McMurtry V.E.,Louisiana State University Health Sciences Center |
Gupta R.W.,Childrens Hospital |
Tran L.,Pediatrix Medical Group of Louisiana |
Blanchard E.E.,Louisiana State University Health Sciences Center |
And 4 more authors.
Microbiome | Year: 2015
Background: Necrotizing enterocolitis (NEC) is a devastating neonatal gastrointestinal disease that primarily affects premature infants. It is characterized by bowel inflammation and necrosis. In spite of extensive research, there has been little progress in decreasing the incidence or mortality of NEC over the past three decades. The exact etiology of NEC has not been identified. However, it is believed to result from an inappropriate immune response to gut microbiota. Using 454-pyrosequencing analyses of 16S rRNA genes that were PCR-amplified from stool DNA specimens, we compared the gut microbiota of infants with NEC to matched controls without NEC. The infants with NEC were then categorized into three subgroups based on severity: mild, severe, and lethal. We compared the microbiota among these subgroups and between each severity group and appropriate controls. Results: Bacterial diversity and the relative abundance of Actinobacteria and Clostridia were significantly lower in NEC specimens compared to controls. The absence of Clostridia was significantly associated with NEC. Microbial diversity and Clostridia abundance and prevalence decreased with increasing severity of NEC. Conclusions: Low bacterial diversity in stool specimens may be indicative of NEC and the severity of NEC. The low bacterial diversity, and the lack of Clostridia in lethal specimens, could indicate that the presence of a diverse bacterial population in the gut as well as the presence of taxa such as Clostridia may play a role in attenuating inflammation leading to NEC. © 2015 McMurtry et al.; licensee BioMed Central.
PubMed | The Research Institute for Children
Type: Journal Article | Journal: Medical mycology | Year: 2011
Intracellular transport is an essential biological process that is highly conserved throughout the eukaryotic organisms. In fungi, adaptor proteins implicated in the endocytic cycle of endocytosis and exocytosis were found to be important for growth, differentiation, and/or virulence. For example, Saccharomyces cerevisiae Pan1 is an endocytic protein that regulates membrane trafficking, the actin cytoskeleton, and signaling. In Cryptococcus neoformans, a multi-modular endocytic protein, Cin1, was recently found to have pleiotropic functions in morphogenesis, endocytosis, exocytosis, and virulence. Interestingly, Cin1 is homologous to human intersectin ITSN1, but homologs of Cin1/ITSN1 were not found in ascomycetous S. cerevisiae and Candida albicans, or zygomycetous fungi. Moreover, an Eps15 protein homologous to S. cerevisiae Pan1/Ede1 and additional relevant protein homologs were identified in C. neoformans, suggesting the existence of either a distinct endocytic pathway mediated by Cin1 or pathways by either Cin1 or/and Pan1/Ede1 homologs. Whether and how the Cin1-mediated endocytic pathway represents a unique role in pathogenesis or reflects a redundancy of a transport apparatus remains an open and challenging question. This review discusses recent findings of endocytic adaptor proteins from pathogenic fungi and provides a perspective for novel endocytic machinery operating in C. neoformans. An understanding of intracellular trafficking mechanisms as they relate to pathogenesis will likely reveal the identity of novel antifungal targets.
PubMed | The Research Institute for Children
Type: Journal Article | Journal: Eukaryotic cell | Year: 2011
Human endocytic protein ITSN1 regulates actin reorganization by activating Rho family GTPases, such as Cdc42. The process is enhanced by ITSN binding of WASP, an effector of Cdc42 and a potent activator of actin polymerization. In the human pathogen Cryptococcus neoformans, endocytic protein Cin1 also interacts with Cdc42 and Wsp1, an uncharacterized WASP homolog, but the significance of these interactions remains unknown. Wsp1 contains several conserved domains, including a WASP homology 1 domain (WH1), a GTPase binding/Cdc42 and Rac interactive binding domain (GBD/CRIB), and a C-terminal domain composed of verprolin-like, central, and acidic motifs (VCA). Thus, Wsp1 exhibits domain compositions more similar to human WASP proteins than Saccharomyces cerevisiae Las17/Bee1, a WASP homolog lacking the GDB/CRIB domain. Wsp1 is not an essential protein; however, the wsp1 mutant exhibited defects in growth, cytokinesis, chitin distribution, and endocytosis and exocytosis. The wsp1 mutant was also unable to undergo genetic cross, produce the polysaccharide capsule, or secrete the enzyme urease. An in vitro phagocytosis assay showed a higher phagocytic index for the wsp1 mutant, whose ability to cause lethal infection in a murine model of cryptococcosis was also attenuated. Our studies reveal divergent evolution of WASP proteins in the fungal phylum and suggest that the conserved function of WASP proteins in the actin cytoskeleton may also impact fungal virulence.