Alzheimer’s disease (AD) is a progressive neurodegenerative disease associated with a complex genetic etiology. Besides the apolipoprotein E ε4 (APOE ε4) allele, a few dozen other genetic loci associated with AD have been identified through genome-wide association studies (GWAS) conducted mainly in individuals of European ancestry. Recently, several GWAS performed in other ethnic groups have shown the importance of replicating studies that identify previously established risk loci and searching for novel risk loci. APOE-stratified GWAS have yielded novel AD risk loci that might be masked by, or be dependent on, APOE alleles. We performed whole-genome sequencing (WGS) on DNA from blood samples of 331 AD patients and 169 elderly controls of Korean ethnicity who were APOE ε4 carriers. Based on WGS data, we designed a customized AD chip (cAD chip) for further analysis on an independent set of 543 AD patients and 894 elderly controls of the same ethnicity, regardless of their APOE ε4 allele status. Combined analysis of WGS and cAD chip data revealed that SNPs rs1890078 (P = 6.64E−07) and rs12594991 (P = 2.03E−07) in SORCS1 and CHD2 genes, respectively, are novel genetic variants among APOE ε4 carriers in the Korean population. In addition, nine possible novel variants that were rare in individuals of European ancestry but common in East Asia were identified. This study demonstrates that APOE-stratified analysis is important for understanding the genetic background of AD in different populations.

In recent years, there has been a rapid increase in microbiome studies to explore microbial alterations causing disease status and unveil disease pathogenesis derived from microbiome environmental modifications. Convincing evidence of lung microbial changes involving asthma has been collected; however, whether lung microbial changes under obesity leads to severe asthma in a state of allergen exposure has not been studied sufficiently. Here, we measured bacterial alterations in the lung of an allergen mouse model induced by a high fat diet (HFD) by using 16S rRNA gene sequencing. A total of 33 pathogen‑free 3‑week‑old male C57BL/6 mice were used, and they divided randomly into two groups. The Chow diet (n = 16) and high fat diet (n = 17) was administrated for 70 days. Mice were sensitized with PBS or Dermatophagoides pteronyssinus extract (Der.p), and concentration levels of total IgE and Der.p-IgE in the blood were measured to quantify immune responses. Although there were no meaningful differences in bacterial species richness in the HFD mouse group, momentous changes of bacterial diversity in the HFD mouse group were identified after the mouse group was exposed to allergens. At a genus level, the fluctuations of taxonomic relative abundances in several bacteria such as Ralstonia, Lactobacillus, Bradyrhizobium, Gaiella, PAC001932_g, Pseudolabrys, and Staphylococcus were conspicuously observed in the HFD mouse group exposed to allergens. Also, we predicted metabolic signatures occurring under microbial alterations in the Chow group versus the Chow group exposed to allergens, as well as in the HFD mouse group versus the HFD group exposed to allergens. We then compared their similarities and differences. Metabolic functions associated with macrophages such as propanoate metabolism, butanoate metabolism, and glycine-serine-threonine metabolism were identified in the HFD group versus the Chow group. These results provide new insights into the understanding of a microbiome community of obese allergic asthma, and shed light on the functional roles of lung microbiota inducing the pathogenesis of severe asthma.

The influences of diet and environmental factors on gut microbial profiles have been widely acknowledged; however, the specific roles of host genetics remain uncertain. To unravel host genetic effects, we raised 47 Jeju crossbred (Jeju × Thoroughbred) foals that exhibited higher genetic diversity. Foals were raised under identical environmental conditions and diets. Microbial composition revealed that Firmicutes, Bacteroidetes, and Spirochaetes were the predominant phyla. We identified 31 host–microbiome associations by utilizing 47,668 single nucleotide polymorphisms (SNPs) and 734 taxa with quantitative trait locus (QTL) information related to horse growth. The taxa involved in 31 host–microbiome associations were functionally linked to carbohydrate metabolism, energy metabolic processes, short-chain fatty acid (SCFA) production, and lactic acid production. Abundances of these taxa were affected by specific SNP genotypes. Most growth-associated SNPs are found between genes. The rs69057439 and rs69127732 SNPs are located within the introns of the VWA8 and MFSD6 genes, respectively. These genes are known to affect energy balance and metabolism. These discoveries emphasize the significant effect of host SNPs on the development of the intestinal microbiome during the initial phases of life and provide insights into the influence of gut microbial composition on horse growth.