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Genome-Wide Association Study of Cryptosporidiosis in Infants Implicates PRKCA.

婴儿隐孢子虫病的全基因组关联研究提示 PRKCA。

  • 影响因子:6.74700
  • DOI:10.1128/mBio.03343-19
  • 作者列表:"Wojcik GL","Korpe P","Marie C","Mentzer AJ","Carstensen T","Mychaleckyj J","Kirkpatrick BD","Rich SS","Concannon P","Faruque ASG","Haque R","Petri WA Jr","Duggal P
  • 发表时间:2020-02-04

Diarrhea is a major cause of both morbidity and mortality worldwide, especially among young children. Cryptosporidiosis is a leading cause of diarrhea in children, particularly in South Asia and sub-Saharan Africa, where it is responsible for over 200,000 deaths per year. Beyond the initial clinical presentation of diarrhea, it is associated with long-term sequelae such as malnutrition and neurocognitive developmental deficits. Risk factors include poverty and overcrowding, and yet not all children with these risk factors and exposure are infected, nor do all infected children develop symptomatic disease. One potential risk factor to explain these differences is their human genome. To identify genetic variants associated with symptomatic cryptosporidiosis, we conducted a genome-wide association study (GWAS) examining 6.5 million single nucleotide polymorphisms (SNPs) in 873 children from three independent cohorts in Dhaka, Bangladesh, namely, the Dhaka Birth Cohort (DBC), the Performance of Rotavirus and Oral Polio Vaccines in Developing Countries (PROVIDE) study, and the Cryptosporidiosis Birth Cohort (CBC). Associations were estimated separately for each cohort under an additive model, adjusting for length-for-age Z-score at 12 months of age, the first two principal components to account for population substructure, and genotyping batch. The strongest meta-analytic association was with rs58296998 (P = 3.73 × 10-8), an intronic SNP and expression quantitative trait locus (eQTL) of protein kinase C alpha (PRKCA). Each additional risk allele conferred 2.4 times the odds of Cryptosporidium-associated diarrhea in the first year of life. This genetic association suggests a role for protein kinase C alpha in pediatric cryptosporidiosis and warrants further investigation.IMPORTANCE Globally, diarrhea remains one of the major causes of pediatric morbidity and mortality. The initial symptoms of diarrhea can often lead to long-term consequences for the health of young children, such as malnutrition and neurocognitive developmental deficits. Despite many children having similar exposures to infectious causes of diarrhea, not all develop symptomatic disease, indicating a possible role for human genetic variation. Here, we conducted a genetic study of susceptibility to symptomatic disease associated with Cryptosporidium infection (a leading cause of diarrhea) in three independent cohorts of infants from Dhaka, Bangladesh. We identified a genetic variant within protein kinase C alpha (PRKCA) associated with higher risk of cryptosporidiosis in the first year of life. These results indicate a role for human genetics in susceptibility to cryptosporidiosis and warrant further research to elucidate the mechanism.


腹泻是全世界发病率和死亡率的主要原因,尤其是在幼儿中。隐孢子虫病是儿童腹泻的主要原因,特别是在南亚和撒哈拉以南非洲,每年有超过 200,000 人死于隐孢子虫病。除了腹泻的最初临床表现外,它还与营养不良和神经认知发育缺陷等长期后遗症有关。危险因素包括贫困和过度拥挤,但并非所有具有这些危险因素和暴露的儿童都被感染,也不是所有被感染的儿童都发展为症状性疾病。解释这些差异的一个潜在风险因素是它们的人类基因组。为了确定与症状性隐孢子虫病相关的遗传变异,我们进行了一项全基因组关联研究 (GWAS),检查了孟加拉国达卡三个独立队列的 650万名儿童的 873 个单核苷酸多态性 (SNPs)。即达卡出生队列 (DBC),轮状病毒和口服脊髓灰质炎疫苗在发展中国家的表现(提供) 研究,以及隐孢子虫病出生队列 (CBC)。在相加模型下分别估计每个队列的关联,调整 12 个月时的长度-年龄 Z 评分,前两个主成分解释群体亚结构, 和基因分型批次。最强的 meta 分析关联是与蛋白激酶 C α (PRKCA) 的内含子 SNP 和表达数量性状位点 (eQTL) rs58296998 (p = 3.73 × 10-8)。每个额外的风险等位基因赋予生命第一年隐孢子虫相关性腹泻的几率 2.4 倍。这种遗传关联表明蛋白激酶 C α 在儿童隐孢子虫病中的作用,值得进一步研究。重要性在全球范围内,腹泻仍然是儿童发病和死亡的主要原因之一。腹泻的最初症状往往会导致幼儿健康的长期后果,如营养不良和神经认知发育缺陷。尽管许多儿童对腹泻的感染性原因有类似的暴露,但并非所有人都发展为症状性疾病,表明人类遗传变异可能起作用。在此,我们在来自孟加拉国达卡的三个独立队列婴儿中进行了一项与隐孢子虫感染 (腹泻的主要原因) 相关的症状性疾病易感性的遗传学研究。我们在蛋白激酶 C α (PRKCA) 内发现了一个与出生后第一年隐孢子虫病高风险相关的基因变异。这些结果表明人类遗传学在隐孢子虫病易感性中的作用,并值得进一步研究以阐明其机制。



作者列表:["Kuehl CJ","D'Gama JD","Warr AR","Waldor MK"]

METHODS:Shigella species cause diarrheal disease globally. Shigellosis is typically characterized by bloody stools and colitis with mucosal damage and is the leading bacterial cause of diarrheal death worldwide. After the pathogen is orally ingested, it invades and replicates within the colonic epithelium through mechanisms that rely on its type III secretion system (T3SS). Currently, oral infection-based small animal models to study the pathogenesis of shigellosis are lacking. Here, we found that orogastric inoculation of infant rabbits with Shigella flexneri resulted in diarrhea and colonic pathology resembling that found in human shigellosis. Fasting animals prior to S. flexneri inoculation increased the frequency of disease. The pathogen colonized the colon, where both luminal and intraepithelial foci were observed. The intraepithelial foci likely arise through S. flexneri spreading from cell to cell. Robust S. flexneri intestinal colonization, invasion of the colonic epithelium, and epithelial sloughing all required the T3SS as well as IcsA, a factor required for bacterial spreading and adhesion in vitro Expression of the proinflammatory chemokine interleukin 8 (IL-8), detected with in situ mRNA labeling, was higher in animals infected with wild-type S. flexneri versus mutant strains deficient in icsA or T3SS, suggesting that epithelial invasion promotes expression of this chemokine. Collectively, our findings suggest that oral infection of infant rabbits offers a useful experimental model for studies of the pathogenesis of shigellosis and for testing of new therapeutics.IMPORTANCEShigella species are the leading bacterial cause of diarrheal death globally. The pathogen causes bacillary dysentery, a bloody diarrheal disease characterized by damage to the colonic mucosa and is usually spread through the fecal-oral route. Small animal models of shigellosis that rely on the oral route of infection are lacking. Here, we found that orogastric inoculation of infant rabbits with S. flexneri led to a diarrheal disease and colonic pathology reminiscent of human shigellosis. Diarrhea, intestinal colonization, and pathology in this model were dependent on the S. flexneri type III secretion system and IcsA, canonical Shigella virulence factors. Thus, oral infection of infant rabbits offers a feasible model to study the pathogenesis of shigellosis and to develop and test new therapeutics.

作者列表:["Willowson KP","Schembri GP","Bernard EJ","Chan DL","Bailey DL"]

METHODS:PURPOSE:To quantify the effects of absorbed radiation dose on healthy liver parenchyma following radioembolisation (RE) using [99mTc]TcMebrofenin to analyse both global and regional liver function. METHODS:Patients having RE to treat hepatic disease underwent a [99mTc]TcMebrofenin hepatobilliary scintigraphy (HBS) study at both baseline and 8 weeks following treatment. Changes in global liver uptake rate were compared with healthy liver absorbed dose measures derived from the post-treatment 90Y PET/CT, including average dose, minimum dose to 70% of the volume (D70) and volume receiving at least 50 Gy (V50). Changes in functional burden associated with treatment and spared liver volumes in patients receiving lobar RE were also assessed, as were changes experienced by regional volumes corresponding to various dose ranges. Standard liver function pathology tests (LFTs) (bilirubin, albumin, ALP, AST, ALT and GGT) were examined for changes between baseline and post-treatment. RESULTS:Thirty-five patients were included in the study, of which, 9 had lobar treatment. A significant linear correlation was found between both baseline global liver uptake rate (negative) and D70 with change in global liver uptake rate. Patients undergoing lobar treatments demonstrated a shift in functional burden, and a significant difference was seen between the mean dose corresponding to liver volumes that increased their functional burden (9 Gy) and those that decreased their functional burden (35 Gy). No baseline LFTs predicted a decrease in global liver function; however, D70 demonstrated a linear correlation with changes in bilirubin and GGT. CONCLUSIONS:Given the significant negative relationship between baseline and change in global liver uptake rate, baseline HBS studies should not be used alone to disqualify patients considered for RE. In terms of treatment planning and evaluation, D70 may be the most appropriate metric of dose, with values greater than 15 Gy indicative of a likely drop in global liver function. The evidence of increasing functional burden in spared liver volumes suggests that patients at risk of complications could benefit from a lobar approach to treatment.

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作者列表:["Fan M","Xiang G","Chen J","Gao J","Xue W","Wang Y","Li W","Zhou L","Jiao R","Shen Y","Xu Q"]

METHODS:NLRP3 inflammasome may serve as a potential target for the development of novel therapeutics for inflammatory bowel diseases. In this study, we found that Libertellenone M (Lib M), a secondary metabolite from the endophytic fungus Phomopsis sp. S12, has anti-inflammatory potential both in vitro and in vivo. Lib M selectively inhibited the expression of proinflammatory cytokine IL-1β and IL-18 in LPS-activated macrophages. The cleavage of pro-caspase 1 was remarkably reduced by Lib M in macrophages stimulated with three NLRP3 inflammasome activators. Administering Lib M attenuated dextran sulfate sodium-induced experimental acute colitis in mice and significantly reduced the production of these cytokines and cleaved caspase 1 in colon tissues. Apart from inhibition of NLRP3 inflammasome assembly, Lib M also suppressed NF-κB nuclear translocation in macrophages. Taken together, these findings suggest that Lib M-mediated inhibition of NLRP3 inflammasome activation could protect against colitis-like inflammatory diseases, and that this compound derived from a plant-associated fungus might inspire the exploration of novel immunosuppressive agents.

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