Melatonin inhibits osteoclastogenesis via RANKL/OPG suppression mediated by Rev‐Erbα in osteoblasts

Diabetic osteoporosis is secondary osteoporosis and a serious complication of diabetes with a high incidence rate and poor prognosis. The specific mechanism of diabetic osteoporosis is unclear, and prevention and treatment options are limited. Recently, melatonin has been found to prevent and treat diabetic osteoporosis. Herein, we investigated the mechanism whereby melatonin inhibits osteoclastogenesis and identified a new target for osteoporosis treatment. We established an in vitro osteoblast–osteoclast co‐culture system as a diabetic osteoporosis model. Osteoclastogenesis was determined using tartrate‐resistant acid phosphatase staining and cathepsin K expression. Real‐time PCR was used to ascertain expression of microRNA mir‐882, targeting Rev‐Erbα. Western blotting was performed to detect the expression of Rev‐Erbα, receptor activator of NF‐kB ligand (RANKL), and osteoprotegerin (OPG), and ELISA was utilized to analyse the secreted form of RANKL. High glucose promoted osteoclastogenesis and elevated the RANKL/OPG ratio in osteoblasts, while melatonin reversed these effects. High glucose inhibited Rev‐Erbα expression, while melatonin promoted its expression. Conversely, high glucose promoted mir‐882 expression, while melatonin inhibited it. We infer that melatonin inhibits RANKL expression in osteoblasts via the mir‐882/Rev‐Erbα axis, thus inhibiting osteoclastogenesis. Our findings provide insights into diabetic osteoporosis and identify a new therapeutic target for osteoporosis.     

重庆酸雨区马尾松林凋落物特征及对干旱胁迫的响应

气候变化导致干旱等极端气象事件增多,这将和酸雨等环境胁迫一起影响森林健康.在重庆铁山坪于2010年监测了酸雨区受害马尾松林的凋落物数量和组分特征及其对土壤水分的响应.结果表明:马尾松林月凋落物量呈“双峰”模式,第1高峰出现在8-9月份伏旱期,第2高峰出现在冬季休眠的12月份;枯死针叶占年凋落物总量的48.42％,凋落物组分比例为针叶＞树枝＞阔叶＞有机碎屑＞树皮及球果;除阔叶凋落物外,其它组分凋落物在伏旱期均明显增加,与土壤湿度显著负相关,特别是30-40 cm和40-50 cm土层;此外,马尾松林凋落物量还与表征气象干旱的气象指标显著相关.和健康森林相比,酸雨区受害林木的细根数量变少和分布变浅导致马尾松林针叶的年形成量与凋落量减少,但枝凋落量及其占总凋落量的比例增大;凋落发生对于旱胁迫更加敏感,年凋落物量的时间分布更集中在伏旱期;酸雨和干旱的双重胁迫将进一步恶化研究地区的森林健康状况.     

Evaluation of immunogenicity and protective efficacy against Mycobacterium tuberculosis infection elicited by recombinant Mycobacterium bovis BCG expressing human Interleukin-12p70 and Early Secretory Antigen Target-6 fusion protein

ESAT-6 protein of Mycobacterium tuberculosis is absent in Mycobacterium bovis BCG and Mycobacterium microti and has been demonstrated to stimulate strong cell-mediated immunity. IL-12 can play crucial roles in regulating IFN-γ production and Th1 effectors production. In this study, we constructed three rBCG vaccines that could express proteins of human IL-12p70 and/or ESAT-6 and evaluated their immunogenicity and protective efficacy in mice. Our experiments illustrated that the rBCG-IE (expressing a fusion protein of human IL-12p70 and ESAT-6) was capable of inducing stronger Th1 type cell-mediated immune responses than conventional BCG, or rBCG-I (expressing human IL-12p70), or rBCG-E (expressing ESAT-6). However, the results of protective experiments showed that rBCG-IE could only confer similar and even lower protective efficacy against M. tuberculosis H37Rv infection compared with BCG vaccine.     

坡向尺度差异对大理苍山捕食线虫真菌分布格局的影响

为了解大理苍山地区不同尺度坡向上捕食线虫真菌的分布格局及其驱动因素,利用系统采样法对大理苍山东、西坡及其次级南、北坡的捕食线虫真菌进行调查。按照五点采样法采集苍山东、西坡及其次级南、北坡土壤样品共300份。采用传统方法对捕食线虫真菌进行分离纯化,结合形态特征和分子生物学方法鉴定所得菌株,按照新分类系统进行分类,鉴定为3属12种57株捕食线虫真菌。结果表明：苍山各尺度坡向捕食线虫真菌检出率和多样性指数均是西坡大于东坡,次级南坡大于次级北坡。次级南、北坡向间捕食线虫真菌群落差异大于东、西坡向间;西坡次级南、北坡向间的群落差异最大;东、西坡向的次级南坡向间群落差异也较大;东坡次级北坡与西坡次级北坡间的群落最为相似。产黏性菌网的Arthrobotrys属、产黏性球和黏性分枝的Dactylellina属在东、西坡及其次级南、北坡间均有分布,而产收缩环的Drechslerella属仅在西坡有分布。因此,坡向是影响苍山捕食线虫真菌空间分布格局的驱动因子之一,不同尺度坡向上捕食线虫真菌分布格局存在差异;次级南、北坡间捕食线虫真菌群落差异性比东、西坡间大,小尺度坡向间地理屏障对捕食线虫真菌分布格局的影响大于大尺度坡向间环境异质性的作用;环境筛选和扩散限制均会影响到捕食线虫真菌的群落构建过程。     

基于大型底栖动物完整性指数的伊犁河健康评价及其对时间尺度变化的响应

大型底栖动物完整性指数（Benthic index of biotic integrity, B-IBI）是广泛应用的河流生态健康评价方法,然而从时间尺度（月份、年际变化）上评价B-IBI适用性的研究较少。有鉴于此,于2013-2015年期间,每年在5月、7月、8月和10月分别对新疆伊犁河大型底栖动物群落结构进行系统调查,并构建底栖动物完整性指数,评价河流水体的健康状况,同时评价其在时间尺度上的影响。非度量多维尺度分析（Non-metric multidimensional scaling, NMDS）显示,伊犁河不同月份的大型底栖动物群落结构相似度较高。通过对群落丰富度、种类个体相对丰度、功能摄食群、耐污能力、小生境质量和生物多样性指数等6个大类共计30个候选参数进行筛选,选取EPT（蜉蝣目、襀翅目、毛翅目）分类单元数、蜉蝣目个体相对丰度、耐污类群的个体相对丰度、生物指数（Biotic index, BI）以及黏附者个体相对丰度为伊犁河流域B-IBI健康评价体系的核心指标。B-IBI的评价等级为：B-IBI>3.38为健康,2.53-3.38为亚健康,1.69-2.53为一般,0.84-1.69为差,B-IBI值≤0.84为极差。结果显示,伊犁河8个典型样点中,6个采样点健康状况为健康或者亚健康,2个采样点为一般。总体上伊犁河健康状况较好,其中支流巩乃斯河和喀什河的健康状况要好于伊犁河干流和支流特克斯河。不同月份的B-IBI值无显著性差异（P>0.05）,表明伊犁河流域整体健康状况不受季节变化的重要影响。2013年与2015年B-IBI值差异显著（P<0.05）,伊犁河健康状况存在逐年变好的趋势,河流的生物健康评价需要开展长期的监测才能较全面的反映河流健康状况。参照点整体上的B-IBI值显著高于受损点的B-IBI值,表明B-IBI健康评价体系在伊犁河流域的良好适用性。该研究将从时间尺度上为基于B-IBI的河流健康评价方法提供理论参考。     

重庆铁山坪马尾松天然次生林降雨截持与贮水特征

马尾松林是三峡库区防护林体系中最重要的森林类型,然而以往对结构更为复杂的马尾松天然次生林的生态水文效应研究还很不足,限制着全面了解和准确评价库区森林发挥的涵养水源服务功能。以重庆铁山坪的马尾松天然次生林为对象,采用定位监测结合室内测定的实验方法,系统研究了林冠层、林下草本层、枯落物层、土壤层的水文特征。结果表明：（1）2010-2011年马尾林穿透雨量、干流量、林冠截留量分别占总降雨量（1972.39 mm）的84.66%、0.26%和15.07%,且均与次降雨量呈显著正相关（P<0.01）,其中干流在次降雨量达到5 mm时产生;林冠截留量随次降雨量增大而逐渐达到饱和（6 mm左右）。（2）林下草本植物的地上生物量达1.32 t/hm²,其持水率随浸水时间呈对数函数增加（P<0.01）,最大持水量为0.61 mm。（3）枯落物贮存量达10.74 t/hm²,未分解、半分解、未分解与半分解混合枯落物的最大持水率为183.76%、206.31%和197.62%,未分解与半分解层枯落物的最大持水能力达1.44 mm。（4）0-80 cm土层的饱和贮水量达334.75 mm,其中滞留贮水量达49.08 mm,占饱和贮水量14.66%。马尾松天然次生林各作用层的降雨截持及贮水作用明显,其中尤以土壤层贮水能力最强。研究结果可为三峡库区森林涵养水源服务功能模拟与评价提供重要参考依据。     

三峡消落带不同坡度狗牙根及实生土壤生态化学计量特征

三峡库区消落带反季节水位波动驱使下植物的养分适应策略和内稳态特征研究对消落带植被恢复及生态功能调控有重要意义。然而,三峡消落带范围广、地形复杂,不同生境下植物适应特征仍存在不确定性。本研究以三峡消落带广泛分布的优势植物狗牙根为研究对象,选取28个地形差异较大的样地进行采样分析,重点探讨不同坡度（0-5°、5-10°、10-15°、15-20°、>20°）狗牙根及其实生土壤生态化学计量特征的变异关系,揭示坡度对狗牙根养分适应及内稳态的影响机制。结果表明：（1）坡度对狗牙根实生土壤的养分及化学计量特征具有显著影响,土壤有机碳（SOC）、全氮（STN）、速效氮（SAN）、全磷（STP）、速效磷（SAP）含量均随坡度增加而降低,<10°的缓坡消落带土壤养分显著高于10°以上的样地;土壤碳氮比（C ∶ N）、碳磷比（C ∶ P）均随坡度增加而降低,而氮磷比（N ∶ P）比相对稳定,表明坡度增大,土壤营养物的流失具有同步性,且流失速度较有机碳慢;（2）随坡度增加,狗牙根各营养器官C含量呈增加趋势,而氮（N）、磷（P）则呈降低趋势,且坡度变化改变了狗牙根各营养器官间的养分分配;植物根、茎C ∶ N、C ∶ P随坡度增加而增加,N ∶ P随坡度增加而降低,而叶片均没有明显变化,表明在坡度改变了土壤养分供应水平的情况下,狗牙根优先稳定其叶片化学计量比以提高适应能力;（3）坡度与土壤中SOC、STN、SAN含量呈现显著负相关,而土壤STN与狗牙根植物养分及化学计量特征均有显著相关关系,由此可见,坡度变化导致土壤氮素流失增加是影响狗牙根生态化学计量特征分异的主要机制;（4）狗牙根与实生土壤的碳氮磷元素内稳性整体表现为C>P>N,化学计量比内稳性表现为C ∶ P>C ∶ N>N ∶ P,随着坡度增加,狗牙根N、P的内稳性呈增强趋势,而C ∶ N、N ∶ P呈显著降低,表明坡度变化导致狗牙根形成了不同的适生策略。研究表明,在三峡库区复杂的地形条件下,狗牙根能有效维持体内化学计量平衡以响应不同的坡度条件,并且内稳性较好,是三峡库区消落带植被恢复与保护的优势植物物种。     

四十里湾营养状况与浮游植物生态特征

研究了2006-2010年5月、8月和10月四十里湾的营养盐结构、海水营养级、有机污染状况、浮游植物数量及多样性变化特征,并对上述因子进行了相关性分析.结果表明,近5年N/P值先增加后降低,5月和8月海水多为贫营养和磷限制中度营养,而10月多呈磷限制潜在性富营养;除2006年和2007年10月水质分别达到轻度和中度污染外,其他时期基本未受有机污染,四十里湾有机污染状况有向好趋势.浮游植物多样性指数年际变化显示,总体呈先降低后增加的趋势,与其数量变化趋势相反.相关性分析显示,有机污染指数A与无机磷(IP)浓度呈显著正相关(P＜0.01),与DIN相关不显著(P＞0.05),这说明IP是影响四十里湾有机污染水平的首要因素;浮游植物多样性指数与其数量呈负相关,而与Si/P和IP浓度分别呈正相关(P＞0.05),浮游植物多样性指数与Si/P和IP的Pearson相关系数分别达到0.446和0.413.IP是四十里湾海水营养状况、有机污染及浮游植物多样性的主要影响因子之一.     

Colorectal cancer cell intrinsic fibroblast activation protein alpha binds to Enolase1 and activates NF-κB pathway to promote metastasis

Fibroblast activation protein alpha (FAP) is a marker of cancer-associated fibroblast, which is also expressed in cancer epithelial cells. However, the role of FAP in colorectal cancer (CRC) cells remains to be elucidated. Here we investigate the expression pattern of FAP in CRC tissues and cells to prove that FAP is upregulated in CRC cells. Loss- of and gain-of-function assays identified FAP promotes migration and invasion instead of an effect on cell proliferation. Microarray assays are adopted to identify the different expressed genes after FAP knockdown and gene set enrichment analysis (GSEA) is used to exploit the involved signaling pathway. Our works reveal FAP exerts a function dependent on NF-κB signaling pathway and FAP expression is associated with NF-κB signaling pathway in clinical samples. Our work shows FAP is secreted by CRC cells and soluble FAP could promote metastasis. To investigate the mechanism of FAP influencing the NF-κB signaling pathway, LC/MS is performed to identify the proteins interacting with FAP. We find that FAP binds to ENO1 and activates NF-κB signaling pathway dependent on ENO1. Blocking ENO1 could partially reverse the pro-metastatic effect mediated by FAP. We also provide evidences that both FAP and ENO1 are associated with CRC stages, and high levels of FAP and ENO1 predict a poor survival in CRC patients. In summary, our work could provide a novel mechanism of FAP in CRC cells and a potential strategy for treatment of metastatic CRC.Subject terms: Cancer immunotherapy, Non-coding RNAs     

A multilevel mixed effects varying coefficient model with multilevel predictors and random effects for modeling hospitalization risk in patients on dialysis

For patients on dialysis, hospitalizations remain a major risk factor for mortality and morbidity. We use data from a large national database, United States Renal Data System, to model time-varying effects of hospitalization risk factors as functions of time since initiation of dialysis. To account for the three-level hierarchical structure in the data where hospitalizations are nested in patients and patients are nested in dialysis facilities, we propose a multilevel mixed effects varying coefficient model (MME-VCM) where multilevel (patient- and facility-level) random effects are used to model the dependence structure of the data. The proposed MME-VCM also includes multilevel covariates, where baseline demographics and comorbidities are among the patient-level factors, and staffing composition and facility size are among the facility-level risk factors. To address the challenge of high-dimensional integrals due to the hierarchical structure of the random effects, we propose a novel two-step approximate EM algorithm based on the fully exponential Laplace approximation. Inference for the varying coefficient functions and variance components is achieved via derivation of the standard errors using score contributions. The finite sample performance of the proposed estimation procedure is studied through simulations.