Molecular biology of autoinflammatory diseases

Protein profile at newly restored implants compared to contralateral teeth over 12-months: a pilot study

OBJECTIVES

To determine crevicular fluid alterations in protein expression of newly restored implants during their first year of function and associate them with those of contralateral teeth.

MATERIALS AND METHODS

In ten non-smokers, successfully treated for periodontitis, one newly restored implant (baseline-T0) and one corresponding tooth were followed for 12-months (T1). Oral hygiene was monitored during the study. Periodontal clinical indices and crevicular fluid were collected from an implant-site (PICF) and a tooth-site (GCF). Total proteomic profiles of PICF and GCF were investigated using label-free quantitative proteomics.

RESULTS

Clinical recordings remained stable at 12-months on the tooth-/implant-site basis. The comparative analysis of protein enrichment between teeth and implants at T0 revealed 664 human proteins, with 93 found only in teeth and 217 exclusively in implants. Among the 354 overlapping proteins, 46 were upregulated (log2FC > 1) in teeth, while 61 in implants. At T1, 569 human proteins were exclusively identified, with 67 found only in teeth and 193 exclusively in implants. Of the 309 overlapping proteins, 22 were upregulated in teeth, while 48 were in implants. The over-representation enrichment analysis identified "interferon-alpha response" and "allograft rejection" pathways, as significantly regulated categories at T0, with the latter being over-represented at T1.

CONCLUSIONS

Peri-implant tissue maturation was evident during the study. Proteins expressed in crevicular fluid reflected unique patterns between implants and teeth that are worth studying.

CLINICAL RELEVANCE

Different proteomic patterns were observed at the implant-site compared to the contralateral tooth-site towards inflammatory processes that prevail within otherwise clinically healthy peri-implant tissues.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov ID: NCT06379022.

Mitochondrial Targeted Interventions for Aging

Changes in mitochondrial function play a critical role in the basic biology of aging and age-related disease. Mitochondria are typically thought of in the context of ATP production and oxidant production. However, it is clear that the mitochondria sit at a nexus of cell signaling where they affect metabolite, redox, and energy status, which influence many factors that contribute to the biology of aging, including stress responses, proteostasis, epigenetics, and inflammation. This has led to growing interest in identifying mitochondrial targeted interventions to delay or reverse age-related decline in function and promote healthy aging. In this review, we discuss the diverse roles of mitochondria in the cell. We then highlight some of the most promising strategies and compounds to target aging mitochondria in preclinical testing. Finally, we review the strategies and compounds that have advanced to clinical trials to test their ability to improve health in older adults.

Cellular models in autoinflammatory disease research

Systemic autoinflammatory diseases are a heterogeneous group of rare genetic disorders caused by dysregulation of the innate immune system. Understanding the complex mechanisms underlying these conditions is critical for developing effective treatments. Cellular models are essential for identifying new conditions and studying their pathogenesis. Traditionally, these studies have used primary cells and cell lines of disease-relevant cell types, although newer induced pluripotent stem cell (iPSC)-based models might have unique advantages. In this review, we discuss the three cellular models used in autoinflammatory disease research, their strengths and weaknesses, and their applications to inform future research in the field.

Systemic autoinflammatory disorders

Inflammation is a physiologic defense mechanism against an out-side attack. Usually, it resolves after the removal of noxious causes, but systemic autoinflammatory disorders (SAIDs) have recurrent or repeated acute inflammation through uncontrolled gene function, which can present as gain-of-function or loss-of-function of a gene during inflammation. Most SAIDs are hereditary autoinflammatory diseases and develop by dysregulation of innate immunity through various pathways including inflammasomes, endoplasmic reticulum stress, nuclear factor-κB dysregulation, and interferon production. The clinical manifestations include periodic fever with various skin findings such as neutrophilic urticarial dermatosis, or vasculitic lesions. Some SAID cases stem from immunodeficiency or allergic reactions related to monogenic mutation. The diagnosis of SAIDs is based on clinical findings of systemic inflammation and genetic confirmation, and have to exclude infections or malignancies. Moreover, a genetic study is essential for clinical features to be suspect SAID with or without a family history. Treatment is based on understanding the immunopathology of SAID, and targeted therapy to control disease flares, reduce recurrent acute phases and prevent serious complications. Diagnosing and treating SAID requires understanding its comprehensive clinical features and pathogenesis related to genetic mutation.

Tackling TNF-α in autoinflammatory disorders and autoimmune diseases: From conventional to cutting edge in biologics and RNA- based nanomedicines

Autoinflammatory disorders and autoimmune diseases result from abnormal deviations of innate and adaptive immunity that heterogeneously affect organs and clinical phenotypes. Despite having etiologic and phenotypic differences, these two conditions share the onset of an aberrant inflammatory process. Targeting the main drivers controlling inflammation is useful to treat both autoimmune and autoinflammatory syndromes. TNF-α is a major player in the inflammatory immune response, and anti-TNF-α antibodies have been a revolutionary treatment in many autoimmune disorders. However, production difficulties and high development costs hinder their implementation, and accessibility to their use is still limited. Innovative strategies aimed at overcoming the limitations associated with anti-TNF-α antibodies are being explored, including RNA-based therapies. Here we summarize the central role of TNF-α in immune disorders and how anti-TNF-based immunotherapies changed the therapeutic landscape, albeit with important limitations related to side effects, tolerance, and resistance to therapies. We then outline how nanotechnology has provided the final momentum for the use of nucleic acids in the treatment of autoimmune and autoinflammatory diseases, with a focus on inflammatory bowel diseases (IBDs). The example of IBDs allows the evaluation and discussion of the nucleic acids-based treatments that have been developed, to identify the role that innovative approaches possess in view of the treatment of autoinflammatory disorders and autoimmune diseases.

A novel murine model of pyoderma gangrenosum reveals that inflammatory skin-gut crosstalk is mediated by IL-1β-primed neutrophils

Pyoderma gangrenosum (PG) is a debilitating skin condition often accompanied by inflammatory bowel disease (IBD). Strikingly, ~40% of patients that present with PG have underlying IBD, suggesting shared but unknown mechanisms of pathogenesis. Impeding the development of effective treatments for PG is the absence of an animal model that exhibits features of both skin and gut manifestations. This study describes the development of the first experimental drug-induced mouse model of PG with concomitant intestinal inflammation. Topical application of pyrimidine synthesis inhibitors on wounded mouse skin generates skin ulcers enriched in neutrophil extracellular traps (NETs) as well as pro-inflammatory cellular and soluble mediators mimicking human PG. The mice also develop spontaneous intestinal inflammation demonstrated by histologic damage. Further investigations revealed increased circulating low density IL-1β primed neutrophils that undergo enhanced NETosis at inflamed tissue sites supported by an increase in circulatory citrullinated histone 3, a marker of aberrant NET formation. Granulocyte depletion dampens the intestinal inflammation in this model, further supporting the notion that granulocytes contribute to the skin-gut crosstalk in PG mice. We anticipate that this novel murine PG model will enable researchers to probe common disease mechanisms and identify more effective targets for treatment for PG patients with IBD.

Interactions between the NLRP3-Dependent IL-1β and the Type I Interferon Pathways in Human Plasmacytoid Dendritic Cells

Generally, a reciprocal antagonistic interaction exists between the antiviral type I interferon (IFN) and the antibacterial nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain containing 3 (NLRP3)-dependent IL-1β pathways that can significantly shape immune responses. Plasmacytoid dendritic cells (pDCs), as professional type I IFN-producing cells, are the major coordinators of antiviral immunity; however, their NLRP3-dependent IL-1β secretory pathway is poorly studied. Our aim was to determine the functional activity of the IL-1β pathway and its possible interaction with the type I IFN pathway in pDCs. We found that potent nuclear factor-kappa B (NF-κB) inducers promote higher levels of pro-IL-1β during priming compared to those activation signals, which mainly trigger interferon regulatory factor (IRF)-mediated type I IFN production. The generation of cleaved IL-1β requires certain secondary signals in pDCs and IFN-α or type I IFN-inducing viruses inhibit IL-1β production of pDCs, presumably by promoting the expression of various NLRP3 pathway inhibitors. In line with that, we detected significantly lower IL-1β production in pDCs of psoriasis patients with elevated IFN-α levels. Collectively, our results show that the NLRP3-dependent IL-1β secretory pathway is inducible in pDCs; however, it may only prevail under inflammatory conditions, in which the type I IFN pathway is not dominant.

Prenylation Defects and Oxidative Stress Trigger the Main Consequences of Neuroinflammation Linked to Mevalonate Pathway Deregulation

The cholesterol biosynthesis represents a crucial metabolic pathway for cellular homeostasis. The end products of this pathway are sterols, such as cholesterol, which are essential components of cell membranes, precursors of steroid hormones, bile acids, and other molecules such as ubiquinone. Furthermore, some intermediates of this metabolic system perform biological activity in specific cellular compartments, such as isoprenoid molecules that can modulate different signal proteins through the prenylation process. The defects of prenylation represent one of the main causes that promote the activation of inflammation. In particular, this mechanism, in association with oxidative stress, induces a dysfunction of the mitochondrial activity. The purpose of this review is to describe the pleiotropic role of prenylation in neuroinflammation and to highlight the consequence of the defects of prenylation.

Inflammation: A New Look at an Old Problem

Pro-inflammatory stress is inherent in any cells that are subject to damage or threat of damage. It is defined by a number of universal components, including oxidative stress, cellular response to DNA damage, unfolded protein response to mitochondrial and endoplasmic reticulum stress, changes in autophagy, inflammasome formation, non-coding RNA response, formation of an inducible network of signaling pathways, and epigenetic changes. The presence of an inducible receptor and secretory phenotype in many cells is the cause of tissue pro-inflammatory stress. The key phenomenon determining the occurrence of a classical inflammatory focus is the microvascular inflammatory response (exudation, leukocyte migration to the alteration zone). This same reaction at the systemic level leads to the development of life-critical systemic inflammation. From this standpoint, we can characterize the common mechanisms of pathologies that differ in their clinical appearance. The division of inflammation into alternative variants has deep evolutionary roots. Evolutionary aspects of inflammation are also described in the review. The aim of the review is to provide theoretical arguments for the need for an up-to-date theory of the relationship between key human pathological processes based on the integrative role of the molecular mechanisms of cellular and tissue pro-inflammatory stress.

A Pro-Inflammatory Signature Constitutively Activated in Monogenic Autoinflammatory Diseases

Autoinflammatory diseases (AIDs) are disorders characterised by recurrent inflammatory episodes in charge of different organs with no apparent involvement of autoantibodies or antigen-specific T lymphocytes. Few common clinical features have been identified among all monogenic AIDs (mAIDs), while the search for a common molecular pattern is still ongoing. The aim of this study was to increase knowledge on the inflammatory pathways in the development of mAIDs in order to identify possible predictive or diagnostic biomarkers for each disease and to develop future preventive and therapeutic strategies. Using protein array-based systems, we evaluated two signalling pathways known to be involved in inflammation and a wide range of inflammatory mediators (pro-inflammatory cytokines and chemokines) in a cohort of 23 patients affected by different mAIDs, as FMF, TRAPS, MKD, Blau syndrome (BS), and NLRP12D. Overall, we observed upregulation of multiple signalling pathway intermediates at protein levels in mAIDs patients’ PBMCs, compared with healthy controls, with significant differences also between patients. FMF, TRAPS, and BS presented also peculiar activations of inflammatory pathways that can distinguish them. MAPK pathway activation, however, seems to be a common feature. The serum level of cytokines and chemokines produced clear differences between patients with distinct diseases, which can help distinguish each autoinflammatory disease. The FMF cytokine production profile appears broader than that of TRAPS, which, in turn, has higher cytokine levels than BS. Our findings suggest an ongoing subclinical inflammation related to the abnormal and constitutive signalling pathways and define an elevated inflammatory cytokine signature. Moreover, the upregulation of Th17-related cytokines emphasises the important role for Th17 and/or Th17-like cells also in monogenic AIDs.