ABSTRACT
OBJECTIVE Although it is generally believed that nicotine accounts for the beneficial effect of smoking on ulcerative colitis, the underlying mechanisms remain not well understood. Our previous finding that nicotine inhibits inflammatory responses through inducing miRNA-124 prompted us to ask whether the miRNA is involved in the protective action of nicotine on UC. METHODS MiR-124 expres-sion in colon tissues and cells was determined by q-PCR and in situ hybridization.The effect of miR-124 on protective role of nicotine in ulcerative colitis was evaluated in DSS-treated mice and IL-6-treated Caco-2 colon epithelial cells. Expression of p-STAT3/STAT3 was detected by immunohistochemistry and Western-blot analysis. RESULTS miR-124 expression is upregulated in colon tissues from UC patients and DSS-induced colitis mice. Nicotine treatment further elevated miR-124 level in lympho-cytes isolated from human ulcerative colonic mucosa and ulcerative colon tissues from DSS mice,both in infiltrated lymphocytes and epithelial cells. Administration of nicotine also reduced weight loss, improved DAI and decreased HE score in DSS-induced colitis mice.Moreover,knockdown of miR-124 in vivo significantly diminished the beneficial effect of nicotine on murine colitis, and in vitro on IL-6-treated Caco-2 colon epithelial cells.Further analysis indicated that nicotine inhibited STAT3 activation in vivo and in IL-6-treated Caco-2 colon epithelial cells and Jurkat human T lymphocytes,in which miR-124 knockdown led to increased activation of STAT3. Blocking STAT3 activity alone is beneficial for DSS colitis and also abolished nicotine′s protective effect in this model.CONCLUSION These data indicated that nicotine exerts its protective action in UC through inducing miR-124 and its effect on STAT3, and suggest that the miR-124/STAT3 system is a potential target for the therapeutic intervention of UC.
ABSTRACT
Aim To observe the effect of icariside Ⅱ(ICS Ⅱ)on cardiomyocyte apoptosis in spontaneously hypertensive rats (SHR)and to explore its possible mechanism. Methods Thirty male 13-week-old SHRs were randomly divided into model group,ICS Ⅱ low, medium,high and positive drug group (n = 6),ho-mologous male Wistar-Kyoto rats as control group (n =6). After a week of adaptive feeding,ICS Ⅱ low,me-dium and high dose groups were given ICS Ⅱ 4,8,16 mg · kg - 1 (ig,qd),and the positive drug group was given losartan 20 mg·kg - 1 . At the same time,the WKY and SHR group were given equal volume double distilled water. After 12 weeks of administration,the blood pressure was measured in rats. Then,the rats were sacrificed and the left ventricles were separated in order to calculate the left ventricular mass index. HE staining was used to observe the pathological changes of the left ventricle,and the apoptosis of the left ventricu-lar myocardium was detected by TUNEL staining. The expressions of Bcl-2 and Bax mRNA in left ventricle were detected by real time RT-PCR,and Bcl-2,Bax and cleaved-caspase-3 protein expressions were detec-ted by Western blot. Results Compared with WKY group,the blood pressure and left ventricular mass in-dex increased in SHR group (P < 0. 05),and the my-ocardial cell arrangement was disordered and the cell hypertrophy and apoptosis were obvious,accompanied by rupture of filament ;the level of Bax mRNA was up-regulated (P < 0. 05),and Bcl-2 mRNA was down-regulated (P < 0. 05 );the expressions of Bax and cleaved-caspase-3 protein were up-regulated (P <0. 05),and the level of Bcl-2 protein was down-regu-lated (P < 0. 05 ),and the ratio of Bax / Bcl-2 in-creased (P < 0. 05). Compared with SHR group,the blood pressure and left ventricular mass index de-creased in ICS Ⅱ middle,high group and the positive drug group (P < 0. 05);moreover,the arrangement of myocardial cells became more orderly,the cell hyper-trophy and the apoptosis of myocardial cells were im-proved;the level of Bax mRNA was down-regulated and Bcl-2 mRNA was up-regulated (P < 0. 05);the expression of Bax and cleaved-caspase3 protein were down-regulated and the level of Bcl-2 protein was up-regulated (P < 0. 05 );the ratio of Bax / Bcl-2 de-creased (P < 0. 05). Conclusions ICS Ⅱ can im-prove the left ventricular cardiomyocytes apoptosis in SHR,and its mechanism is related to the decrease of blood pressure and the inhibition of mitochondrial ap-optosis pathway.
ABSTRACT
Colorectal cancer (CRC) as a common malignancy in the digestive tract, its incidence and mortality increase significantly in China. Cancer stem cells (CSCs) are defined as a small fraction of tumor initiating cells that are endowed with both self-renewal and tumor growth potential. They may be responsible for tumor progression, metastasis, relapse and drug-resistance. Therefore, the isolation and characterization of tumorigenic CSCs in CRC may help to devise novel diagnostic and therapeutic procedures. This review briefly discusses the most recent advances in research on colorectal cancer stem cells including definition of the cancer stem cells, origin and specific markers of the colorectal CSCs. Transduction signal pathway involved in CSCs, potential therapeutic strategies targeting CSCs, and current issues in CSCs related research are also discussed.