Medical Molecular Biology Commons^™

Bacterial Outer Membrane Vesicles Provide An Alternative Pathway For Trafficking Of Escherichia Coli O157 Type Iii Secreted Effectors To Epithelial Cells, Natalie Sirisaengtaksin, Eloise J O'Donoghue, Sara Jabbari, Andrew J Roe, Anne Marie Krachler

Journal Articles

Outer membrane vesicles (OMVs) are proteoliposomes shed by Gram-negative bacteria. Their secretion is enhanced by the transition into the intra-host milieu, and OMVs play critical roles during pathogenesis. Enterohemorrhagic Escherichia coli O157 (EHEC) can cause diarrheal disease in humans, and soluble toxins including Shiga-like toxins that contribute to disease severity and clinical complications like hemolytic uremic syndrome have been shown to be OMV associated. In addition to Shiga-like toxins, EHEC produces a type III secretion system (T3SS), and T3SS effectors are associated with colonization and disease severity in vivo. Here, we show that type III secreted substrates including translocators …

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 …

Illuminating Type Iv Secretion-Mediated Dna Trafficking Through Long Filaments, Peter J Christie

Journal Articles

No abstract provided.

Benzodioxane-Benzamides As Ftsz Inhibitors: Effects Of Linker's Functionalization On Gram-Positive Antimicrobial Activity, Lorenzo Suigo, William Margolin, Eugenia Ulzurrun, Martina Hrast Rambaher, Carlo Zanotto, Victor Sebastián-Pérez, Nuria E Campillo, Valentina Straniero, Ermanno Valoti

Journal Articles

FtsZ is an essential bacterial protein abundantly studied as a novel and promising target for antimicrobials. FtsZ is highly conserved among bacteria and mycobacteria, and it is crucial for the correct outcome of the cell division process, as it is responsible for the division of the parent bacterial cell into two daughter cells. In recent years, the benzodioxane-benzamide class has emerged as very promising and capable of targeting both Gram-positive and Gram-negative FtsZs. In this study, we explored the effect of including a substituent on the ethylenic linker between the two main moieties on the antimicrobial activity and pharmacokinetic properties. …

Cbx4 Promotes Antitumor Immunity By Suppressing Pdcd1 Expression In T Cells., Liwei Ren, Ziyin Li, Yu Zhou, Jun Zhang, Ziheng Zhao, Zhaofei Wu, Ye Zhao, Yurong Ju, Xuewen Pang, Xiuyuan Sun, Wei Wang, Yu Zhang

Journal Articles

E3 SUMO-protein ligase CBX4 (CBX4), a key component of polycomb-repressive complexes 1 (PRC1), has been reported to regulate a variety of genes implicated in tumor growth, metastasis, and angiogenesis. However, its role in T-cell-mediated antitumor immunity remains elusive. To shed light on this issue, we generated mice with T-cell-specific deletion of Cbx4. Tumor growth was increased in the knockout mice. Additionally, their tumor-infiltrating lymphocytes exhibited impaired tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) production, with an elevated programmed cell death protein 1 (PD-1) level. In fact, dysregulated Pdcd1 expression was observed in all major subsets of peripheral T cells from …

Candida Auris-Macrophage Cellular Interactions And Transcriptional Response, Pedro Miramón, Andrew W Pountain, Michael C Lorenz

Journal Articles

The pathogenic yeast Candida auris represents a global threat of the utmost clinical relevance. This emerging fungal species is remarkable in its resistance to commonly used antifungal agents and its persistence in the nosocomial settings. The innate immune system is one the first lines of defense preventing the dissemination of pathogens in the host. C. auris is susceptible to circulating phagocytes, and understanding the molecular details of these interactions may suggest routes to improved therapies. In this work, we examined the interactions of this yeast with macrophages. We found that macrophages avidly phagocytose C. auris; however, intracellular replication is …

The Microtubule Quartet Protein Snap1 In Trypanosoma Brucei Facilitates Flagellum And Cell Division Plane Positioning By Promoting Basal Body Segregation, Thiago Souza Onofre, Kieu T M Pham, Qing Zhou, Ziyin Li

Journal Articles

The unicellular protozoan Trypanosoma brucei has a single flagellum that is involved in cell motility, cell morphogenesis, and cell division. Inheritance of the newly assembled flagellum during the cell cycle requires its correct positioning, which depends on the faithful duplication or segregation of multiple flagellum-associated cytoskeletal structures, including the basal body, the flagellum attachment zone, and the hook complex. Along the flagellum attachment zone sites a set of four microtubules termed the microtubule quartet (MtQ), whose molecular function remains enigmatic. We recently reported that the MtQ-localized protein NHL1 interacts with the microtubule-binding protein TbSpef1 and regulates flagellum inheritance by promoting …

Ligand-Displaying Escherichia Coli Cells And Minicells For Programmable Delivery Of Toxic Payloads Via Type Iv Secretion Systems, Yang Grace Li, Kouhei Kishida, Natsumi Ogawa-Kishida, Peter J Christie

Journal Articles

Bacterial type IV secretion systems (T4SSs) are highly versatile macromolecular translocators and offer great potential for deployment as delivery systems for therapeutic intervention. One major T4SS subfamily, the conjugation machines, are well-adapted for delivery of DNA cargoes of interest to other bacteria or eukaryotic cells but generally exhibit modest transfer frequencies and lack specificity for target cells. Here, we tested the efficacy of a surface-displayed nanobody/antigen (Nb/Ag) pairing system to enhance the conjugative transfer of IncN (pKM101), IncF (F/pOX38), or IncP (RP4) plasmids, or of mobilizable plasmids including those encoding CRISPR/Cas9 systems (pCrispr), to targeted recipient cells. Escherichia coli donors …

Coordination Between Aminoacylation And Editing To Protect Against Proteotoxicity, Hong Zhang, Parker Murphy, Jason Yu, Sukyeong Lee, Francis T F Tsai, Ambro Van Hoof, Jiqiang Ling

Journal Articles

Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that ligate amino acids to tRNAs, and often require editing to ensure accurate protein synthesis. Recessive mutations in aaRSs cause various neurological disorders in humans, yet the underlying mechanism remains poorly understood. Pathogenic aaRS mutations frequently cause protein destabilization and aminoacylation deficiency. In this study, we report that combined aminoacylation and editing defects cause severe proteotoxicity. We show that the ths1-C268A mutation in yeast threonyl-tRNA synthetase (ThrRS) abolishes editing and causes heat sensitivity. Surprisingly, experimental evolution of the mutant results in intragenic mutations that restore heat resistance but not editing. ths1-C268A destabilizes ThrRS and …

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 …

State-Of-The-Art In Carbides/Carbon Composites For Electromagnetic Wave Absorption, Bo Hu, Lixue Gai, Yonglei Liu, Pan Wang, Shuping Yu, Li Zhu, Xijiang Han, Yunchen Du

Journal Articles

Electromagnetic wave absorbing materials (EWAMs) have made great progress in the past decades, and are playing an increasingly important role in radiation prevention and antiradar detection due to their essential attenuation toward incident EM wave. With the flourish of nanotechnology, the design of high-performance EWAMs is not just dependent on the intrinsic characteristics of single-component medium, but pays more attention to the synergistic effects from different components to generate rich loss mechanisms. Among various candidates, carbides and carbon materials are usually labeled with the features of chemical stability, low density, tunable dielectric property, and diversified morphology/microstructure, and thus the combination …

Applications Of Degradable Hydrogels In Novel Approaches To Disease Treatment And New Modes Of Drug Delivery., Bo Hu, Jinyuan Gao, Yu Lu, Yuji Wang

Journal Articles

Hydrogels are particularly suitable materials for loading drug delivery agents; their high water content provides a biocompatible environment for most biomolecules, and their cross-linked nature protects the loaded agents from damage. During delivery, the delivered substance usually needs to be released gradually over time, which can be achieved by degradable cross-linked chains. In recent years, biodegradable hydrogels have become a promising technology in new methods of disease treatment and drug delivery methods due to their many advantageous properties. This review briefly discusses the degradation mechanisms of different types of biodegradable hydrogel systems and introduces the specific applications of degradable hydrogels …

Using Co-Creation Focus Groups To Customise A Remote Multidomain Programme Designed To Increase Dementia Literacy, Walter Wittich, Edeltraut Kröger, Gabrielle Aubin, Asma Fadhlaoui, Nicole D Anderson, Nouha Ben Gaied, Inbal Itzhak, Sylvie Belleville

Journal Articles

Objectives

To adapt the content and functionalities of Brain Health PRO, a web-based multidomain program designed to increase dementia literacy, to the context and needs of users, providers and community organisations across Québec, Canada.

Design

Five consecutive qualitative co-creation focus group sessions 30–90 min in duration each, exploring potential barriers and facilitators to usability, accessibility, comprehensibility, participant recruitment and retention.

Setting

Virtual meetings.

Participants

A 15-member team based in Québec and Ontario, Canada, consisting of 9 researchers (including a graduate student and the project coordinator), representing occupational therapy, sensory rehabilitation, neuropsychology, psychology, health science and research methods, 3 informal caregivers …

Interoceptive Regulation Of Skeletal Tissue Homeostasis And Repair, Yao Xiao, Changhao Han, Yunhao Wang, Xinshu Zhang, Rong Bao, Yuange Li, Huajiang Chen, Bo Hu, Shen Liu

Journal Articles

Recent studies have determined that the nervous system can sense and respond to signals from skeletal tissue, a process known as skeletal interoception, which is crucial for maintaining bone homeostasis. The hypothalamus, located in the central nervous system (CNS), plays a key role in processing interoceptive signals and regulating bone homeostasis through the autonomic nervous system, neuropeptide release, and neuroendocrine mechanisms. These mechanisms control the differentiation of mesenchymal stem cells into osteoblasts (OBs), the activation of osteoclasts (OCs), and the functional activities of bone cells. Sensory nerves extensively innervate skeletal tissues, facilitating the transmission of interoceptive signals to the CNS. …

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 …

New Insights Into Rna Processing By The Eukaryotic Trna Splicing Endonuclease, Cassandra K Hayne, Samoil Sekulovski, Jennifer E Hurtig, Robin E Stanley, Simon Trowitzsch, Ambro Van Hoof

Journal Articles

Through its role in intron cleavage, tRNA splicing endonuclease (TSEN) plays a critical function in the maturation of intron-containing pre-tRNAs. The catalytic mechanism and core requirement for this process is conserved between archaea and eukaryotes, but for decades, it has been known that eukaryotic TSENs have evolved additional modes of RNA recognition, which have remained poorly understood. Recent research identified new roles for eukaryotic TSEN, including processing or degradation of additional RNA substrates, and determined the first structures of pre-tRNA-bound human TSEN complexes. These recent discoveries have changed our understanding of how the eukaryotic TSEN targets and recognizes substrates. Here, …

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 …

China Stroke Surveillance Report 2021, Wen-Jun Tu, Long-De Wang, Special Writing Group Of China Stroke Surveillance Report

Journal Articles

Since 2015, stroke has become the leading cause of death and disability in China, posing a significant threat to the health of its citizens as a major chronic non-communicable disease. According to the China Stroke High-risk Population Screening and Intervention Program, an estimated 17.8 million [95% confidence interval (CI) 17.6–18.0 million] adults in China had experienced a stroke in 2020, with 3.4 million (95% CI 3.3–3.5 million) experiencing their first-ever stroke and another 2.3 million (95% CI 2.2–2.4 million) dying as a result. Additionally, approximately 12.5% (95% CI 12.4–12.5%) of stroke survivors were left disabled, as defined by a modified …

Problems With Peer Review Shine A Light On Gaps In Scientific Training, Diana M Proctor, Nsa Dada, Anna Serquiña, Julia L E Willett

Journal Articles

No abstract provided.

An Unknown Essential Function Of Trna Splicing Endonuclease Is Linked To The Integrated Stress Response And Intron Debranching, Jennifer E Hurtig, Ambro Van Hoof

Journal Articles

tRNA splicing endonuclease (TSEN) has a well-characterized role in transfer RNA (tRNA) splicing but also other functions. For yeast TSEN, these other functions include degradation of a subset of mRNAs that encode mitochondrial proteins and an unknown essential function. In this study, we use yeast genetics to characterize the unknown tRNA-independent function(s) of TSEN. Using a high-copy suppressor screen, we found that sen2 mutants can be suppressed by overexpression of SEN54. This effect was seen both for tRNA-dependent and tRNA-independent functions indicating that SEN54 is a general suppressor of sen2, likely through structural stabilization. A spontaneous suppressor screen identified mutations …

Candida Albicans Hyphal Morphogenesis Within Macrophages Does Not Require Carbon Dioxide Or Ph-Sensing Pathways, Hannah B Wilson, Michael C Lorenz

Journal Articles

The opportunistic fungal pathogen Candida albicans has evolved a variety of mechanisms for surviving inside and escaping macrophages, including the initiation of filamentous growth. Although several distinct models have been proposed to explain this process at the molecular level, the signals driving hyphal morphogenesis in this context have yet to be clarified. Here, we evaluate the following three molecular signals as potential hyphal inducers within macrophage phagosomes: CO2, intracellular pH, and extracellular pH. Additionally, we revisit previous work suggesting that the intracellular pH of C. albicans fluctuates in tandem with morphological changes in vitro. Using time-lapse microscopy, we observed …

Clinical Characteristics And Survival Of Pulmonary Arterial Hypertension With Or Without Interstitial Lung Disease In Systemic Sclerosis, Jessica L Fairley, Dylan Hansen, Laura Ross, Susanna Proudman, Joanne Sahhar, Gene-Siew Ngian, Jennifer Walker, Lauren V Host, Kathleen Morrisroe, Diane Apostolopoulous, Nava Ferdowsi, Michelle Wilson, Maryam Tabesh, Wendy Stevens, Mandana Nikpour

Journal Articles

Objectives

To describe the clinical phenotype and prognosis of people in the Australian Scleroderma (SSc) Cohort Study with pulmonary arterial hypertension (PAH) with or without interstitial lung disease (ILD).

Methods

Participants meeting ACR/EULAR criteria for SSc were divided into four mutually exclusive groups: those meeting criteria for PAH (PAH-only), ILD (ILD-only), concurrent PAH and ILD (PAH-ILD) or neither PAH nor ILD (SSc-only). Logistic or linear regression analyses were used for associations between clinical features, health-related quality of life (HRQoL) and physical function. Survival analysis was performed using Kaplan–Meier estimates and Cox-regression modelling.

Results

Of 1561 participants, 7% fulfilled criteria for …

Nothing About Us Without Us: The Roles Of Diverse Stakeholders In Scientific Publishing, Diana M Proctor

Journal Articles

No abstract provided.

Point-Of-Care Ultrasound In Airway Evaluation And Management: A Comprehensive Review, Judy Lin, Ryan Bellinger, Andrew Shedd, Jon Wolfshohl, Jennifer Walker, Jack Healy, Jimmy Taylor, Kevin Chao, Yi-Hsuan Yen, Ching-Fang Tiffany Tzeng, Eric H Chou

Journal Articles

Airway management is a common and critical procedure in acute settings, such as the Emergency Department (ED) or Intensive Care Unit (ICU) of hospitals. Many of the traditional physical examination methods have limitations in airway assessment. Point-of-care ultrasound (POCUS) has emerged as a promising tool for airway management due to its familiarity, accessibility, safety, and non-invasive nature. It can assist physicians in identifying relevant anatomy of the upper airway with objective measurements of airway parameters, and it can guide airway interventions with dynamic real-time images. To date, ultrasound has been considered highly accurate for assessment of the difficult airway, confirmation …

One Population, Multiple Lifestyles: Commensalism And Pathogenesis In The Human Mycobiome, Diana M Proctor, Rebecca A Drummond, Michail S Lionakis, Julia A Segre

Journal Articles

Candida auris and Candida albicans can result in invasive fungal diseases. And yet, these species can stably and asymptomatically colonize human skin and gastrointestinal tracts. To consider these disparate microbial lifestyles, we first review factors shown to influence the underlying microbiome. Structured by the damage response framework, we then consider the molecular mechanisms deployed by C. albicans to switch between commensal and pathogenic lifestyles. Next, we explore this framework with C. auris to highlight how host physiology, immunity, and/or antibiotic receipt are associated with progression from colonization to infection. While treatment with antibiotics increases the risk an individual will succumb …

The Cgas-Sting Pathway In Diabetic Retinopathy And Age-Related Macular Degeneration, Bo Hu, Jian-Xing Ma, Adam S Duerfeldt

Journal Articles

Diabetic retinopathy and age-related macular degeneration are common retinal diseases with shared pathophysiology, including oxidative stress-induced inflammation. Cellular mechanisms responsible for converting oxidative stress into retinal damage are ill-defined but have begun to clarify. One common outcome of retinal oxidative stress is mitochondrial damage and subsequent release of mitochondrial DNA into the cytosol. This leads to activation of the cGAS-STING pathway, resulting in interferon release and disease-amplifying inflammation. This review summarizes the evolving link between aberrant cGAS-STING signaling and inflammation in common retinal diseases and provides prospective for targeting this system in diabetic retinopathy and age-related macular degeneration. Further defining …

Deep Learning-Enabled Fully Automated Pipeline System For Segmentation And Classification Of Single-Mass Breast Lesions Using Contrast-Enhanced Mammography: A Prospective, Multicentre Study, Tiantian Zheng, Fan Lin, Xianglin Li, Tongpeng Chu, Jing Gao, Shijie Zhang, Ziyin Li, Yajia Gu, Simin Wang, Feng Zhao, Heng Ma, Haizhu Xie, Cong Xu, Haicheng Zhang, Ning Mao

Journal Articles

Background

Breast cancer is the leading cause of cancer-related deaths in women. However, accurate diagnosis of breast cancer using medical images heavily relies on the experience of radiologists. This study aimed to develop an artificial intelligence model that diagnosed single-mass breast lesions on contrast-enhanced mammography (CEM) for assisting the diagnostic workflow.

Methods

A total of 1912 women with single-mass breast lesions on CEM images before biopsy or surgery were included from June 2017 to October 2022 at three centres in China. Samples were divided into training and validation sets, internal testing set, pooled external testing set, and prospective testing set. …

Bacterial Division Ring Stabilizing Zapa Versus Destabilizing Slma Modulate Ftsz Switching Between Biomolecular Condensates And Polymers, Begoña Monterroso, Miguel Ángel Robles-Ramos, Marta Sobrinos-Sanguino, Juan Román Luque-Ortega, Carlos Alfonso, William Margolin, Germán Rivas, Silvia Zorrilla

Journal Articles

Cytokinesis is a fundamental process for bacterial survival and proliferation, involving the formation of a ring by filaments of the GTPase FtsZ, spatio-temporally regulated through the coordinated action of several factors. The mechanisms of this regulation remain largely unsolved, but the inhibition of FtsZ polymerization by the nucleoid occlusion factor SlmA and filament stabilization by the widely conserved cross-linking protein ZapA are known to play key roles. It was recently described that FtsZ, SlmA and its target DNA sequences (SlmA-binding sequence (SBS)) form phase-separated biomolecular condensates, a type of structure associated with cellular compartmentalization and resistance to stress. Using biochemical …

Structural Basis Of A Transcription Pre-Initiation Complex On A Divergent Promoter, Jose J Gorbea Colón, Leon Palao, Shin-Fu Chen, Hee Jong Kim, Laura Snyder, Yi-Wei Chang, Kuang-Lei Tsai, Kenji Murakami

Journal Articles

Most eukaryotic promoter regions are divergently transcribed. As the RNA polymerase II pre-initiation complex (PIC) is intrinsically asymmetric and responsible for transcription in a single direction, it is unknown how divergent transcription arises. Here, the Saccharomyces cerevisiae Mediator complexed with a PIC (Med-PIC) was assembled on a divergent promoter and analyzed by cryoelectron microscopy. The structure reveals two distinct Med-PICs forming a dimer through the Mediator tail module, induced by a homodimeric activator protein localized near the dimerization interface. The tail dimer is associated with ∼80-bp upstream DNA, such that two flanking core promoter regions are positioned and oriented in …

Cell-Membrane-Coated Nanoparticles For Targeted Drug Delivery To The Brain For The Treatment Of Neurological Diseases, Jianzhuang Li, Yanhao Wei, Chunlin Zhang, Rentang Bi, Yanmei Qiu, Yanan Li, Bo Hu

Journal Articles

Neurological diseases (NDs) are a significant cause of disability and death in the global population. However, effective treatments still need to be improved for most NDs. In recent years, cell-membrane-coated nanoparticles (CMCNPs) as drug-targeting delivery systems have become a research hotspot. Such a membrane-derived, nano drug-delivery system not only contributes to avoiding immune clearance but also endows nanoparticles (NPs) with various cellular and functional mimicries. This review article first provides an overview of the function and mechanism of single/hybrid cell-membrane-derived NPs. Then, we highlight the application and safety of CMCNPs in NDs. Finally, we discuss the challenges and opportunities in …