Obesity often occurs with a quintessential array of metabolic abnormalities: elevations in blood pressure, visceral fat, and circulating blood lipids, and, importantly, insulin resistance. Together, this constellation of conditions constitutes the metabolic syndrome and forecasts an individual’s increased risk of developing cardiovascular diseases and type 2 diabetes. Although metabolic syndrome presents as dysfunction across multiple tissues, its onset stems from pathological increases in adipose tissue. The 9 review in this series, conceptualized by series editor Philipp Scherer, delve into the complex biology underlying the metabolic syndrome. These reviews address adipocyte and beta cell dysfunction in the metabolic syndrome; the functions of adipose tissue fibrosis, the microbiome, and exosomal communication in obesity; and the concepts we use to define metabolic health.
The immune system mounts a rapid inflammatory response to injury to mobilize cells and molecular pathways that promote hemostasis and prevent infection, but this acute response is only the first phase of recovery. Wound repair and inflammation-resolving processes are essential to recovering homeostasis in the aftermath of an injury: inefficient healing or prolonged inflammation can drive chronic dysfunction in the affected tissue. The Reparative Immunology series highlights the immune system’s contributions to these critical repair processes, from the roles of T cells, macrophages, neutrophils, and innate lymphoid cells in physiological repair to the influence of cytokine signaling, immunometabolism, and epigenetic reprogramming on pathological outcomes of injury. Together, these reviews emphasize the complexity of the immune environment in injured tissue and indicate numerous potential opportunities to intervene in dysfunctional wound-healing.
Published July 2019
The increasing prevalence of allergies worldwide has spurred numerous efforts to better understand risk factors and mechanisms underlying these potentially life-threatening immune responses. Coordinated by Series Editor Kari Nadeau, these reviews address our evolving understanding of the shared and distinct mechanisms underlying allergic diseases of the skin, respiratory system, and gastrointestinal tract. In topics ranging from the molecular and cellular basis of allergy to the influence of the central nervous system, microbiome, and environment, leaders in the field highlight major insights into allergic responses as well as new concepts in treating and preventing allergy.
Published April 2019
Heritable germline mutations are estimated to drive 10% of all cancers, which can manifest as pediatric as well as adult diseases. This series, curated by Agata Smogorzewska and JCI Associate Editor Mary Armanios, unravels how the biology and genetics underlying familial cancer predisposition syndromes informs understanding of cancer etiology and biology. Reviews focus on cancer-driving mutations in transcription factors, in developmental and metabolic signals, and in pathways that control genetic stability and provide insights linking mechanistic studies with ongoing clinical research. Enhanced understanding of the biological basis for these familial cancers may inform the treatment of cancers driven by both germline and somatic mutations.
Published February 2019
Mitochondria transform nutrients and oxygen into chemical energy that powers a multitude of cellular functions. While mitochondrial aerobic glycolysis generates the majority of a cell’s ATP, its byproducts also have wide-ranging influences on cellular health and longevity. This review series, edited by Dr. Michael Sack, focuses on the many contributions of mitochondria to disease and aging. The reviews highlight evidence linking altered mitochondrial metabolism and oxidative stress to a range of pathophysiological phenomena: inflammation and immune dysfunction, heart failure, cancer development, metabolic disease, and more. In many diseases and conditions, mitochondrial dysfunction is considered the tipping point toward pathological progression. However, as these reviews discuss, therapeutic targeting of mitochondria may be a powerful strategy to subvert disease and aging processes.
Published August 2018
Infection and injury induce self-limited inflammatory responses that mount a defense against pathogens and initiate activities that expedite recovery. However, the benefits of inflammation recede when these responses fail to resolve in a timely manner. This series features a family of specialized lipid mediators that regulate the resolution of inflammation. The reviews, curated by Charles Serhan, highlight the wide-ranging involvement of these bioactive lipids in health and disease. Work by Serhan and others has revealed that the resolvin, protectin, and maresin families of pro-resolving mediators act as immunoresolvents and represent promising alternatives to immunosuppressant and anti-inflammatory therapies. Other lipid mediators, including leukotrienes, ceramides, and sphingolipids have roles in cancer, cardiovascular disease, and aging. Our evolving understanding of lipid mediators in regulating inflammation and disease pathogenesis presents promising opportunities for new therapeutic strategies.
Published July 2018
Cellular senescence is a normal consequence of aging, resulting from lifelong accumulation of DNA damage that triggers an end to cell replication. Although senescent cells no longer divide, they persist in their tissue of origin and develop characteristics that can hasten and exacerbate age-related disease. This series addresses the contribution of cellular senescence to cardiovascular, neurodegenerative, and arthritic disorders as well as the senescent phenotypes in various tissues and cell types. In addition to their cell-intrinsic effects, senescent cells develop the ability to negatively influence healthy neighboring cells and immune cells by secreting senescence-associated set of cytokines and mediators known as the SASP. These reviews also highlight ongoing efforts to accurately identify, target, and eliminate senescent cells or otherwise combat their deleterious effects in disease. One day, this work may provide the basis for therapies targeting aging cells in multiple organs.
Published April 2018
Fibrosis describes a maladaptive response to injury that results in pathogenic production of extracellular matrix, the formation of stiff scar tissue, and compromised organ function. Although it is most often associated with chronic liver conditions and progressive lung disease, fibrosis can affect any organ of the body. There are few treatment options for this progressive, often fatal condition, but as ongoing research identifies the molecular pathways that initiate and propagate fibrotic remodeling, therapeutic possibilities may become available. The reviews in this series discuss recent insights into genetic predisposition to fibrotic disorders, the origins of fibroblasts and myofibroblasts, scar tissue formation, organ regeneration, and more, revealing opportunities to interrupt or even reverse disease progression.
Published January 2018
Glia are central nervous system cells that surround neurons and hold them in place, supply them with nutrients and oxygen, serve to insulate neurons from each other, and to remove pathogens and dead neurons. Historically, these cells have been considered less interesting than neurons; however, in the past decade, they have emerged as critical regulators of brain development and homeostasis and are now being appreciated as drivers of disease. Reviews in this series describe the role of glia and the associated glymphatic system in normal physiology, neuronal metabolism, prion diseases, Alzheimer’s disease, ALS, spinal cord injury, and neurodegenerative disease.
Published September 2017
Organ and tissue transplantation are frequently life-extending procedures for patients with end-stage organ disease or hematological malignancies; however, the success of transplantation of organs and tissues to a recipient from a genetically non-identical donor is limited by immune-mediated complications, including rejection, graft dysfunction, graft-versus-host disease, and the side effects of preventing rejection. Despite over 100 years of research in this area, we are just now beginning to develop an in-depth understanding of the immune mechanisms that determine the success of allotransplantation. A detailed understanding of transplantation immunology will allow for better selection of donor/recipient pairs, the development of novel therapeutic strategies, and, ultimately, better outcomes. Reviews in this series explore the role of cytokines in both acute and chronic graft-versus-host disease; the effects of sterile inflammation, danger signals, and the inflammasome in solid organ transplantation; the mechanisms of humoral and cellular rejection; cell-based therapies to combat rejection and transplantation-associated infections; and the effects of both host-intrinsic and -extrinsic factors in transplantation outcomes.
Published June 2017