Understanding host-microbial interactions in rumen：searching the best opportunity for microbiota manipulation

Ruminants utilize a wide variety of dietary substrates that are not digestible by the mammals, through microbial fermentation taking place in the rumen. Recent advanced molecular based approaches have allowed the characterization of rumen microbiota and its compositional changes under various treatment conditions.However, the knowledge is still limited on the impacts of variations in the rumen microbiota on host biology and function. This review summarizes the information to date on host-microbial interactions in the rumen and how we can apply such information to seek the opportunities to enhance the animal performance through manipulating the rumen function.

Intestinal organoid as an in vitro model in studying host-microbial interactions

BACKGROUND： Organoid is an in vitro three-dimensional organ-bud that shows realistic microanatomy and physiological relevance. The progress in generating organoids that faithfully recapitulate human in vivo tissue composition has extended organoid applications from being just a basic research tool to a translational platform with a wide range of uses. Study of host- microbial interactions relies on model systems to mimic the in vivo infection. Researchers have developed various experimental models in vitro and in vivo to examine the dynamic host-microbial interactions. For some infectious pathogens, model systems are lacking whereas some of the used systems are far from optimal. OBJECTIVE： In the present work, we will review the brief history and recent findings using organoids for studying host- microbial interactions. METHODS： A systematic literature search was performed using the PubMed search engine. We also shared our data and research contribution to the field. RESULTS： we summarize the brief history of 3D organoids. We discuss the feasibility of using organoids in studying host- microbial interactions, focusing on the development of intestinal organoids and gastric organoids. We highlight the advantage and challenges of the new experimental models. Further, we discuss the future direction in using organoids in studying host- microbial interactions and its potential application in biomedical studies. CONCLUSION： In combination with genetic, transcriptome and proteomic profiling, both murine- and human-derived organoids have revealed crucial aspects of development, homeostasis and diseases. Specifically, human organoids from susceptible host will be used to test their responses to pathogens, probiotics, and drugs. Organoid system is an exciting tool for studying infectious disease, microbiome, and therapy.

Novel methylxanthine derivative-mediated anti-inflammatory effects in inflammatory bowel disease

Family 18 chitinases have a binding capacity with chitin, a polymer of N-acetylglucosamine. Recent studies strongly suggested that chitinase 3-like 1(CHI3L1, also known as YKL-40) and acidic mammalian chitinase, the two major members of family 18 chitinases, play a pivotal role in the pathogenesis of inflammatory bowel disease(IBD), bronchial asthma and several other inflammatory disorders. Based on the data from highthroughput screening, it has been found that three methylxanthine derivatives, caffeine, theophylline, and pentoxifylline, have competitive inhibitory effects against a fungal family 18 chitinase by specifically interacting with conserved tryptophans in the active site of this protein. Methylxanthine derivatives are also known as adenosine receptor antagonists, phosphodiesterase inhibitors and histone deacetylase inducers. Anti-in-flammatory effects of methylxanthine derivatives have been well-documented in the literature. For example, a beneficial link between coffee or caffeine consumption and type 2 diabetes as well as liver cirrhosis has been reported. Furthermore, theophylline has a long history of being used as a bronchodilator in asthma therapy, and pentoxifylline has an immuno-modulating effect for peripheral vascular disease. However, it is still largely unknown whether these methylxanthine derivativemediated anti-inflammatory effects are associated with the inhibition of CHI3L1-induced cytoplasmic signaling cascades in epithelial cells. In this review article we will examine the above possibility and summarize the biological significance of methylxanthine derivatives in intestinal epithelial cells. We hope that this study will provide a rationale for the development of methylxanthine derivatives, in particular caffeine,-based antiinflammatory therapeutics in the field of IBD and IBDassociated carcinogenesis.

Both host and diet shape bacterial communities of predatory mites

Microbial communities,derived from food,ambient,and inner,can affect host ecological adaption and evolution.Comparing with most phytophagous arthropods,predators may have more opportunities to develop specific microbiota depending on the level of prey specialization.To explore how diet sources affect host microbial communities and vary across predator species,we considered 3 types of predators from Phytoseiidae(Acari:Mesostigmata):polyphagous(Amblyseius orientalis Ehara,Neoseiulus barkeri Hughes,and Amblyseius swirski Athias-Henrio),oligophagous(Neoseiulus californicus McGregor),and monophagous(Phytoseiulus persimilis Athias-Henriot)predatory mites.The polyphagous species were fed on 2 types of diets,natural prey and alternative prey.By using 16S rRNA sequencing,we found that diet was the main source of microbiota in predatory mites,while there was no clear pattern affected by prey specialization.Among 3 polyphagous predators,host species had a larger impact than prey on microbial composition.Unlike A.orientalis or N.barkeri which showed consistency in their microbiota,prey switching significantly affectedβ-diversity of bacterial composition in A.swirskii,with 56%of the microbial alteration.In short,our results confirmed the substantial influence of diet on host microbial construction in predatory species,and highlighted species differences in shaping the microbiota which are not necessarily related to prey specialization.