Annual review of physiology最新文献

Store-operated Ca2+ entry (SOCE) is a widespread mechanism of cellular Ca2+ signaling that arises from Ca2+ influx across the plasma membrane through the Orai family of calcium channels in response to depletion of intracellular Ca2+ stores. Orai channels are a crucial Ca2+ entry mechanism in both neurons and glia and are activated by a unique inside-out gating process involving interactions with the endoplasmic reticulum Ca2+ sensors, STIM1 and STIM2. Recent evidence indicates that SOCE is broadly found across all areas of the nervous system where its physiology and pathophysiology is only now beginning to be understood. Here, we review the growing literature on the mechanisms of SOCE in the nervous system and contributions to gene expression, neuronal excitability, synaptic plasticity, and behavior. We also explore the burgeoning links between SOCE and neurological disease and discuss therapeutic implications of targeting SOCE for brain disorders.

Two major functions of the lymphatic system are the reabsorption of excess interstitial fluid/protein and the coordination of immune cell interactions and trafficking. Specialized junctions between lymphatic endothelial cells optimize reabsorption. The spontaneous contractions of collecting vessels provide active lymph propulsion. One-way valves prevent backflow, and chemokine gradients direct the migration of immune cells. Specialized compartments within the lymph node facilitate antigen-immune cell interactions to produce innate and acquired immunity. Lymphatic injury and/or mutations in genes controlling vessel/valve development result in contractile/valve dysfunction, reduced immune cell trafficking and, ultimately, lymph-edema. Activated CD4+ T cells produce inflammatory mediators that exacerbate these processes, potentially leading to interstitial and lymphatic vessel remodeling and negatively impacting overall function. Mouse models have advanced our knowledge of lymphatic disease, but clinical trials to reduce the impact of inflammatory mediators have yielded mixed success, implying that additional factors underlying human lymphedema are not yet understood.

The liver plays a central role in regulating lipid and glucose metabolism, particularly in transitioning between energy storage and provision in fed and fasting states. Loss of metabolic flexibility, characterized by the impaired capacity to shift between different energy substrates, sets the stage for accumulation of hepatic triglyceride as lipid droplets and further metabolic perturbations. Cross talk between the liver and other organs, including adipose tissue, pancreas, and muscle, is relevant in this transition. In addition to the metabolic consequences of steatosis, there are significant liver risks related to triggered inflammatory and fibrotic processes. Steatotic liver diseases affect an estimated one in three adults globally and contribute to substantial morbidity and mortality. This review focuses on the liver's role in lipid metabolism, defining metabolic health and unhealth, the pathogenic underpinnings that lead to steatohepatitis and hepatic fibrosis, and the clinical features and therapies for the most common forms of steatotic liver diseases.

Preterm fetuses and newborns have a high risk of neural injury and impaired neural maturation, leading to neurodevelopmental disability. Developing effective treatments is rather challenging, as preterm brain injury may occur at any time during pregnancy and postnatally, and many cases involve multiple pathogenic factors. This review examines research on how the preterm fetus responds to hypoxia-ischemia and how brain injury evolves after hypoxia-ischemia, offering windows of opportunity for treatment and insights into the mechanisms of injury during key phases. We highlight research showing that preterm fetuses can survive hypoxia-ischemia and continue development in utero with evolving brain injury. Early detection of fetal brain injury would provide an opportunity for treatments to reduce adverse neurodevelopmental outcomes, including cerebral palsy. However, this requires that we can detect injury using noninvasive methods. We discuss how circadian changes in fetal heart rate variability may offer utility as a biomarker for detecting injury and phases of injury.

The SLC12 family of genes encodes electroneutral Cl--dependent cation transporters (i.e., Na-Cl, K-Cl, Na-K-2Cl cotransporters), which play significant roles in maintaining cell and body homeostasis. Recent resolution of their structures at the atomic level provides a new understanding how these transporters operate in health and disease and how they are targeted for therapeutic intervention. Overall, the SLC12 transporter cryo-EM structures confirm some key features established by traditional biochemical and molecular methods, such as the presence of 12 transmembrane domains and the formation of a functional dimer. Study of these structures also uncovers previously unknown features, such as the presence of strategic salt bridges that explain why transporters are stabilized in specific conformations. The cryo-EM structures show similarities with other transport protein structures, especially regarding the position of the cations. The structures also pose challenging questions regarding the number of ions bound and the strict electroneutrality that is conventional understanding.

Over the last decade, single-cell genomics has revealed remarkable heterogeneity and plasticity of cell types in the lungs and airways. The challenge now is to understand how these cell types interact in three-dimensional space to perform lung functions, facilitating airflow and gas exchange while simultaneously providing barrier function to avoid infection. An explosion in novel spatially resolved gene expression technologies, coupled with computational tools that harness machine learning and deep learning, now promise to address this challenge. Here, we review the most commonly used spatial analysis workflows, highlighting their advantages and limitations, and outline recent developments in machine learning and artificial intelligence that will augment how we interpret spatial data. Together these technologies have the potential to transform our understanding of the respiratory system in health and disease, and we showcase studies in lung development, COVID-19, lung cancer, and fibrosis where spatially resolved transcriptomics is already providing novel insights.

Lung inflammation, infection, and injury can lead to critical illness and death. The current means to pharmacologically treat excessive uncontrolled lung inflammation needs improvement because many treatments are or will become immunosuppressive. The inflammatory response evolved to protect the host from microbes, injury, and environmental insults. This response brings phagocytes from the bloodstream to the tissue site to phagocytize and neutralize bacterial invaders and enables airway antimicrobial functions. This physiologic response is ideally self-limited with initiation and resolution phases. Polyunsaturated essential fatty acids are precursors to potent molecules that govern both phases. In the initiation phase, arachidonic acid is converted to prostaglandins and leukotrienes that activate leukocytes to transmigrate from postcapillary venules. The omega-3 fatty acids (e.g., DHA and EPA) are precursors to resolvins, protectins, and maresins, which are families of chemically distinct mediators with potent functions in resolution of acute and chronic inflammation in the respiratory system.

Endothelial cells (ECs) develop organ-specific gene expression and function in response to signals from the surrounding tissue. In turn, ECs can affect organ development and morphogenesis and promote or hinder disease response. In the lung, ECs play an essential role in gas exchange with the external environment, requiring both a close physical connection and a strong axis of communication with alveolar epithelial cells. A complete picture of the composition of the pulmonary endothelium is therefore critical for a full understanding of development, maintenance, and repair of the gas exchange interface. Defining the factors that control lung-specific EC specification, establish EC heterogeneity within the lung, and promote the differing contributions of EC subtypes to development, health, and disease will facilitate the development of much-needed regenerative therapies. This includes targeting therapeutics directly to ECs, developing pluripotent or primary cell-derived ECs to replace damaged or diseased vasculature, and vascularizing engineered tissues for transplant.

Inositol 1,4,5-trisphosphate receptors (IP₃Rs) are ubiquitous intracellular Ca2+ release channels. Their activation, subcellular localization, abundance, and regulation play major roles in defining the spatiotemporal characteristics of intracellular Ca2+ signals, which are in turn fundamental to the appropriate activation of effectors that control a myriad of cellular events. Over the past decade, ∼100 mutations in ITPRs associated with human diseases have been documented. Mutations have been detailed in all three IP₃R subtypes and all functional domains of the protein, resulting in both gain and loss of receptor function. IP₃R mutations are associated with a diverse array of pathology including spinocerebellar ataxia, peripheral neuropathy, immunopathy, anhidrosis, hyperparathyroidism, and squamous cell carcinoma. This review focuses on how studying the altered activity of these mutations provides information relating to IP₃R structure and function, the physiology underpinned by specific IP₃R subtypes, and the pathological consequences of dysregulated Ca2+ signaling in human disease.

The increased prevalence of chronic metabolic disorders, including obesity and type 2 diabetes and their associated comorbidities, are among the world's greatest health and economic challenges. Metabolic homeostasis involves a complex interplay between hormones that act on different tissues to elicit changes in the storage and utilization of energy. Such processes are mediated by tyrosine phosphorylation-dependent signaling, which is coordinated by the opposing actions of protein tyrosine kinases and protein tyrosine phosphatases (PTPs). Perturbations in the functions of PTPs can be instrumental in the pathophysiology of metabolic diseases. The goal of this review is to highlight key advances in our understanding of how PTPs control body weight and glucose metabolism, as well as their contributions to obesity and type 2 diabetes. The emerging appreciation of the integrated functions of PTPs in metabolism, coupled with significant advances in pharmaceutical strategies aimed at targeting this class of enzymes, marks the advent of a new frontier in combating metabolic disorders.