Photoperiodic gene expression of insulin receptor is associated with diapause regulation in silkworm

Bivoltine silkworms (Bombyx mori) are destined to respectively produce diapause or non-diapause eggs when they are reared under short or long days during the larval stage. The insulin signaling pathway is thought to play an essential role in regulating diapause in various insect species, but its involvement in silkworm diapause programming has not been investigated in detail. Therefore, we examined day-night expression of the insulin receptor (InR) gene in the silkworm larval brain under different photoperiods or in night interruption experiments in which larvae were exposed to light for 2 h during the nighttime of short days. Expression of the InR gene was photoperiod-dependent and InR mRNA levels decreased with increasing daylength. As the daylength increased, expression during the nighttime decreased to lower stable levels earlier than that during the daytime. During night interruptions that induced non-diapause, the nighttime expression of InR decreased to low levels like those during long days, although daytime expression was only moderately decreased. Nighttime InR expression was downregulated in silkworms reared under non-diapause-inducing conditions (long days and night interruptions). In contrast, abundant InR was expressed during the day and night in short days that induced diapause. Our findings suggested that InR expression in the larval brain is associated with programming the diapause status in the next generation of silkworms. Downregulated InR might suppress the insulin signaling pathway and cause non-diapause induction in the next generation. DOI: http://dx.doi.org/10.5281/zenodo.1041315

Silkworm larvae (Bombyx mori) can learn cues associated with finding food

The present study investigated the ability of silkworm Bombyx mori (Lepidoptera: Bombycidae) larvae to learn. Silkworm larvae were trained to consume food that was placed on red paper; consequently they became attracted to red, rather than blue paper even in the absence of food. In contrast, untrained controls had no preference for either red or blue paper. These results suggested that silkworm larvae learned to associate red paper with food, and that they can discriminate colors. DOI: http://dx.doi.org/10.5281/zenodo.560946

DOCK2 is involved in the host genetics and biology of severe COVID-19

「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target

The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection