcinogenic conditions. These effects were reduced to a large extent by the co-administration of celecoxib, a second-generation non-steroidal anti-inflammatory drug (NSAID).

Berberine hydrochloride prevents postsurgery intestinal adhesion and inflammation in rats

Intestinal adhesion, characterized by connection of the loops of the intestine with other abdominal organs by fibrous tissue bands, remains an inevitable event of abdominal operations and can cause a number of complications. Berberine hydrochloride (berberine), a natural plant alkaloid derived from Chinese herbal medicine, is characterized by diverse pharmacological effects, such as anticancer and lower elevated blood glucose. This study is designed to investigate the effects of berberine on adhesion and inflammation after abdominal surgeries and the underlying molecular mechanisms. Adhesion severity grades and collagen deposition were assessed 14 days after surgery. We evaluated the levels of intercellular adhesion molecule-1 (ICAM-1) and inflammatory cytokines interleukin-1β (IL-1β), IL-6, transforming growth factor β (TGF-β), tumor necrosis factor-α (TNF-α), and examined transforming growth factor-activated kinase 1 (TAK1)/c-Jun N-terminal kinase (JNK) and TAK1/nuclear factor κB (NF-κB) signaling. The surgery group experienced the most severe adhesions, and berberine strikingly reduced the density and severity of adhesion. Results showed significant lower expression of IL-1β, IL-6, TGF-β, TNF-α, and ICAM-1, in berberine groups compared with the operation group. Activities of phosphorylated JNK and phosphorylated NF-κB were inhibited in the berberine groups compared with the surgery group. Our novel findings identified berberine hydrochloride as a promising strategy to prevent adhesion by downregulating ICAM-1 and reduce inflammation by inhibiting the TAK1/JNK and TAK1/NF-κB signaling after abdominal surgery, which brought out a good therapeutic approach for the development of clinical application for postoperative abdominal adhesion and inflammation.

Inhibition of Janus activated kinase-3 protects against myocardial ischemia and reperfusion injury in mice

Recent studies have documented that Janus-activated kinase (JAK)–signal transducer and activator of transcription (STAT) pathway can modulate the apoptotic program in a myocardial ischemia/reperfusion (I/R) model. To date, however, limited studies have examined the role of JAK3 on myocardial I/R injury. Here, we investigated the potential effects of pharmacological JAK3 inhibition with JANEX-1 in a myocardial I/R model. Mice were subjected to 45 min of ischemia followed by varying periods of reperfusion. JANEX-1 was injected 1 h before ischemia by intraperitoneal injection. Treatment with JANEX-1 significantly decreased plasma creatine kinase and lactate dehydrogenase activities, reduced infarct size, reversed I/R-induced functional deterioration of the myocardium and reduced myocardial apoptosis. Histological analysis revealed an increase in neutrophil and macrophage infiltration within the infarcted area, which was markedly reduced by JANEX-1 treatment. In parallel, in in vitro studies where neutrophils and macrophages were treated with JANEX-1 or isolated from JAK3 knockout mice, there was an impairment in the migration potential toward interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1), respectively. Of note, however, JANEX-1 did not affect the expression of IL-8 and MCP-1 in the myocardium. The pharmacological inhibition of JAK3 might represent an effective approach to reduce inflammation-mediated apoptotic damage initiated by myocardial I/R injury.

Stability-Indicating Validated HPLC Method for Analysis of Berberine Hydrochloride and Trimethoprim in Pharmaceutical Dosage Form

A stability-indicating HPLC method was developed and validated for the determination of berberine hydrochloride and trimethoprim in pharmaceutical dosage form in the presence of degradation products. The proposed RP-HPLC method utilizes an Agilent TC-C18, 4.6 mm × 250 mm, 5 μm, column using a mobile phase consisting of acetonitrile-50 mM potassium dihydrogen phosphate (30 : 70, v/v, pH adjusted to 3 with orthophosphoric acid) at a flow rate of 1.0 mL/min and UV detection at 271 nm. The linearity of berberine hydrochloride and trimethoprim was in the range of 2 to 60 μg/mL (r=0.9996) and 1 to 30 μg/mL (r=0.9995), respectively. Repeatability and intermediate precisions were also determined with percentage relative standard deviation (% RSD) less than 2.0%. The limits of detection were found to be 9.8 ng/mL for berberine hydrochloride and 2.5 ng/mL for trimethoprim. The mean recoveries for berberine hydrochloride and trimethoprim were 99.8 and 98.8%, respectively. The stability of the two drugs was determined under different conditions and the proposed method has shown effective separation for their degradation products. And the proposed assays method can thus be considered stability-indicating.

Specific Jak3 Downregulation in Lymphocytes Impairs γc Cytokine Signal Transduction and Alleviates Antigen-driven Inflammation In Vivo

Jak3, one of the four members comprising the Jak family of cytosolic tyrosine kinases, has emerged as a promising target for nontoxic immunotherapies. Although a number of Jak inhibitors has already demonstrated efficacy, they suffer from secondary effects apparently associated to their pan-Jak activity. However, whether selective Jak3 inhibition would afford therapeutic efficacy remains unclear. To address this question we have investigated the immunosuppressive potential of selective Jak3 intervention in lymphocytes using RNA interference (RNAi) technology in vitro and in vivo. Using synthetic small interference RNA (siRNA) sequences we achieved successful transfections into human and mouse primary T lymphocytes. We found that Jak3 knockdown was sufficient to impair not only interleukin-2 (IL-2) and T cell receptor (TCR)-mediated cell activation in vitro, but also antigen-triggereds welling, inflammatory cell infiltration, and proinflammatory cytokine raise in vivo. Furthermore, Jak1 (which mediates γc cytokine signaling in conjunction with Jak3) cosilencing did not provide higher potency to the aforementioned immunosuppressant effects. Our data provides direct evidences indicating that Jak3 protein plays an important role in γc cytokine and antigen-mediated T cell activation and modulates Th1-mediated inflammatory disorders, all in all highlighting its potential as a target in immunosuppressive therapies.