我国弓形虫Chinese 1优势基因型感染对小鼠脑组织铁代谢影响

目的　探讨我国弓形虫Chinese 1优势基因型感染对宿主脑组织铁代谢及脑损伤的影响。方法　将20只C57BL/6（体质量15～17 g）小鼠随机分为对照组和感染组，每组10只。感染组每只小鼠腹腔注射4 000个弓形虫Chinese 1优势基因型TgCtwh3虫株速殖子，对照组小鼠注射等量无菌PBS，饲养6 d后处死小鼠并取其脑组织。采用电感耦合等离子体质谱法（inductively coupled plasma mass spectrometry, ICP⁃MS）检测小鼠脑组织铁元素水平；采用RNA芯片检测两组小鼠脑组织差异基因数目并对功能基因表达情况进行基因本体论（Gene Ontology, GO）功能富集；采用实时荧光定量PCR（fluorescent quantitative real⁃time PCR, qPCR）技术检测小鼠脑组织中弓形虫表面抗原1（Toxoplasma gondii surface antigen 1，TgSAG1）基因及部分锌铁调控蛋白（Zrt⁃ and Irt⁃like protein, ZIP）家族mRNA表达水平；采用光镜和电镜观察小鼠脑组织海马齿轮回（dentate gyrus, DG）超微结构；采用Western blotting检测谷胱甘肽过氧化物酶4（glutathione peroxidase 4, GPx4）蛋白表达水平；采用硫代巴比妥酸（TBA）法检测丙二醛（malondialdehyde, MDA）水平；采用免疫组化检测血管内皮生长因子（vascular endothelial growth factor, VEGF）蛋白表达光密度（optical density, OD）值。结果　光镜下可见感染组小鼠脑组织海马DG区细胞坏死，电镜下见感染组小鼠脑组织海马区出现胞质空泡化、核皱缩坏死、线粒体嵴断裂消融、自噬小体增加等超微结构变化。与对照组相比，感染组小鼠脑组织中铁元素水平上调[（32.92 ± 0.90） µg/g vs.（37.72 ± 1.10） µg/g；t = 3.397, P < 0.01]；RNA芯片检测感染组小鼠脑组织发现721个基因上调、276个基因下调，差异表达基因在金属离子结合能力上有明显富集。与对照组相比，感染组小鼠脑组织金属元素转运体ZIP2 mRNA表达水平上调（t = 8.659，P < 0.05）、GPx4表达下降[（1.046 ± 0.025） vs. （0.720 ± 0.101）；t = 3.129，P < 0.01]）、MDA水平升高[（4.37 ± 0.33） nmol/mgprot vs.（5.93 ± 0.54） nmol/mgprot；t = 2.451，P < 0.05）]、VEGF蛋白平均OD值上调[（0.348 3 ± 0.017 8） vs. （0.490 6 ± 0.010 5）；t = 6.641，P < 0.01]。结论　Chinese 1优势基因型弓形虫感染后，小鼠脑组织中铁元素蓄积、抗氧化能力下调、氧化应激水平升高，提示弓形虫感染可影响宿主脑组织铁代谢而导致脑损伤。     

Metabolism of non-steroidal anti-inflammatory drugs (NSAIDs) by Streptomyces griseolus CYP105A1 and its variants

In the field of drug development, technology for producing human metabolites at a low cost is required. In this study, we explored the possibility of using prokaryotic water-soluble cytochrome P450 (CYP) to produce human metabolites. Streptomyces griseolus CYP105A1 metabolizes various non-steroidal anti-inflammatory drugs (NSAIDs), including diclofenac, mefenamic acid, flufenamic acid, tolfenamic acid, meclofenamic acid, and ibuprofen. CYP105A1 showed 4′-hydroxylation activity towards diclofenac, mefenamic acid, flufenamic acid, tolfenamic acid, and meclofenamic acid. It should be noted that this reaction specificity was similar to that of human CYP2C9. In the case of mefenamic acid, another metabolite, 3′-hydroxymethyl mefenamic acid, was detected as a major metabolite. Substitution of Arg at position 73 with Ala in CYP105A1 dramatically reduced the hydroxylation activity toward diclofenac, flufenamic acid, and ibuprofen, indicating that Arg73 is essential for the hydroxylation of these substrates. In contrast, substitution of Arg84 with Ala remarkably increased the hydroxylation activity towards diclofenac, mefenamic acid, and flufenamic acid. Recombinant Rhodococcus erythrocyte cells expressing the CYP105A1 variant R84A/M239A showed complete conversion of diclofenac into 4′-hydroxydiclofenac. These results suggest the usefulness of recombinant R. erythropolis cells expressing actinomycete CYP, such as CYP105A1, for the production of human drug metabolites.     

ArgD of Mycobacterium tuberculosis is a functional N-acetylornithine aminotransferase with moonlighting function as an effective immune modulator

Mycobacterium tuberculosis (M. tuberculosis) encodes an essential enzyme acetyl ornithine aminotransferase ArgD (Rv1655) of arginine biosynthetic pathway which plays crucial role in M. tuberculosis growth and survival. ArgD catalyzes the reversible conversion of N-acetylornithine and 2 oxoglutarate into glutamate-5-semialdehyde and L-glutamate. It also possesses succinyl diaminopimelate aminotransferase activity and can thus carry out the corresponding step in lysine biosynthesis. These essential roles played by ArgD in amino acid biosynthetic pathways highlight it as an important metabolic chokepoint thus an important drug target. We showed that M. tuberculosis ArgD rescues the growth of ΔargD E. coli grown in minimal media validating its functional importance. Phylogenetic analysis of M. tuberculosis ArgD showed homology with proteins in gram positive bacteria, pathogenic and non-pathogenic mycobacteria suggesting the essentiality of this protein. ArgD is a secretory protein that could be utilized by M. tuberculosis to modulate host innate immunity as its moonlighting function. In-silico analysis predicted it to be a highly antigenic protein. The recombinant ArgD protein when exposed to macrophage cells induced enhanced production of pro-inflammatory cytokines TNF, IL6 and IL12 in a dose dependent manner. ArgD also induced the increased production of innate immune effector molecule NOS2 and NO in macrophages. We also demonstrated ArgD mediated activation of the canonical NFkB pathway. Notably, we also show that ArgD is a specific TLR4 agonist involved in the activation of pro-inflammatory signaling for sustained production of effector cytokines. Intriguingly, ArgD protein treatment activated macrophages to acquire the M1 phenotype through the increased surface expression of MHCII and costimulatory molecules CD80 and CD86. ArgD induced robust B-cell response in immunized mice, validating its antigenicity potential as predicted by the in-silico analysis. These properties of M. tuberculosis ArgD signify its functional plasticity that could be exploited as a possible drug target to combat tuberculosis.     

Chronic acidosis rewires cancer cell metabolism through PPARα signaling

The mechanisms linking tumor microenvironment acidosis to disease progression are not understood. Here, we used mammary, pancreatic, and colon cancer cells to show that adaptation to growth at an extracellular pH (pH_e) mimicking acidic tumor niches is associated with upregulated net acid extrusion capacity and elevated intracellular pH at physiological pH_e, but not at acidic pH_e. Using metabolic profiling, shotgun lipidomics, imaging and biochemical analyses, we show that the acid adaptation-induced phenotype is characterized by a shift toward oxidative metabolism, increased lipid droplet-, triacylglycerol-, peroxisome content and mitochondrial hyperfusion. Peroxisome proliferator-activated receptor-α (PPARA, PPARα) expression and activity are upregulated, at least in part by increased fatty acid uptake. PPARα upregulates genes driving increased mitochondrial and peroxisomal mass and β-oxidation capacity, including mitochondrial lipid import proteins CPT1A, CPT2 and SLC25A20, electron transport chain components, peroxisomal proteins PEX11A and ACOX1, and thioredoxin-interacting protein (TXNIP), a negative regulator of glycolysis. This endows acid-adapted cancer cells with increased capacity for utilizing fatty acids for metabolic needs, while limiting glycolysis. As a consequence, the acid-adapted cells exhibit increased sensitivity to PPARα inhibition. We conclude that PPARα is a key upstream regulator of metabolic changes favoring cancer cell survival in acidic tumor niches.     

补中益气汤对于肝再生线粒体能量代谢的研究概况＊

肝再生的机制非常复杂，线粒体功能障碍所引起的能量供给不足是影响因素之一，但其机理亟待研究。严重肝损害时肝细胞ATP供应减少、线粒体能量代谢异常，导致肝再生受到抑制。补中益气汤为李东垣所创，其具补中益气、升阳举陷之功，有实验证实补中益气汤具有保护线粒体功能、增加线粒体能量代谢的作用，从而促进肝再生。本文综述补中益气汤总方与其中各类中药对线粒体能量代谢的保护作用，从而为促进肝再生提供新的治疗手段并对改善病人预后有重要意义。     

健脾益肝方对非酒精性脂肪性肝病患者脂肪分布及脂代谢的影响

目的:探讨健脾益肝方对非酒精性脂肪性肝病(NAFLD)患者脂肪分布及脂代谢的影响。方法:将80例NAFLD患者随机分为对照组和治疗组各40例。两组患者均在多学科联合管理下给予个体化的饮食、运动等生活方式指导,治疗组患者在此基础上加用健脾益肝方,疗程均为3个月。通过生物电阻抗技术测量患者治疗前后脂肪质量及分布,定期监测肝肾功能、血脂指标。比较两组患者肥胖、脂肪分布、血脂指标变化。结果:治疗组患者有效率为97.5%,明显高于对照组的82.5%,差异有统计学意义(P<0.05);治疗组患者BMI、BFP、WHR、TC、TG及LDL-C水平明显低于对照组,差异有统计学意义(均P<0.05);治疗组患者躯干及内脏脂肪沉积改善明显优于对照组,差异有统计学意义(均P<0.05)。结论:生活方式干预联合健脾益肝方治疗NAFLD患者能显著改善患者的肥胖及脂代谢紊乱,并且与躯干和内脏脂肪质量的下降密切相关。     

茯苓多糖对ApoE-/-AS小鼠肝脏脂质沉积及胆固醇逆向转运相关蛋白表达的影响＊

目的 探讨茯苓多糖对载脂蛋白E基因敲除（ApoE^-/-）动脉粥样硬化（Atherosclerosis，AS）小鼠肝脏脂质沉积及胆固醇逆向转运的影响。方法 采用随机数字表法将30只ApoE^-/-小鼠随机分为模型组、茯苓多糖组、辛伐他汀组，每组10只，10只C57BL/6J小鼠作为正常组。正常组给予基础饲料喂饲，其余小鼠给予高脂饲料喂饲12周。茯苓多糖组以0.2 g/kg/d灌胃，辛伐他汀组以2.275 mg/kg/天灌胃，正常组和模型组给予等体积生理盐水灌胃，共干预4周。全自动生化分析仪检测小鼠血清三酰甘油（TG）、总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）水平，苏木素-伊红（HE）染色观察小鼠肝脏病理形态学变化，油红O染色观察小鼠肝脏脂质沉积情况，ELISA检测各组小鼠血清载脂蛋白A1 （ApoA1）、对氧磷酶-1（PON1）含量，Real-time RT-qPCR法及Western Blot法检测肝脏胆固醇酯转运蛋白（CETP）、磷脂转运蛋白（PLTP）、卵磷脂胆固醇酰基转移酶（LCAT）mRNA及蛋白表达。结果 与正常组比较，模型组小鼠血清TG、TC、LDL-C含量均明显上升，HDL-C含量明显下降（P<0.01），肝细胞脂肪变性明显，肝脏脂质沉积明显，小鼠血清ApoA1、PON1含量均明显下降（P<0.01），小鼠肝脏CETP、PLTP mRNA及蛋白表达明显上升，LCAT mRNA及蛋白表达明显下降（P<0.01）。与模型组相比，茯苓多糖组血清TG、TC、LDL-C含量均显著下降（P<0.01），HDL-C含量呈上升趋势（P>0.05），肝细胞脂肪变性、脂质沉积程度均有所减轻，茯苓多糖组ApoA1含量明显上升（P<0.01），PON1含量呈上升趋势（P>0.05），茯苓多糖组CETP、PLTP mRNA及蛋白表达有所下降，LCAT mRNA及蛋白表达有所上升（P<0.05，P<0.01）。结论 茯苓多糖可能通过调控血脂水平与胆固醇逆向转运过程，改善ApoE^-/- AS小鼠肝脏脂质沉积，进而发挥防治AS作用。     

癌痛患者的代谢特征与营养治疗对策

癌性疼痛（癌痛）是指肿瘤、肿瘤相关症状或抗肿瘤治疗所致的疼痛，其发生发展与机体营养代谢情况密切相关。 癌痛可从饮食摄入、神经内分泌系统、社会心理等途径影响机体的营养代谢；反过来，机体多种营养物质如维生素类、镁 元素及咖啡因、姜黄素、辣椒素、多不饱和脂肪酸（polyunsaturated fatty acid，PUFA）等的变化亦会通过多种机制对癌 痛产生一定影响 ；另外，肿瘤细胞的异常代谢，如谷氨酸和甲醛含量的增加参与了癌痛的发生发展过程，其中，谷氨酸含量 的升高主要由于肿瘤细胞内氧化 - 还原系统失衡和谷氨酰胺（glutamine， Gln）代谢水平增高所致，进而通过介导瞬时受体电 位阳离子通道亚家族 V 成员 1（transient receptor potential cation channel subfamily V member 1，TRPV1）促使伤害性信号持续性 传导。本文主要对癌痛与营养代谢之间的相互影响以及肿瘤代谢产物引发癌痛的相关机制进行综述，并提出了针对癌痛患者 的营养治疗对策。