Dissecting mechanisms of fecal microbiota transplantation efficacy in disease.

Fecal microbiota transplantation (FMT) has emerged as an alternative or adjunct experimental therapy for microbiome-associated diseases following its success in the treatment of recurrent Clostridioides difficile infections (rCDIs). However, the mechanisms of action involved remain relatively unknown. The term 'dysbiosis' has been used to describe microbial imbalances in relation to disease, but this traditional definition fails to consider the complex cross-feeding networks that define the stability of the microbiome. Emerging research transitions toward the targeted restoration of microbial functional networks in treating different diseases. In this review, we explore potential mechanisms responsible for the efficacy of FMT and future therapeutic applications, while revisiting definitions of 'dysbiosis' in favor of functional network restoration in rCDI, inflammatory bowel diseases (IBDs), metabolic diseases, and cancer.

DnaJC7 in Amyotrophic Lateral Sclerosis.

Protein misfolding is a common basis of many neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Misfolded proteins, such as TDP-43, FUS, Matrin3, and SOD1, mislocalize and form the hallmark cytoplasmic and nuclear inclusions in neurons of ALS patients. Cellular protein quality control prevents protein misfolding under normal conditions and, particularly, when cells experience protein folding stress due to the fact of increased levels of reactive oxygen species, genetic mutations, or aging. Molecular chaperones can prevent protein misfolding, refold misfolded proteins, or triage misfolded proteins for degradation by the ubiquitin-proteasome system or autophagy. DnaJC7 is an evolutionarily conserved molecular chaperone that contains both a J-domain for the interaction with Hsp70s and tetratricopeptide domains for interaction with Hsp90, thus joining these two major chaperones' machines. Genetic analyses reveal that pathogenic variants in the gene encoding DnaJC7 cause familial and sporadic ALS. Yet, the underlying ALS-associated molecular pathophysiology and many basic features of DnaJC7 function remain largely unexplored. Here, we review aspects of DnaJC7 expression, interaction, and function to propose a loss-of-function mechanism by which pathogenic variants in DNAJC7 contribute to defects in DnaJC7-mediated chaperoning that might ultimately contribute to neurodegeneration in ALS.