Objective: This study aims to investigate the associations between genetic variations of pyroptosis pathway related key genes and adverse events (AEs) of postoperative chemoradiotherapy (CRT) in patients with rectal cancer. Methods: DNA was extracted from the peripheral blood which was collected from 347 patients before CRT. Sequenom MassARRAY was used to detect the genotypes of 43 haplotype-tagging single nucleotide polymorphisms (htSNPs) in eight pyroptosis genes, including absent in melanoma 2 (AIM2), caspase-1 (CASP1), caspase-4(CASP4), caspase-5 (CASP5), caspase-11 (CASP11), gasdermin D (GSDMD), gasdermin E (GSDME) and NLR family pyrin domain containing 3 (NLRP3). The associations between 43 htSNPs and AEs were evaluated by the odd ratios (ORs) and 95% confidence intervals (CIs) by unconditional logistic regression models, adjusted for sex, age, clinical stage, tumor grade, Karnofsky performance status (KPS), surgical procedure, and tumor location. Results: Among the 347 patients with rectal cancer underwent concurrent CRT with capecitabine after surgery, a total of 101(29.1%) occurred grade ≥ 2 leukopenia. rs11226565 (OR=0.41, 95% CI: 0.21-0.79, P=0.008), rs579408(OR=1.54, 95% CI: 1.03-2.29, P=0.034) and rs543923 (OR=0.63, 95% CI: 0.41-0.98, P=0.040) were significantly associated with the occurrence of grade ≥ 2 leukopenia. One hundred and fifty-six (45.0%) had grade ≥ 2 diarrhea, two SNPs were significantly associated with the occurrence of grade ≥ diarrhea, including CASP11 rs10880868 (OR=0.55, 95% CI: 0.33-0.91, P=0.020) and GSDME rs2954558 (OR=1.52, 95% CI: 1.01-2.31, P=0.050). In addition, sixty-six cases (19.0%) developed grade ≥2 dermatitis, three SNPs that significantly associated with the risk of grade ≥2 dermatitis included GSDME rs2237314 (OR=0.36, 95% CI: 0.16-0.83, P=0.017), GSDME rs12540919 (OR=0.52, 95% CI: 0.27-0.99, P=0.045) and NLRP3 rs3806268 (OR=1.51, 95% CI: 1.03-2.22, P=0.037). There was no significant difference in the association between other genetic variations and AEs of rectal cancer patients (all P>0.05). Surgical procedure and tumor location had great impacts on the occurrence of grade ≥2 diarrhea and dermatitis (all P<0.01). Conclusion: The genetic variants of CASP4, CASP11, GSDME and NLRP3 are associated with the occurrence of AEs in patients with rectal cancer who received postoperative CRT, suggesting they may be potential genetic markers in predicting the grade of AEs to achieve individualized treatment of rectal cancer.
Humans ; Pyroptosis ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Gasdermins ; Chemoradiotherapy/adverse effects* ; Rectal Neoplasms/surgery* ; Caspases/metabolism* ; Diarrhea/chemically induced* ; Leukopenia/genetics* ; Genetic Variation ; Dermatitis

This study aims to investigate the effect and mechanism of saikosaponin D on the proliferation, apoptosis, and autophagy of pancreatic cancer Panc-1 cells. The cell counting kit(CCK-8) was used to examine the effects of 7, 10, 13, 16, 19, 22, 25, and 28 μmol·L~(-1) saikosaponin D on the proliferation of Panc-1 cells. Three groups including the control(0 μmol·L~(-1)), low-concentration(10 μmol·L~(-1)) saikosaponin D, and high-concentration(16 μmol·L~(-1)) saikosaponin D groups were designed. The colony formation assay was employed to measure the effect of saikosaponin D on the colony formation rate of Panc-1 cells. The cells treated with saikosaponin D were stained with hematoxylin-eosin(HE), and the changes of cell morphology were observed. Hoechst 33258 fluorescent staining was used to detect the effect of saikosaponin D on the cell apoptosis. The autophagy staining assay kit with MDC was used to examine the effect of saikosaponin D on the autophagy of Panc-1 cells. Western blot and immunocytochemistry(ICC) were employed to examine the effect of saikosaponin D on the expression levels and distribution of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), cysteine-aspartic acid protease-3(caspase-3), cleaved caspase-3, autophagy-associated protein Beclin1, microtubule-associated protein light chain 3(LC3), protein kinase B(Akt), phosphorylated protein kinase B(p-Akt), mammalian target of rapamycin(mTOR), and phosphorylated mammalian target of rapamycin(p-mTOR). The results showed that compared with the control group, saikosaponin D decreased the proliferation rate of Panc-1 cells in a dose-dependent and time-dependent manner. The colony formation rate of the cells significantly decreased after saikosaponin D treatment. Compared with the control group, the cells treated with saikosaponin D became small, accompanied by the formation of apoptotic bodies. The saikosaponin D groups showed increased apoptosis rate and autophagic vesicle accumulation. Compared with the control group, saikosaponin D up-regulated the expression of Bax, cleaved caspase3, Beclin1, LC3Ⅱ/LC3Ⅰ and down-regulated the expression of Bcl-2, caspase-3, p-Akt/Akt, and p-mTOR/mTOR. In addition, these proteins mainly existed in the cytoplasm. In conclusion, saikosaponin D can inhibit the proliferation and induce the apoptosis and autophagy of Panc-1 cells via inhibiting the Akt/mTOR pathway.
Humans ; Proto-Oncogene Proteins c-akt/genetics* ; Caspase 3 ; bcl-2-Associated X Protein ; Beclin-1/pharmacology* ; Cell Line, Tumor ; TOR Serine-Threonine Kinases/genetics* ; Apoptosis ; Pancreatic Neoplasms/drug therapy* ; Caspases ; Autophagy

OBJECTIVE: To observe the effect of Tongdu Tiaoshen (promoting the circulation of the governor vessel and regulating the spirit) electroacupuncture (EA) pretreatment on pyroptosis mediated by peroxisome proliferators-activated receptor γ (PPARγ) of the cerebral cortex in rats with cerebral ischemia reperfusion injury (CIRI) and explore the potential mechanism of EA for the prevention and treatment of CIRI. METHODS: A total of 110 clean-grade male SD rats were randomly divided into a sham-operation group, a model group, an EA group, an EA + inhibitor group and an agonist group, 22 rats in each group. In the EA group, before modeling, EA was applied to "Baihui" (GV 20), "Fengfu" (GV 16) and "Dazhui" (GV 14), with disperse-dense wave, 2 Hz/5 Hz in frequency, 1 to 2 mA in intensity, lasting 20 min; once a day, consecutively for 7 days. On the base of the intervention as the EA group, on the day 7, the intraperitoneal injection with the PPARγ inhibitor, GW9662 (10 mg/kg) was delivered in the EA + inhibitor group. In the agonist group, on the day 7, the PPARγ agonist, pioglitazone hydrochloride (10 mg/kg) was injected intraperitoneally. At the end of intervention, except the sham-operation group, the modified thread embolization method was adopted to establish the right CIRI model in the rats of the other groups. Using the score of the modified neurological severity score (mNSS), the neurological defect condition of rats was evaluated. TTC staining was adopted to detect the relative cerebral infarction volume of rat, TUNEL staining was used to detect apoptosis of cerebral cortical nerve cells and the transmission electron microscope was used to observe pyroptosis of cerebral cortical neural cells. The positive expression of PPARγ and nucleotide-binding to oligomerization domain-like receptor protein 3 (NLRP3) in the cerebral cortex was detected with the immunofluorescence staining. The protein expression of PPARγ, NLRP3, cysteinyl aspartate specific protease-1 (caspase-1), gasdermin D (GSDMD) and GSDMD-N terminal (GSDMD-N) in the cerebral cortex was detected with Western blot. Using the quantitative real-time fluorescence-PCR, the mRNA expression of PPARγ, NLRP3, caspase-1 and GSDMD of the cerebral cortex was detected. The contents of interleukin (IL)-1β and IL-18 in the cerebral cortex of rats were determined by ELISA. RESULTS: Compared with the sham-operation group, the mNSS, the relative cerebral infarction volume and the TUNEL positive cells rate were increased (P<0.01), pyroptosis was severe, the protein and mRNA expression levels of PPARγ, NLRP3, caspase-1 and GSDMD were elevated (P<0.01); and the protein expression of GSDMD-N and contents of IL-1β and IL-18 were increased (P<0.01) in the model group. When compared with the model group, the mNSS, the relative cerebral infarction volume and the TUNEL positive cells rate were decreased (P<0.01), pyroptosis was alleviated, the protein and mRNA expression levels of PPARγ were increased (P<0.01), the protein and mRNA expression levels of NLRP3, caspase-1 and GSDMD were decreased (P<0.01), the protein expression of GSDMD-N was reduced (P<0.01); and the contents of IL-1β and IL-18 were lower (P<0.01) in the EA group and the agonist group; while, in the EA + inhibitor group, the protein expression of PPARγ was increased (P<0.01), the protein and mRNA expression levels of NLRP3 and GSDMD were decreased (P<0.01, P<0.05), the mRNA expression of caspase-1 was reduced (P<0.01); and the contents of IL-1β and IL-18 were lower (P<0.01). When compared with the EA + inhibitor group, the mNSS, the relative cerebral infarction volume and the TUNEL positive cells rate were decreased (P<0.05, P<0.01), pyroptosis was alleviated, the protein and mRNA expression levels of PPARγ were increased (P<0.01), the protein and mRNA expression levels of NLRP3, caspase-1 and GSDMD were decreased (P<0.01), the protein expression of GSDMD-N was reduced (P<0.01); and the contents of IL-1β and IL-18 were declined (P<0.01) in the EA group. Compared with the agonist group, in the EA group, the relative cerebral infarction volume and the TUNEL positive cells rate were increased (P<0.05, P<0.01), the mRNA expression of PPARγ was decreased (P<0.01) and the protein expression of GSDMD-N was elevated (P<0.05); and the contents of IL-1β and IL-18 were higher (P<0.01). CONCLUSION Tongdu Tiaoshen EA pretreatment can attenuate the neurological impairment in the rats with CIRI, and the underlying mechanism is related to the up-regulation of PPARγ inducing the inhibition of NLRP3 in the cerebral cortex of rats so that pyroptosis is affected.
Male ; Animals ; Rats ; Rats, Sprague-Dawley ; PPAR gamma/genetics* ; Pyroptosis ; Interleukin-18 ; Electroacupuncture ; NLR Family, Pyrin Domain-Containing 3 Protein ; Cerebral Cortex ; Cerebral Infarction/therapy* ; Caspases ; RNA, Messenger

This study aims to explore the effect of Sini Decoction on Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB) signaling pathway in the mice with allergic asthma(AA). Forty-eight SPF-grade BALB/c mice were randomly assigned into a blank control group, a model group, a dexamethasone group, and high-, medium-, and low-dose Sini Decoction groups, with 8 mice in each group. The sensitization solution made of ovalbumin and aluminum hydroxide powder was injected intraperitoneally in other groups except the blank control group which was injected with an equal volume of normal saline. The solution(or normal saline) was injected three times in total with an interval of 7 days. At the same time of sensitization, external cold stimulation and ice water were administered in a 4 ℃ climate box for 20 min every day. After modeling, the mice in each group were administrated with corresponding drugs by gavage for 3 weeks. At the end of administration, pentobarbital sodium(30 mg·kg~(-1)) was used for anesthesia, and then the samples were collected for the determination of various indexes. The phenol red test was conducted to evaluate tracheal excretion function. The histopathological changes of lung tissue were observed via hematoxylin-eosin(HE) staining. Masson staining was employed to reveal the deposition of blue collagen fibers around bronchi in lung tissue and the area occupied by blue collagen fibers was calculated. Immunofluorescence method was used to measure the expression of bronchial type Ⅰ collagen(Col-Ⅰ) and α-smooth muscle actin(α-SMA). The protein and mRNA levels of TLR4, NF-κB, cysteinyl aspartate specific proteinase-1(caspase-1), and interleukin-13(IL-13) were determined by Western blot and real-time fluorescence quantitative polymerase chain reaction(real-time PCR), respectively. Compared with the model group, Sini Decoction significantly increased the phenol red excretion from trachea, lowered the lung inflammation score, reduced subepithelial collagen deposition, and decreased Col-Ⅰ and α-SMA levels. Furthermore, the decoction down-regulated the protein and mRNA levels of TLR4, NF-κB, caspase-1, and IL-13 in mouse lung tissue. In conclusion, Sini Decoction can improve air remodeling by inhibiting the TLR4/NF-κB signaling pathway.
Mice ; Animals ; NF-kappa B/metabolism* ; Airway Remodeling ; Interleukin-13/pharmacology* ; Toll-Like Receptor 4/genetics* ; Saline Solution/pharmacology* ; Phenolsulfonphthalein/pharmacology* ; Asthma/genetics* ; Signal Transduction ; Mice, Inbred BALB C ; RNA, Messenger ; Caspases

Curcumae Rhizoma is a Chinese medicinal herb that is contraindicated during pregnancy. Cold-congelation and blood-stasis are corresponding syndromes to Curcumae Rhizoma. Whether syndrome-based treatment is associated with developmental neurotoxicity of Curcumae Rhizoma remains to be unclear. To verify the theory of traditional Chinese medicine of "syndrome-based treatment during pregnancy", the present study induced the mice blood stasis model by immersing mice in ice water. Pregnant C57 BL/6 wild type(WT) mice and pregnant Nrf2 knock out(KO) mice were randomly divided into control groups and Rhizoma Curcumae exposure groups. The mice were exposed to Rhizoma Curcumae during day 5 to day 18 after pregnancy. The neurodevelopment was examined to evaluate the differences of developmental neurotoxicity between normal and blood-stasis pregnant mice exposed to Rhizoma Curcumae. caspase-3 and caspase-9 activity in brain of the offspring were measured by colorimetric assays. Bcl-2 mRNA and protein expression in brain of the offspring were examined by Real-time RT-PCR and Western blot, respectively. According to the findings, C57 BL/6 mice exposed to Rhizoma Curcumae(10.0 g·kg~(-1)) had a longer positive occurring time of the surface righting reflex test of offspring and higher caspase-3 and caspase-9 activities in brain of offspring, compared with the normal control group, but with no significant change in those of blood-stasis pregnant mice offspring. However, mice exposed to Rhizoma Curcumae(10.0 g·kg~(-1)) showed no change in Bcl-2 gene expression and p38 MAPK phosphorylation in brain of the offspring. Nrf2 gene knockout using CRISPR/Cas9 resulted in a longer positive occurring time of the surface righting reflex test of offspring and higher caspase-3 and caspase-9 activities in brain of offspring. In conclusion, developmental neurotoxicity of the blood-stasis pregnant mice exposed to Rhizoma Curcumae was weaker than that of the normal pregnant mice. Nrf2 activation involved in the phenomenon of Rhizoma Curcumae of "syndrome-based treatment during pregnancy", but the upstream signal pathway mechanism value shall be further investigated.
Animals ; Apoptosis ; Brain ; drug effects ; Caspases ; genetics ; Curcuma ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Female ; Maternal Exposure ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; NF-E2-Related Factor 2 ; genetics ; Pregnancy ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; Random Allocation ; Rhizome ; chemistry ; Signal Transduction

The underground cane of Schizocapsa plantaginea (Hance) has long been used by Chinese ethnic minority as a constituent of anti-cancer formulae. Saponins are abundant secondary metabolic products located in the underground cane of this plant. The potential therapeutic effects of total saponins isolated from Schizocapsa plantaginea (Hance) (SSPH) on human hepatocellular carcinoma (HCC) were tested in vitro in human liver cancer cell lines, SMMC-7721 and Bel-7404. Apoptosis and cell cycle arrest were determined using flow cytometry, caspase activation was determined by ELISA, and PARP, cleaved PARP, mitogen-activated protein kinase (MAPK) expression and phosphorylation were measured using Western blotting analysis. In vivo anti-HCC effects of SSPH were verified in nude mouse xenograft model. SSPH exerted markedly inhibitory effect on HCC cell proliferation in time- and concentration-dependent manner. Moreover, SSPH significantly induced apoptosis through caspase-dependent signaling and arrested cell cycle at G/M phase. These anti-proliferation effects of SSPH were associated with up-regulated phosphorylation of extracellular signal-regulated kinase-1/2 (Erk1/2) and c-jun-NH2-kinase-1/2 (JNK1/2) and reduced phosphorylation of p38MAPK. Furthermore, inhibitors of ERK, UO126, and JNK, SP600125 inhibited the anti-proliferation effects by SSPH, suggesting that Erk and JNK were the effector molecules in SSPH induced anti-proliferative action. During in vivo experiments, SSPH was found to inhibit xenograft tumor growth in nude mice, with a similar mechanism in vitro. Our study confirmed that SSPH exerted antagonistic effects on human liver cancer cells both in vitro and in vivo. Molecular mechanisms underlying SSPH action might be closely associated with MAPK signaling pathways. These results indicated that SSPH has potential therapeutic effects on HCC.
Animals ; Antineoplastic Agents ; isolation & purification ; pharmacology ; toxicity ; Apoptosis ; drug effects ; Caspases ; genetics ; metabolism ; Cell Cycle Checkpoints ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Dioscoreaceae ; chemistry ; Heterografts ; drug effects ; growth & development ; Humans ; Inhibitory Concentration 50 ; Liver Neoplasms ; drug therapy ; metabolism ; pathology ; MAP Kinase Signaling System ; drug effects ; Mice ; Mice, Nude ; Phosphorylation ; drug effects ; Plant Tubers ; chemistry ; Poly (ADP-Ribose) Polymerase-1 ; metabolism ; Saponins ; isolation & purification ; pharmacology ; toxicity

Entamoeba histolytica is a tissue-invasive protozoan parasite causing dysentery in humans. During infection of colonic tissues, amoebic trophozoites are able to kill host cells via apoptosis or necrosis, both of which trigger IL-8-mediated acute inflammatory responses. However, the signaling pathways involved in host cell death induced by E. histolytica have not yet been fully defined. In this study, we examined whether calpain plays a role in the cleavage of pro-survival transcription factors during cell death of colonic epithelial cells, induced by live E. histolytica trophozoites. Incubation with amoebic trophozoites induced activation of m-calpain in a time- and dose-dependent manner. Moreover, incubation with amoebae resulted in marked degradation of STAT proteins (STAT3 and STAT5) and NF-kappaB (p65) in Caco-2 cells. However, IkappaB, an inhibitor of NF-kappaB, was not cleaved in Caco-2 cells following adherence of E. histolytica. Entamoeba-induced cleavage of STAT proteins and NF-kappaB was partially inhibited by pretreatment of cells with a cell-permeable calpain inhibitor, calpeptin. In contrast, E. histolytica did not induce cleavage of caspase-3 in Caco-2 cells. Furthermore, pretreatment of Caco-2 cells with a calpain inhibitor, calpeptin (but not the pan-caspase inhibitor, z-VAD-fmk) or m-calpain siRNA partially reduced Entamoeba-induced DNA fragmentation in Caco-2 cells. These results suggest that calpain plays an important role in E. histolytica-induced degradation of NF-kappaB and STATs in colonic epithelial cells, which ultimately accelerates cell death.
Caco-2 Cells ; Calcium-Binding Proteins ; Calpain/genetics/metabolism ; Caspase 3/genetics/metabolism ; Caspases ; *Cell Death ; Colon/cytology ; Entamoeba histolytica/*physiology ; Epithelial Cells/cytology/parasitology ; Humans ; I-kappa B Proteins/metabolism ; Intestinal Mucosa/cytology ; NF-kappa B/genetics/*metabolism ; RNA Interference ; RNA, Small Interfering ; STAT3 Transcription Factor/genetics/*metabolism ; STAT5 Transcription Factor/genetics/*metabolism ; Signal Transduction

OBJECTIVETo evaluate whether Shenfu injection (SFI) protects against cardiac myocyte injury induced by Fupian injection (FPI) in vitro.

METHODSH9c2 cells were separately treated with FPI, Renshen injection (RSI) and SFI. Cell viability, lactate dehydrogenase (LDH) release, spontaneous beating rate of primative cardical cells, caspase-3/7 activity, cell apoptosis, and cytochrome P450 2J3 (CYP2J3) mRNA expression were analyzed.

RESULTSThe viability of H9c2 cells treated with SFI (37 and 75 mg/mL) was significantly higher than that of H9c2 cells treated with FPI (25 and 50 mg/mL) (P<0.05, P<0.01, respectively). LDH activity of H9c2 cells treated with SFI (75 mg/mL) was significantly decreased (P<0.01) compared with that of H9c2 cells treated with FPI (50 mg/mL). SFI (150 mg/mL) significantly attenuated FPI (100 mg/mL)-induced spontaneous beating rate decrease in primary myocardial cells after 4-hour treatment. Compared with FPI (12 and 25 mg/mL), SFI (18 and 37 mg/mL) treatment could effectively reverse the change of caspase-3/7 activity (P<0.01 and P<0.01, respectively). Compared with FPI (6 and 25 mg/mL), apoptotic cells decreased significantly (P<0.05, P<0.01, respectively) when H9c2 cells were incubated with SFI (9 and 37 mg/mL). The expression of CYP2J3 mRNA was down-regulated by FPI, while RSI and SFI could up-regulate the expression of CYP2J3 (P<0.01), which suggested the potential mechanism of protection of RSI against cardiac myocyte damage induced by FPI treatment.

CONCLUSIONThese observations indicate that SFI has the potential to exert cardioprotective effects against FPI toxicity. The effect was possibly correlated with the activation of CYP2J3.

Animals ; Apoptosis ; drug effects ; Caspases ; metabolism ; Cell Survival ; drug effects ; Cells, Cultured ; Cytochrome P-450 Enzyme System ; genetics ; physiology ; Drugs, Chinese Herbal ; pharmacology ; L-Lactate Dehydrogenase ; secretion ; Myocytes, Cardiac ; drug effects ; enzymology ; Rats

Fucoidan is an active component of seaweed, which inhibits proliferation and induces apoptosis of several tumor cells while the detailed mechanisms underlying this process are still not clear. In this study, the effect of Fucoidan on the proliferation and apoptosis of human breast cancer MCF-7 cells and the molecular mechanism of Fucoidan action were investigated. Viable cell number of MCF-7 cells was decreased by Fucoidan treatment in a dose-dependent manner as measured by MTT assay. Fucoidan treatment resulted in G1 phase arrest of MCF-7 cells as revealed by flow cytometry, which was associated with the decrease in the gene expression of cyclin D1 and CDK-4. Annexin V/PI staining results showed that the number of apoptotic cells was associated with regulation of cytochrome C, caspase-8, Bax and Bcl-2 at transcriptional and translational levels. Both morphologic observation and Hoechst 33258 assay results confirmed the pro-apoptotic effect of Fucoidan. Meanwhile, the ROS production was also increased by Fucoidan treatment, which suggested that Fucoidan induced oxidative damage in MCF-7 cells. The results of present study demonstrated that Fucoidan could induce G1 phase arrest and apoptosis in MCF-7 cells through regulating the cell cycle and apoptosis-related genes or proteins expression, and ROS generation is also involved in these processes.
Antineoplastic Agents ; chemistry ; pharmacology ; Apoptosis ; drug effects ; genetics ; Blotting, Western ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Caspase 8 ; genetics ; metabolism ; Caspases ; genetics ; metabolism ; Cell Proliferation ; drug effects ; Cell Size ; drug effects ; Cyclin D1 ; genetics ; metabolism ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; Cytochromes c ; genetics ; metabolism ; Dose-Response Relationship, Drug ; Fucus ; chemistry ; G1 Phase Cell Cycle Checkpoints ; drug effects ; genetics ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; MCF-7 Cells ; Microscopy, Fluorescence ; Molecular Structure ; Polysaccharides ; chemistry ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Reactive Oxygen Species ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; bcl-2-Associated X Protein ; genetics ; metabolism

The paracaspase MALT1 is essential for the activation of NF-κB in response to T cell receptor (TCR) stimulation. It recruits downstream TRAF6 and activates the E3 ligase activity of TRAF6 to polyubiquitinate several targets, which ultimately leads to NF-κB activation. Here we identified ubiquitin-specific protease 2a (USP2a) as a MALT1-associated protein by biochemical affinity purification. Endogenous USP2a constitutively interacted with TRAF6, but dynamically interacted with MALT1 and CARMA1 in a stimulation-dependent manner. RNA interference (RNAi)-mediated silencing of USP2a attenuated TCR-induced NF-κB activation and production of interleukin-2 (IL-2). In addition, the ubiquitination of MALT1 and TRAF6 were both suppressed by USP2a knockdown. By knockdown and reconstitution assays, we found that USP2a mediated the interaction between MALT1 and TRAF6 in a catalytic activity-dependent manner. Furthermore, USP2a deSUMOylated TRAF6. Our findings implicate that USP2a plays an important role in TCR signaling by deSUMOylating TRAF6 and mediating TRAF6-MALT1 interaction.
Caspases ; metabolism ; Endopeptidases ; deficiency ; genetics ; metabolism ; Gene Knockdown Techniques ; HEK293 Cells ; Humans ; Interleukin-2 ; biosynthesis ; Jurkat Cells ; Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein ; NF-kappa B ; metabolism ; Neoplasm Proteins ; metabolism ; Receptors, Antigen, T-Cell ; metabolism ; Signal Transduction ; Sumoylation ; TNF Receptor-Associated Factor 6 ; metabolism