Medical Microbiology Commons^™

Optimization Of The Antifungal Properties Of The Bacterial Peptide Entv By Variant Analysis, Shantanu Guha, Shane A Cristy, Giuseppe Buda De Cesare, Melissa R Cruz, Michael C Lorenz, Danielle A Garsin

Journal Articles

Fungal resistance to commonly used medicines is a growing public health threat, and there is a dire need to develop new classes of antifungals. We previously described a peptide produced by Enterococcus faecalis, EntV, that restricts Candida albicans to a benign form rather than having direct fungicidal activity. Moreover, we showed that one 12-amino acid (aa) alpha helix of this peptide retained full activity, with partial activity down to the 10aa alpha helix. Using these peptides as a starting point, the current investigation sought to identify the critical features necessary for antifungal activity and to screen for new variants …

A Mutation In F-Actin Polymerization Factor Suppresses The Distal Arthrogryposis Type 5 Piezo2 Pathogenic Variant In Caenorhabditis Elegans, Xiaofei Bai, Harold E Smith, Luis O Romero, Briar Bell, Valeria Vásquez, Andy Golden

Journal Articles

The mechanosensitive PIEZO channel family has been linked to over 26 disorders and diseases. Although progress has been made in understanding these channels at the structural and functional levels, the underlying mechanisms of PIEZO-associated diseases remain elusive. In this study, we engineered four PIEZO-based disease models using CRISPR/Cas9 gene editing. We performed an unbiased chemical mutagen-based genetic suppressor screen to identify putative suppressors of a conserved gain-of-function variant pezo-1[R2405P] that in human PIEZO2 causes distal arthrogryposis type 5 (DA5; p. R2718P). Electrophysiological analyses indicate that pezo-1(R2405P) is a gain-of-function allele. Using genomic mapping and whole-genome sequencing approaches, we identified a …

Colonization Of Larval Zebrafish (Danio Rerio) With Adherent-Invasive Escherichia Coli Prevents Recovery Of The Intestinal Mucosa From Drug-Induced Enterocolitis, Erika Flores, Soumita Dutta, Rachel Bosserman, Ambro Van Hoof, Anne-Marie Krachler

Journal Articles

Although inflammatory bowel diseases are on the rise, what factors influence IBD risk and severity, and the underlying mechanisms remain to be fully understood. Although host genetics, microbiome, and environmental factors have all been shown to correlate with the development of IBD, cause and effect are difficult to disentangle in this context. For example, AIEC is a known pathobiont found in IBD patients, but it remains unclear if gut inflammation during IBD facilitates colonization with AIEC, or if AIEC colonization makes the host more susceptible to pro-inflammatory stimuli. It is critical to understand the mechanisms that contribute to AIEC infections …

Catalase Produced By Candida Albicans Protects Streptococcus Mutans From H2o2 Stress-One More Piece In The Cross-Kingdom Synergism Puzzle, Callahan Katrak, Bruna A Garcia, Louise M Dornelas-Figueira, Mary Nguyen, Robert B Williams, Michael C Lorenz, Jacqueline Abranches

Journal Articles

Co-infection with Streptococcus mutans and Candida albicans is associated with dental caries, and their co-cultivation results in enhanced biofilm matrix production that contributes to increased virulence and caries risk. Moreover, the catalase-negative S. mutans demonstrates increased oxidative stress tolerance when co-cultivated in biofilms with C. albicans, a catalase-producing yeast. Here, we sought to obtain mechanistic insights into the increased H2O2 tolerance of S. mutans when co-cultivated with clinical isolates of Candida glabrata, Candida tropicalis, and C. albicans. Additionally, the C. albicans SC5314 laboratory strain, its catalase mutant (SC5314Δcat1), and S. mutans UA159 and its glucosyltransferase B/C …

The Circadian Nobiletin-Ror Axis Suppresses Adipogenic Differentiation And Iκbα/Nf-Κb Signaling In Adipocytes, Eunju Kim, Kazuaki Mawatari, Seung-Hee Yoo, Zheng Chen

Journal Articles

Obesity is a known risk factor for metabolic diseases and is often associated with chronic inflammation in adipose tissue. We previously identified the polyethoxylated flavonoid Nobiletin (NOB) as a circadian clock modulator that directly binds to and activates the ROR receptors in the core oscillator, markedly improving metabolic fitness in obese mice. Here, we show that NOB enhanced the oscillation of core clock genes in differentiated 3T3-L1 adipocytes, including ROR target genes such as Bmal1, Cry1, Dec1, and Dec2. NOB inhibited lipid accumulation in 3T3-L1 and SVF cells, concomitant with the dysregulated circadian expression of adipogenic …

Host-Derived Reactive Oxygen Species Trigger Activation Of The Candida Albicans Transcription Regulator Rtg1/3, Mazen Oneissi, Melissa R Cruz, Bernardo Ramírez-Zavala, Elena Lindemann-Perez, Joachim Morschhäuser, Danielle A Garsin, J Christian Perez

Journal Articles

The signals that denote mammalian host environments and dictate the activation of signaling pathways in human-associated microorganisms are often unknown. The transcription regulator Rtg1/3 in the human fungal pathogen Candida albicans is a crucial determinant of host colonization and pathogenicity. Rtg1/3's activity is controlled, in part, by shuttling the regulator between the cytoplasm and nucleus of the fungus. The host signal(s) that Rtg1/3 respond(s) to, however, have remained unclear. Here we report that neutrophil-derived reactive oxygen species (ROS) direct the subcellular localization of this C. albicans transcription regulator. Upon engulfment of Candida cells by human or mouse neutrophils, the regulator …

Probiotic-Derived Ecto-5'-Nucleotidase Produces Anti-Inflammatory Adenosine Metabolites In Treg-Deficient Scurfy Mice, Yuying Liu, Shabba A Armbrister, Beanna Okeugo, Tingting W Mills, Rhea C Daniel, Jee-Hwan Oh, Jan-Peter Van Pijkeren, Evelyn S Park, Zeina M Saleh, Sharmistha Lahiri, Stefan Roos, Jmarc Rhoads

Journal Articles

Probiotic Limosilactobacillus reuteri DSM 17938 (DSM 17938) prolongs the survival of Treg-deficient scurfy (SF) mice and reduces multiorgan inflammation by a process requiring adenosine receptor 2A (A2A) on T cells. We hypothesized that L. reuteri-derived ecto-5’-nucleotidase (ecto-5’NT) activity acts to generate adenosine, which may be a central mediator for L. reuteri protection in SF mice. We evaluated DSM 17938–5’NT activity and the associated adenosine and inosine levels in plasma, gut, and liver of SF mice. We examined orally fed DSM 17938, DSM 17938Δ5NT (with a deleted 5’NT gene), and DSM 32846 (BG-R46) (a naturally selected strain derived from DSM …

Interleukin-33 Facilitates Liver Regeneration Through Serotonin-Involved Gut-Liver Axis, Yankai Wen, Christoph Emontzpohl, Long Xu, Constance L Atkins, Jong-Min Jeong, Yang Yang, Kangho Kim, Chuan Wu, Shizuo Akira, Cynthia Ju

Journal Articles

BACKGROUND AND AIMS: Insufficient liver regeneration causes post-hepatectomy liver failure and small-for-size syndrome. Identifying therapeutic targets to enhance hepatic regenerative capacity remains urgent. Recently, increased IL-33 was observed in patients undergoing liver resection and in mice after partial hepatectomy (PHx). The present study aims to investigate the role of IL-33 in liver regeneration after PHx and to elucidate its underlying mechanisms.

APPROACH AND RESULTS: We performed PHx in IL-33 -/- , suppression of tumorigenicity 2 (ST2) -/- , and wild-type control mice, and found deficiency of IL-33 or its receptor ST2 delayed liver regeneration. The insufficient liver regeneration could be …

Stat6 Suppression Prevents Bleomycin-Induced Dermal Fibrosis, Jingjing Huang, Hydia Puente, Nancy E Wareing, Minghua Wu, Maureen D Mayes, Harry Karmouty-Quintana, Shervin Assassi, Tingting W Mills

Journal Articles

Fibrosis of the skin and internal organs is a hallmark of systemic sclerosis (SSc). Although the pathogenesis of SSc is poorly understood, increasing evidence suggests that interleukins (IL)-4 and - 13 contribute to the pathogenesis of skin fibrosis by promoting collagen production and myofibroblast differentiation. Signal transducers and activators of transcription 6 (STAT6) is one of the most important downstream transcription factors activated by both IL-4 and IL-13. However, it is not completely understood whether STAT6 plays a role during the pathogenesis of skin fibrosis in SSc. In this study, we observed increased STAT6 phosphorylation in fibrotic skin samples collected …

Excessive Mechanotransduction In Sensory Neurons Causes Joint Contractures, Shang Ma, Adrienne E Dubin, Luis O Romero, Meaghan Loud, Alexandra Salazar, Sarah Chu, Nikola Klier, Sameer Masri, Yunxiao Zhang, Yu Wang, Alex T Chesler, Katherine A Wilkinson, Valeria Vásquez, Kara L Marshall, Ardem Patapoutian

Journal Articles

Distal arthrogryposis (DA) is a collection of rare disorders that are characterized by congenital joint contractures. Most DA mutations are in muscle- and joint-related genes, and the anatomical defects originate cell-autonomously within the musculoskeletal system. However, gain-of-function mutations in PIEZO2, a principal mechanosensor in somatosensation, cause DA subtype 5 (DA5) through unknown mechanisms. We show that expression of a gain-of-function PIEZO2 mutation in proprioceptive sensory neurons that mainly innervate muscle spindles and tendons is sufficient to induce DA5-like phenotypes in mice. Overactive PIEZO2 causes anatomical defects through increased activity within the peripheral nervous system during postnatal development. Furthermore, botulinum toxin …

Hepatic Circadian And Differentiation Factors Control Liver Susceptibility For Fatty Liver Disease And Tumorigenesis, Baharan Fekry, Aleix Ribas-Latre, Rachel Van Drunen, Rafael Bravo Santos, Samay Shivshankar, Yulin Dai, Zhongming Zhao, Seung-Hee Yoo, Zheng Chen, Kai Sun, Frances M Sladek, Mamoun Younes, Kristin Eckel-Mahan

Journal Articles

Hepatocellular carcinoma (HCC) is a leading cause of cancer deaths, and the most common primary liver malignancy to present in the clinic. With the exception of liver transplant, treatment options for advanced HCC are limited, but improved tumor stratification could open the door to new treatment options. Previously, we demonstrated that the circadian regulator Aryl Hydrocarbon-Like Receptor Like 1 (ARNTL, or Bmal1) and the liver-enriched nuclear factor 4 alpha (HNF4α) are robustly co-expressed in healthy liver but incompatible in the context of HCC. Faulty circadian expression of HNF4α- either by isoform switching, or loss of expression- results in an increased …

Kalium Channelrhodopsins Are Natural Light-Gated Potassium Channels That Mediate Optogenetic Inhibition, Elena G Govorunova, Yueyang Gou, Oleg A Sineshchekov, Hai Li, Xiaoyu Lu, Yumei Wang, Leonid S Brown, François St-Pierre, Mingshan Xue, John L Spudich

Journal Articles

Channelrhodopsins are used widely for optical control of neurons, in which they generate photoinduced proton, sodium or chloride influx. Potassium (K+) is central to neuron electrophysiology, yet no natural K+-selective light-gated channel has been identified. Here, we report kalium channelrhodopsins (KCRs) from Hyphochytrium catenoides. Previously known gated potassium channels are mainly ligand- or voltage-gated and share a conserved K+-selectivity filter. KCRs differ in that they are light-gated and have independently evolved an alternative K+ selectivity mechanism. The KCRs are potent, highly selective of K+ over Na+, and open in less than 1 ms following photoactivation. The permeability ratio PK/PNa of …

The Brief Case:, Eileen M Burd, Ahmed Babiker, Jessica K Fairley, Divya Bhamidipati, Laila E Woc-Colburn, Blaine A Mathison

Journal Articles

No abstract provided.