NKX6.3 protects against gastric mucosal atrophy by downregulatingβ-amyloid production

BACKGROUND Atrophic gastritis is characterized by loss of appropriate glands and reduction in gastric secretory function due to chronic inflammatory processes in gastric mucosa. Moreover, atrophic gastritis is considered as a precancerous condition of gastric cancer. However, little is known about the molecular mechanism underlying gastric mucosal atrophy and its contribution to gastric carcinogenesis.Thus, we hypothesized that transcription factor NKX6.3 might be involved in maintaining gastric epithelial homeostasis by regulating amyloid β(Aβ)production.AIM To determine whether NKX6.3 might protect against gastric mucosal atrophy by regulating Aβ production.METHODS We identified NKX6.3 depletion induced cell death by cell count and Western blot assay. Production and mechanism of Aβ oligomer were analyzed by enzymelinked immunosorbent assay, Western blot, immunoprecipitation, real-timequantitative polymerase chain reaction and immunofluorescence analysis. We further validated the correlation between expression of NKX6.3, Helicobacter pylori CagA, Aβ oligomer, apolipoprotein E(ApoE), and β-secretase 1(Bace1) in 55 gastric mucosae.RESULTS NKX6.3 depletion increased both adherent and floating cell populations in HFE-145 cells. Expression levels of cleaved caspase-3,-9, and poly ADP ribose polymerase were elevated in floating HFE-145^(shNKX6.3) cells. NKX6.3 depletion produced Aβ peptide oligomers, and increased expression of ApoE, amyloid precursor protein, Aβ, Bace1, low-density lipoprotein receptor, nicastrin, high mobility group box1, and receptor for advanced glycosylation end product proteins. In immunoprecipitation assay, γ-secretase complex was stably formed only in HFE-145^(shNKX6.3) cells. In gastric mucosae with atrophy, expression of Aβpeptide oligomer, ApoE, and Bace1 was detected and inversely correlated with NKX6.3 expression. Treatment with recombinant Aβ 1-42 produced Aβoligomeric forms and decreased cell viability in HFE-145^(shNKX6.3) cells. Additionally,NKX6.3 depletion increased expression of inflammatory cytokines and cyclooxygenase-2.CONCLUSION NKX6.3 inhibits gastric mucosal atrophy by regulating Aβ accumulation and inflammatory reaction in gastric epithelial cells.

NKX6.3对食管癌细胞增殖、凋亡及侵袭的影响及作用机制

目的探讨NKX6.3对食管癌细胞增殖、凋亡及侵袭的影响及可能的作用机制。方法人食管癌EC9706细胞分别转染NKX6.3(NKX6.3组)和空白质粒(miR-NC组),设空白对照组(Control组)。CCK-8法检测细胞增殖情况,流式细胞仪检测细胞内活性氧、线粒体膜电位及细胞凋亡情况,Transwell法检测细胞侵袭能力,Western blot检测增殖相关蛋白Ki67、侵袭相关蛋白(Vimentin、E-cadherin及N-cadherin),凋亡相关蛋白(Bcl-2、Bax及Caspase-3)的表达。结果 Control组、miR-NC组和NKX6.3组食管癌EC9706细胞中NKX6.3表达、细胞增殖能力、细胞内活性氧、线粒体膜电位、细胞凋亡及侵袭能力,以及Ki67、Vimentin、E-cadherin、N-cadherin、Bcl-2、Bax及Caspase-3蛋白表达差异均有统计学意义(P<0.01)。其中,NKX6.3组NKX6.3表达量、细胞内活性氧,细胞凋亡率,Vimentin、E-cadherin、Bax及Caspase-3蛋白表达水平较miR-NC组升高;而线粒体膜电位、细胞增殖率、细胞侵袭数目、N-cadherin及Bcl-2蛋白表达水平降低(P<0.01)。结论NKX6.3可抑制食管癌细胞增殖和侵袭,促进细胞凋亡,该作用可能通过调控食管癌细胞中的增殖凋亡相关蛋白表达及活性氧水平实现。

益胃消瘀颗粒对萎缩性胃炎大鼠胃黏膜肠化的影响

目的:探讨益胃消瘀颗粒治疗萎缩性胃炎胃黏膜肠化的治疗作用与机制。方法:8周龄雄性SD大鼠60只,按随机数字表法分为空白组、模型组、胃复春组、益胃消瘀颗粒高剂量组、益胃消瘀颗粒中剂量组、益胃消瘀颗粒低剂量组共6组,N-甲基-N’-硝基-N-亚硝基胍(MNNG)和法莫替丁联合造模。6个月及7个月后分次抽检3只,造模成功后开始进入实验给药阶段,给药3个月后观察大鼠胃黏膜组织学改变,RT-qPCR检测胃黏膜标本中尾型同源盒转录因子2(caudal-related homeobox transcription factor2,CDX2)、干细胞转录调控因子性别决定相关基因簇2(Sex de-termining region Y-box 2,SOX2)的表达,Western blot检测胃黏膜中NK6同源框蛋白3(NK6 Homeobox Protein 3,NKX6.3)、骨形成蛋白4(bone morphogenic protein 4,BMP4)的表达。结果:光镜下观察胃黏膜病理组织,模型组可见黏膜萎缩及肠化,益胃消瘀颗粒高、中剂量组及胃复春组萎缩及肠化均较模型组明显改善,低剂量组萎缩及肠化有所减轻;与空白组比较,模型组NKX6.3、Sox2表达明显下降,BMP4、CDx2表达明显升高;与模型组比较,益胃消瘀颗粒高、中剂量组和胃复春组NKX6.3表达明显上升,益胃消瘀颗粒高、中、低剂量组及胃复春组Sox2表达明显升高,BMP4、CDx2表达明显下降。结论:益胃消瘀颗粒能够改善萎缩性胃炎肠化大鼠胃黏膜组织病理形态,其机制可能与激活NKX6.3、下调Cdx2、上调Sox2和抑制BMP4表达有关。