Interleukin-6 neutralization ameliorates symptoms in prematurely aged mice

Aging and Inflammation

Aging can be conceptualized as the progressive disequilibrium between stochastic damage accumulation and resilience mechanisms that continuously repair that damage, which eventually cause the development of chronic disease, frailty, and death. The immune system is at the forefront of these resilience mechanisms. Indeed, aging is associated with persistent activation of the immune system, witnessed by a high circulating level of inflammatory markers and activation of immune cells in the circulation and in tissue, a condition called "inflammaging." Like aging, inflammaging is associated with increased risk of many age-related pathologies and disabilities, as well as frailty and death. Herein we discuss recent advances in the understanding of the mechanisms leading to inflammaging and the intrinsic dysregulation of the immune function that occurs with aging. We focus on the underlying mechanisms of chronic inflammation, in particular the role of NF-κB and recent studies targeting proinflammatory mediators. We further explore the dysregulation of the immune response with age and immunosenescence as an important mechanistic immune response to acute stressors. We examine the role of the gastrointestinal microbiome, age-related dysbiosis, and the integrated stress response in modulating the inflammatory "response" to damage accumulation and stress. We conclude by focusing on the seminal question of whether reducing inflammation is useful and the results of related clinical trials. In summary, we propose that inflammation may be viewed both as a clinical biomarker of the failure of resilience mechanisms and as a causal factor in the rising burden of disease and disabilities with aging. The fact that inflammation can be reduced through nonpharmacological interventions such as diet and exercise suggests that a life course approach based on education may be a successful strategy to increase the health span with few adverse consequences.

Mitophagy defect mediates the aging-associated hallmarks in Hutchinson-Gilford progeria syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a rare and fatal disease manifested by premature aging and aging-related phenotypes, making it a disease model for aging. The cellular machinery mediating age-associated phenotypes in HGPS remains largely unknown, resulting in limited therapeutic targets for HGPS. In this study, we showed that mitophagy defects impaired mitochondrial function and contributed to cellular markers associated with aging in mesenchymal stem cells derived from HGPS patients (HGPS-MSCs). Mechanistically, we discovered that mitophagy affected the aging-associated phenotypes of HGPS-MSCs by inhibiting the STING-NF-ĸB pathway and the downstream transcription of senescence-associated secretory phenotypes (SASPs). Furthermore, by utilizing UMI-77, an effective mitophagy inducer, we showed that mitophagy induction alleviated aging-associated phenotypes in HGPS and naturally aged mice. Collectively, our results uncovered that mitophagy defects mediated the aging-associated markers in HGPS, highlighted the function of mitochondrial homeostasis in HGPS progression, and suggested mitophagy as an intervention target for HGPS and aging.

Doxycycline decelerates aging in progeria mice

Beyond the antimicrobial activity, doxycycline (DOX) exhibits longevity-promoting effect in nematodes, while its effect on mammals is unclear. Here, we applied a mouse model of Hutchinson-Gilford progeria syndrome (HGPS), Zmpste24 knockout (KO) mice, and analyzed the antiaging effect of DOX. We found that the DOX treatment prolongs lifespan and ameliorates progeroid features of Zmpste24 KO mice, including the decline of body and tissue weight, exercise capacity and cortical bone density, and the shortened colon length. DOX treatment alleviates the abnormal nuclear envelope in multiple tissues, and attenuates cellular senescence and cell death of Zmpste24 KO and HGPS fibroblasts. DOX downregulates the level of proinflammatory IL6 in both serum and tissues. Moreover, the elevated α-tubulin (K40) acetylation mediated by NAT10 in progeria, is rescued by DOX treatment in the aorta tissues in Zmpste24 KO mice and fibroblasts. Collectively, our study uncovers that DOX can decelerate aging in progeria mice via counteracting IL6 expression and NAT10-mediated acetylation of α-tubulin.

Identification of STAT3 as a biomarker for cellular senescence in liver fibrosis: A bioinformatics and experimental validation study

BACKGROUND

Cellular senescence is associated with a dysregulated inflammatory response, which is an important driver of the development of liver fibrosis (LF). This study aimed to investigate the effect of cellular senescence on LF and identify potential key biomarkers through bioinformatics analysis combined with validation experiments in vivo and in vitro.

METHODS

The Gene Expression Omnibus (GEO) database and GeneCards database were used to download the LF dataset and the aging-related gene set, respectively. Functional enrichment analysis of differential genes was then performed using GO and KEGG. Hub genes were further screened using Cytoscape's cytoHubba. Diagnostic values for hub genes were evaluated with a receiver operating characteristic (ROC) curve. Next, CIBERSORTx was used to estimate immune cell types and ratios. Finally, in vivo and in vitro experiments validated the results of the bioinformatics analysis. Moreover, molecular docking was used to simulate drug-gene interactions.

RESULTS

A total of 44 aging-related differentially expressed genes (AgDEGs) were identified, and enrichment analysis showed that these genes were mainly enriched in inflammatory and immune responses. PPI network analysis identified 6 hub AgDEGs (STAT3, TNF, MMP9, CD44, TGFB1, and TIMP1), and ROC analysis showed that they all have good diagnostic value. Immune infiltration suggested that hub AgDEGs were significantly associated with M1 macrophages or other immune cells. Notably, STAT3 was positively correlated with α-SMA, COL1A1, IL-6 and IL-1β, and was mainly expressed in hepatocytes (HCs). Validation experiments showed that STAT3 expression was upregulated and cellular senescence was increased in LF mice. A co-culture system of HCs and hepatic stellate cells (HSCs) further revealed that inhibiting STAT3 reduced HCs senescence and suppressed HSCs activation. In addition, molecular docking revealed that STAT3 was a potential drug therapy target.

CONCLUSIONS

STAT3 may be involved in HCs senescence and promote HSCs activation, which in turn leads to the development of LF. Our findings suggest that STAT3 could be a potential biomarker for LF.

Mineralocorticoid Receptor Antagonism Prevents Type 2 Familial Partial Lipodystrophy Brown Adipocyte Dysfunction

Type-2 Familial Partial Lipodystrophy (FPLD2), a rare lipodystrophy caused by LMNA mutations, is characterized by a loss of subcutaneous fat from the trunk and limbs and excess accumulation of adipose tissue in the neck and face. Several studies have reported that the mineralocorticoid receptor (MR) plays an essential role in adipose tissue differentiation and functionality. We previously showed that brown preadipocytes isolated from a FPLD2 patient's neck aberrantly differentiate towards the white lineage. As this condition may be related to MR activation, we suspected altered MR dynamics in FPLD2. Despite cytoplasmic MR localization in control brown adipocytes, retention of MR was observed in FPLD2 brown adipocyte nuclei. Moreover, overexpression of wild-type or mutated prelamin A caused GFP-MR recruitment to the nuclear envelope in HEK293 cells, while drug-induced prelamin A co-localized with endogenous MR in human preadipocytes. Based on in silico analysis and in situ protein ligation assays, we could suggest an interaction between prelamin A and MR, which appears to be inhibited by mineralocorticoid receptor antagonism. Importantly, the MR antagonist spironolactone redirected FPLD2 preadipocyte differentiation towards the brown lineage, avoiding the formation of enlarged and dysmorphic lipid droplets. Finally, beneficial effects on brown adipose tissue activity were observed in an FPLD2 patient undergoing spironolactone treatment. These findings identify MR as a new lamin A interactor and a new player in lamin A-linked lipodystrophies.

Non-Genomic Hallmarks of Aging-The Review

Aging is a natural, gradual, and inevitable process associated with a series of changes at the molecular, cellular, and tissue levels that can lead to an increased risk of many diseases, including cancer. The most significant changes at the genomic level (DNA damage, telomere shortening, epigenetic changes) and non-genomic changes are referred to as hallmarks of aging. The hallmarks of aging and cancer are intertwined. Many studies have focused on genomic hallmarks, but non-genomic hallmarks are also important and may additionally cause genomic damage and increase the expression of genomic hallmarks. Understanding the non-genomic hallmarks of aging and cancer, and how they are intertwined, may lead to the development of approaches that could influence these hallmarks and thus function not only to slow aging but also to prevent cancer. In this review, we focus on non-genomic changes. We discuss cell senescence, disruption of proteostasis, deregualation of nutrient sensing, dysregulation of immune system function, intercellular communication, mitochondrial dysfunction, stem cell exhaustion and dysbiosis.

The Activation of JAK/STAT3 Signaling and the Complement System Modulate Inflammation in the Primary Human Dermal Fibroblasts of PXE Patients

Previous studies revealed a link between inflammation and overactivation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling in syndromes associated with aging. Pseudoxanthoma elasticum (PXE), a rare autosomal-recessive disorder, arises from mutations in ATP-binding cassette subfamily C member 6 (ABCC6). On a molecular level, PXE shares similarities with Hutchinson-Gilford progeria syndrome, such as increased activity of senescence-associated- beta-galactosidase or high expression of inflammatory factors. Thus, this study's aim was the evaluation of activated STAT3 and the influence of JAK1/2-inhibitor baricitinib (BA) on inflammatory processes such as the complement system in PXE. Analysis of activation of STAT3 was performed by immunofluorescence and Western blot, while inflammatory processes and complement system factors were determined based on mRNA expression and protein level. Our results assume overactivation of JAK/STAT3 signaling, increased expression levels of several complement factors and high C3 protein concentration in the sera of PXE patients. Supplementation with BA reduces JAK/STAT3 activation and partly reduces inflammation as well as the gene expression of complement factors belonging to the C1 complex and C3 convertase in PXE fibroblasts. Our results indicate a link between JAK/STAT3 signaling and complement activation contributing to the proinflammatory phenotype in PXE fibroblasts.

Progerin, an Aberrant Spliced Form of Lamin A, Is a Potential Therapeutic Target for HGPS

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare genetic disorder caused by the mutant protein progerin, which is expressed by the abnormal splicing of the LMNA gene. HGPS affects systemic levels, with the exception of cognition or brain development, in children, showing that cellular aging can occur in the short term. Studying progeria could be useful in unraveling the causes of human aging (as well as fatal age-related disorders). Elucidating the clear cause of HGPS or the development of a therapeutic medicine could improve the quality of life and extend the survival of patients. This review aimed to (i) briefly describe how progerin was discovered as the causative agent of HGPS, (ii) elucidate the puzzling observation of the absence of primary neurological disease in HGPS, (iii) present several studies showing the deleterious effects of progerin and the beneficial effects of its inhibition, and (iv) summarize research to develop a therapy for HGPS and introduce clinical trials for its treatment.

Bone dysplasia in Hutchinson-Gilford progeria syndrome is associated with dysregulated differentiation and function of bone cell populations

Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disorder affecting tissues of mesenchymal origin. Most individuals with HGPS harbor a de novo c.1824C > T (p.G608G) mutation in the gene encoding lamin A (LMNA), which activates a cryptic splice donor site resulting in production of the toxic "progerin" protein. Clinical manifestations include growth deficiency, lipodystrophy, sclerotic dermis, cardiovascular defects, and bone dysplasia. Here we utilized the LmnaG609G knock-in (KI) mouse model of HGPS to further define mechanisms of bone loss associated with normal and premature aging disorders. Newborn skeletal staining of KI mice revealed altered rib cage shape and spinal curvature, and delayed calvarial mineralization with increased craniofacial and mandibular cartilage content. MicroCT analysis and mechanical testing of adult femurs indicated increased fragility associated with reduced bone mass, recapitulating the progressive bone deterioration that occurs in HGPS patients. We investigated mechanisms of bone loss in KI mice at the cellular level in bone cell populations. Formation of wild-type and KI osteoclasts from marrow-derived precursors was inhibited by KI osteoblast-conditioned media in vitro, suggesting a secreted factor(s) responsible for decreased osteoclasts on KI trabecular surfaces in vivo. Cultured KI osteoblasts exhibited abnormal differentiation characterized by reduced deposition and mineralization of extracellular matrix with increased lipid accumulation compared to wild-type, providing a mechanism for altered bone formation. Furthermore, quantitative analyses of KI transcripts confirmed upregulation of adipogenic genes both in vitro and in vivo. Thus, osteoblast phenotypic plasticity, inflammation and altered cellular cross-talk contribute to abnormal bone formation in HGPS mice.

"Bone-SASP" in Skeletal Aging

Senescence is a complex cell state characterized by stable cell cycle arrest and a unique secretory pattern known as the senescence-associated secretory phenotype (SASP). The SASP factors, which are heterogeneous and tissue specific, normally include chemokines, cytokines, growth factors, adhesion molecules, and lipid components that can lead to multiple age-associated disorders by eliciting local and systemic consequences. The skeleton is a highly dynamic organ that changes constantly in shape and composition. Senescent cells in bone and bone marrow produce diverse SASP factors that induce alterations of the skeleton through paracrine effects. Herein, we refer to bone cell-associated SASP as "bone-SASP." In this review, we describe current knowledge of cellular senescence and SASP, focusing on the role of senescent cells in mediating bone pathologies during natural aging and premature aging syndromes. We also summarize the role of cellular senescence and the bone-SASP in glucocorticoids-induced bone damage. In addition, we discuss the role of bone-SASP in the development of osteoarthritis, highlighting the mechanisms by which bone-SASP drives subchondral bone changes in metabolic syndrome-associated osteoarthritis.

Inflammation and aging: signaling pathways and intervention therapies

Aging is characterized by systemic chronic inflammation, which is accompanied by cellular senescence, immunosenescence, organ dysfunction, and age-related diseases. Given the multidimensional complexity of aging, there is an urgent need for a systematic organization of inflammaging through dimensionality reduction. Factors secreted by senescent cells, known as the senescence-associated secretory phenotype (SASP), promote chronic inflammation and can induce senescence in normal cells. At the same time, chronic inflammation accelerates the senescence of immune cells, resulting in weakened immune function and an inability to clear senescent cells and inflammatory factors, which creates a vicious cycle of inflammation and senescence. Persistently elevated inflammation levels in organs such as the bone marrow, liver, and lungs cannot be eliminated in time, leading to organ damage and aging-related diseases. Therefore, inflammation has been recognized as an endogenous factor in aging, and the elimination of inflammation could be a potential strategy for anti-aging. Here we discuss inflammaging at the molecular, cellular, organ, and disease levels, and review current aging models, the implications of cutting-edge single cell technologies, as well as anti-aging strategies. Since preventing and alleviating aging-related diseases and improving the overall quality of life are the ultimate goals of aging research, our review highlights the critical features and potential mechanisms of inflammation and aging, along with the latest developments and future directions in aging research, providing a theoretical foundation for novel and practical anti-aging strategies.

Impact of Combined Baricitinib and FTI Treatment on Adipogenesis in Hutchinson-Gilford Progeria Syndrome and Other Lipodystrophic Laminopathies

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disease that causes premature aging symptoms, such as vascular diseases, lipodystrophy, loss of bone mineral density, and alopecia. HGPS is mostly linked to a heterozygous and de novo mutation in the LMNA gene (c.1824 C > T; p.G608G), resulting in the production of a truncated prelamin A protein called "progerin". Progerin accumulation causes nuclear dysfunction, premature senescence, and apoptosis. Here, we examined the effects of baricitinib (Bar), an FDA-approved JAK/STAT inhibitor, and a combination of Bar and lonafarnib (FTI) treatment on adipogenesis using skin-derived precursors (SKPs). We analyzed the effect of these treatments on the differentiation potential of SKPs isolated from pre-established human primary fibroblast cultures. Compared to mock-treated HGPS SKPs, Bar and Bar + FTI treatments improved the differentiation of HGPS SKPs into adipocytes and lipid droplet formation. Similarly, Bar and Bar + FTI treatments improved the differentiation of SKPs derived from patients with two other lipodystrophic diseases: familial partial lipodystrophy type 2 (FPLD2) and mandibuloacral dysplasia type B (MADB). Overall, the results show that Bar treatment improves adipogenesis and lipid droplet formation in HGPS, FPLD2, and MADB, indicating that Bar + FTI treatment might further ameliorate HGPS pathologies compared to lonafarnib treatment alone.

Simultaneous neutralization of TGF-β and IL-6 attenuates Staphylococcus aureus-induced arthritic inflammation through differential modulation of splenic and synovial macrophages

Septic arthritis is a joint disease caused by Staphylococcus aureus. Different macrophage populations contribute in various ways to control blood-borne infections and induce inflammatory responses. Macrophage tissue-resident niche is necessary for the suppression of chronic inflammation and may contribute to the pathogenesis of septic arthritis. Thus, to obtain a resolution of the disease and restoration of synovial homeostasis, it needs the activation of macrophages that further regulate the inflammatory consequences. The aim of this study was to find out the mechanism by which neutralization of transforming growth factor-beta (TGF-β) and/or interleukin (IL)-6 after induction of septic arthritis could alter the specific macrophage responses in spleen and synovial joints via different cytokines (osteoprotegerin (OPG), osteopontin (OPN), IL-10, IL-12 and CXCL8) cross-talking, and how the response could be modulated by reactive oxygen species vs antioxidant enzyme activities. Dual neutralization of TGF-β and IL-6 is notably effective in eliciting splenic and synovial tissue-resident macrophage responses. Synovial macrophage-derived IL-10 can elicit protection against septic arthritis via regulating receptor-activated nuclear factor Kappa-B ligand (RANKL)/OPG interaction. They also reduced oxidative stress by increasing the activity of antioxidant enzymes including SOD and catalase. Histopathological analysis revealed that dual neutralization of TGF-β and IL-6 prevented bone destruction and osteoclastic activity in septic arthritis by promoting the differential functional response of the splenic and synovial macrophages. Additionally, the macrophage-derived IL-10 can elicit protection against S. aureus-induced septic arthritis via regulating RANKL/OPG interaction. Further studies on STAT3 and STAT4 are needed for the understanding of such cross-talking in resident macrophages of arthritic mice.

Vascular smooth muscle cell aging: Insights from Hutchinson-Gilford progeria syndrome

Vascular smooth muscle cells (VSMCs) constitute the principal cellular component of the medial layer of arteries and are responsible for vessel contraction and relaxation in response to blood flow. Alterations in VSMCs can hinder vascular system function, leading to vascular stiffness, calcification and atherosclerosis, which in turn may result in life-threatening complications. Pathological changes in VSMCs typically correlate with chronological age; however, there are certain conditions and diseases, such as Hutchinson-Gilford progeria syndrome (HGPS), that can accelerate this process, resulting in premature vascular aging. HGPS is a rare genetic disorder characterized by severe VSMC loss, accelerated atherosclerosis and death from myocardial infarction or stroke during the adolescence. Because experiments with mouse models have demonstrated that alterations in VSMCs are responsible for early atherosclerosis in HGPS, studies on this disease can provide insights into the mechanisms of vascular aging and assess the relative contribution of VSMCs to this process.

Progerin induces a phenotypic switch in vascular smooth muscle cells and triggers replication stress and an aging-associated secretory signature

Hutchinson-Gilford progeria syndrome is a premature aging disease caused by LMNA gene mutation and the production of a truncated prelamin A protein "progerin" that elicits cellular and organismal toxicity. Progerin accumulates in the vasculature, being especially detrimental for vascular smooth muscle cells (VSMC). Vessel stiffening and aortic atherosclerosis in HGPS patients are accompanied by VSMC depletion in the medial layer, altered extracellular matrix (ECM), and thickening of the adventitial layer. Mechanisms whereby progerin causes massive VSMC loss and vessel alterations remain poorly understood. Mature VSMC retain phenotypic plasticity and can switch to a synthetic/proliferative phenotype. Here, we show that progerin expression in human and mouse VSMC causes a switch towards the synthetic phenotype. This switch elicits some level of replication stress in normal cells, which is exacerbated in the presence of progerin, leading to telomere fragility, genomic instability, and ultimately VSMC death. Calcitriol prevents replication stress, telomere fragility, and genomic instability, reducing VSMC death. In addition, RNA-seq analysis shows induction of a profibrotic and pro-inflammatory aging-associated secretory phenotype upon progerin expression in human primary VSMC. Our data suggest that phenotypic switch-induced replication stress might be an underlying cause of VSMC loss in progeria, which together with loss of contractile features and gain of profibrotic and pro-inflammatory signatures contribute to vascular stiffness in HGPS.

The role of prelamin A post-translational maturation in stress response and 53BP1 recruitment

Lamin A is a main constituent of the nuclear lamina and contributes to nuclear shaping, mechano-signaling transduction and gene regulation, thus affecting major cellular processes such as cell cycle progression and entry into senescence, cellular differentiation and stress response. The role of lamin A in stress response is particularly intriguing, yet not fully elucidated, and involves prelamin A post-translational processing. Here, we propose prelamin A as the tool that allows lamin A plasticity during oxidative stress response and permits timely 53BP1 recruitment to DNA damage foci. We show that while PCNA ubiquitination, p21 decrease and H2AX phosphorylation occur soon after stress induction in the absence of prelamin A, accumulation of non-farnesylated prelamin A follows and triggers recruitment of 53BP1 to lamin A/C complexes. Then, the following prelamin A processing steps causing transient accumulation of farnesylated prelamin A and maturation to lamin A reduce lamin A affinity for 53BP1 and favor its release and localization to DNA damage sites. Consistent with these observations, accumulation of prelamin A forms in cells under basal conditions impairs histone H2AX phosphorylation, PCNA ubiquitination and p21 degradation, thus affecting the early stages of stress response. As a whole, our results are consistent with a physiological function of prelamin A modulation during stress response aimed at timely recruitment/release of 53BP1 and other molecules required for DNA damage repair. In this context, it becomes more obvious how farnesylated prelamin A accumulation to toxic levels alters timing of DNA damage signaling and 53BP1 recruitment, thus contributing to cellular senescence and accelerated organismal aging as observed in progeroid laminopathies.

The hormetic and hermetic role of IL-6

Interleukin-6 is a pleiotropic cytokine regulating different tissues and organs in diverse and sometimes discrepant ways. The dual and sometime hermetic nature of IL-6 action has been highlighted in several contexts and can be explained by the concept of hormesis, in which beneficial or toxic effects can be induced by the same molecule depending on the intensity, persistence, and nature of the stimulation. According with hormesis, a low and/or controlled IL-6 release is associated with anti-inflammatory, antioxidant, and pro-myogenic actions, whereas increased systemic levels of IL-6 can induce pro-inflammatory, pro-oxidant and pro-fibrotic responses. However, many aspects regarding the multifaceted action of IL-6 and the complex nature of its signal transduction remains to be fully elucidated. In this review we collect mechanistic insight into the molecular networks contributing to normal or pathologic changes during advancing age and in chronic diseases. We point out the involvement of IL-6 deregulation in aging-related diseases, dissecting the hormetic action of this key mediator in different tissues, with a special focus on skeletal muscle. Since IL-6 can act as an enhancer of detrimental factor associated with both aging and pathologic conditions, such as chronic inflammation and oxidative stress, this cytokine could represent a "Gerokine", a determinant of the switch from physiologic aging to age-related diseases.

In Vitro Characterization of Doxorubicin-Mediated Stress-Induced Premature Senescence in Human Chondrocytes

Accumulation of senescent chondrocytes is thought to drive inflammatory processes and subsequent cartilage degeneration in age-related as well as posttraumatic osteoarthritis (OA). However, the underlying mechanisms of senescence and consequences on cartilage homeostasis are not completely understood so far. Therefore, suitable in vitro models are needed to study chondrocyte senescence. In this study, we established and evaluated a doxorubicin (Doxo)-based model of stress-induced premature senescence (SIPS) in human articular chondrocytes (hAC). Cellular senescence was determined by the investigation of various senescence associated (SA) hallmarks including β-galactosidase activity, expression of p16, p21, and SA secretory phenotype (SASP) markers (IL-6, IL-8, MMP-13), the presence of urokinase-type plasminogen activator receptor (uPAR), and cell cycle arrest. After seven days, Doxo-treated hAC displayed a SIPS-like phenotype, characterized by excessive secretion of SASP factors, enhanced uPAR-positivity, decreased proliferation rate, and increased β-galactosidase activity. This phenotype was proven to be stable seven days after the removal of Doxo. Moreover, Doxo-treated hAC exhibited increased granularity and flattened or fibroblast-like morphology. Further analysis implies that Doxo-mediated SIPS was driven by oxidative stress as demonstrated by increased ROS levels and NO release. Overall, we provide novel insights into chondrocyte senescence and present a suitable in vitro model for further studies.

Endothelial and systemic upregulation of miR-34a-5p fine-tunes senescence in progeria

Endothelial defects significantly contribute to cardiovascular pathology in the premature aging disease Hutchinson-Gilford progeria syndrome (HGPS). Using an endothelium-specific progeria mouse model, we identify a novel, endothelium-specific microRNA (miR) signature linked to the p53-senescence pathway and a senescence-associated secretory phenotype (SASP). Progerin-expressing endothelial cells exert profound cell-non-autonomous effects initiating senescence in non-endothelial cell populations and causing immune cell infiltrates around blood vessels. Comparative miR expression analyses revealed unique upregulation of senescence-associated miR34a-5p in endothelial cells with strong accumulation at atheroprone aortic arch regions but also, in whole cardiac- and lung tissues as well as in the circulation of progeria mice. Mechanistically, miR34a-5p knockdown reduced not only p53 levels but also late-stage senescence regulator p16 with no effect on p21 levels, while p53 knockdown reduced miR34a-5p and partially rescued p21-mediated cell cycle inhibition with a moderate effect on SASP. These data demonstrate that miR34a-5p reinforces two separate senescence regulating branches in progerin-expressing endothelial cells, the p53- and p16-associated pathways, which synergistically maintain a senescence phenotype that contributes to cardiovascular pathology. Thus, the key function of circulatory miR34a-5p in endothelial dysfunction-linked cardiovascular pathology offers novel routes for diagnosis, prognosis and treatment for cardiovascular aging in HGPS and potentially geriatric patients.

Pro-inflammatory cytokines as emerging molecular determinants in cardiolaminopathies

Mutations in Lamin A/C gene (lmna) cause a wide spectrum of cardiolaminopathies strictly associated with significant deterioration of the electrical and contractile function of the heart. Despite the continuous flow of biomedical evidence, linking cardiac inflammation to heart remodelling in patients harbouring lmna mutations is puzzling. Therefore, we profiled 30 serum cytokines/chemokines in patients belonging to four different families carrying pathogenic lmna mutations segregating with cardiac phenotypes at different stages of severity (n = 19) and in healthy subjects (n = 11). Regardless lmna mutation subtype, high levels of circulating granulocyte colony‐stimulating factor (G‐CSF) and interleukin 6 (IL‐6) were found in all affected patients’ sera. In addition, elevated levels of Interleukins (IL) IL‐1Ra, IL‐1β IL‐4, IL‐5 and IL‐8 and the granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) were measured in a large subset of patients associated with more aggressive clinical manifestations. Finally, the expression of the pro‐inflammatory 70 kDa heat shock protein (Hsp70) was significantly increased in serum exosomes of patients harbouring the lmna mutation associated with the more severe phenotype. Overall, the identification of patient subsets with overactive or dysregulated myocardial inflammatory responses could represent an innovative diagnostic, prognostic and therapeutic tool against Lamin A/C cardiomyopathies.

Cell and Cell-Free Therapies to Counteract Human Premature and Physiological Aging: MSCs Come to Light

The progressive loss of the regenerative potential of tissues is one of the most obvious consequences of aging, driven by altered intercellular communication, cell senescence and niche-specific stem cell exhaustion, among other drivers. Mesenchymal tissues, such as bone, cartilage and fat, which originate from mesenchymal stem cell (MSC) differentiation, are especially affected by aging. Senescent MSCs show limited proliferative capacity and impairment in key defining features: their multipotent differentiation and secretory abilities, leading to diminished function and deleterious consequences for tissue homeostasis. In the past few years, several interventions to improve human healthspan by counteracting the cellular and molecular consequences of aging have moved closer to the clinic. Taking into account the MSC exhaustion occurring in aging, advanced therapies based on the potential use of young allogeneic MSCs and derivatives, such as extracellular vesicles (EVs), are gaining attention. Based on encouraging pre-clinical and clinical data, this review assesses the strong potential of MSC-based (cell and cell-free) therapies to counteract age-related consequences in both physiological and premature aging scenarios. We also discuss the mechanisms of action of these therapies and the possibility of enhancing their clinical potential by exposing MSCs to niche-relevant signals.

Aging, Cell Senescence, the Pathogenesis and Targeted Therapies of Osteoarthritis

Osteoarthritis (OA) is a chronic, debilitating joint disease characterized by progressive destruction of articular cartilage. For a long time, OA has been considered as a degenerative disease, while recent observations indicate the mechanisms responsible for the pathogenesis of OA are multifaceted. Aging is a key factor in its development. Current treatments are palliative and no disease modifying anti-osteoarthritis drugs (DMOADs) are available. In addition to articular cartilage degradation, cellular senescence, synovial inflammation, and epigenetic alterations may all have a role in its formation. Accumulating data demonstrate a clear relationship between the senescence of articular chondrocytes and OA formation and progression. Inhibition of cell senescence may help identify new agents with the properties of DMOADs. Several anti-cellular senescence strategies have been proposed and these include sirtuin-activating compounds (STACs), senolytics, and senomorphics drugs. These agents may selectively remove senescent cells or ameliorate their harmful effects. The results from preclinical experiments and clinical trials are inspiring. However, more studies are warranted to confirm their efficacy, safety profiles and adverse effects of these agents.

Decoding and rejuvenating human ageing genomes: Lessons from mosaic chromosomal alterations

One of the most curious findings emerged from genome-wide studies over the last decade was that genetic mosaicism is a dominant feature of human ageing genomes. The clonal dominance of genetic mosaicism occurs preceding the physiological and physical ageing and associates with propensity for diseases including cancer, Alzheimer's disease, cardiovascular disease and diabetes. These findings are revolutionizing the ways biologists thinking about health and disease pathogenesis. Among all mosaic mutations in ageing genomes, mosaic chromosomal alterations (mCAs) have the most significant functional consequences because they can produce intercellular genomic variations simultaneously involving dozens to hundreds or even thousands genes, and therefore have most profound effects in human ageing and disease etiology. Here, we provide a comprehensive picture of the landscapes, causes, consequences and rejuvenation of mCAs at multiple scales, from cell to human population, by reviewing data from cytogenetic, genetic and genomic studies in cells, animal models (fly and mouse) and, more frequently, large-cohort populations. A detailed decoding of ageing genomes with a focus on mCAs may yield important insights into the genomic architecture of human ageing, accelerate the risk stratification of age-related diseases (particularly cancers) and development of novel targets and strategies for delaying or rejuvenating human (genome) ageing.

Impact of Progerin Expression on Adipogenesis in Hutchinson-Gilford Progeria Skin-Derived Precursor Cells

Hutchinson–Gilford progeria syndrome (HGPS) is a segmental premature aging disease caused by a mutation in LMNA. The mutation generates a truncated and farnesylated form of prelamin A, called progerin. Affected individuals develop several features of normal aging, including lipodystrophy caused by the loss of general subcutaneous fat. To determine whether premature cellular senescence is responsible for the altered adipogenesis in patients with HGPS, we evaluated the differentiation of HGPS skin-derived precursor stem cells (SKPs) into adipocytes. The SKPs were isolated from primary human HGPS and normal fibroblast cultures, with senescence of 5 and 30%. We observed that the presence of high numbers of senescent cells reduced SKPs’ adipogenic differentiation potential. Treatment with baricitinib, a JAK–STAT inhibitor, ameliorated the ability of HGPS SKPs to differentiate into adipocytes. Our findings suggest that the development of lipodystrophy in patients with HGPS may be associated with an increased rate of cellular senescence and chronic inflammation.

The Most Severe Paradigm of Early Cardiovascular Disease: Hutchinson-Gilford Progeria. Focus on the Role of Oxidative Stress

Oxidative stress (OS) is one of the most frequently recognized causes of ageing. Telomere erosion, defects in the DNA damage response and alterations in the nuclear architecture are also associated with premature ageing. The most severe premature ageing syndrome, Hutchinson-Gilford progeria syndrome (HGPS) is associated with alterations in nuclear shape resulting in the deregulation of lamin A/C. In this review we describe emerging data reporting the role of OS and antioxidant defence in progeroid syndromes focusing on HGPS. We explore precise antioxidant defence mechanisms and related drugs that may create a potential path out of the woods in this disease. Pathways regulated by Nuclear factor E2 related factor (Nrf2), by Nuclear Factor kappa B (NF-kB), and related to the Unfolded Protein Response (UPR) and Endoplasmic Reticulum (ER) stress are under investigation in HGPS patients for which the goal is a significant lifespan extension in particular by postponing atherosclerosis-related complications.

Molecular and Cellular Mechanisms Driving Cardiovascular Disease in Hutchinson-Gilford Progeria Syndrome: Lessons Learned from Animal Models

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disease that recapitulates many symptoms of physiological aging and precipitates death. Patients develop severe vascular alterations, mainly massive vascular smooth muscle cell loss, vessel stiffening, calcification, fibrosis, and generalized atherosclerosis, as well as electrical, structural, and functional anomalies in the heart. As a result, most HGPS patients die of myocardial infarction, heart failure, or stroke typically during the first or second decade of life. No cure exists for HGPS, and therefore it is of the utmost importance to define the mechanisms that control disease progression in order to develop new treatments to improve the life quality of patients and extend their lifespan. Since the discovery of the HGPS-causing mutation, several animal models have been generated to study multiple aspects of the syndrome and to analyze the contribution of different cell types to the acquisition of the HGPS-associated cardiovascular phenotype. This review discusses current knowledge about cardiovascular features in HGPS patients and animal models and the molecular and cellular mechanisms through which progerin causes cardiovascular disease.

The progeria research foundation 10th international scientific workshop; researching possibilities, ExTENding lives - webinar version scientific summary

Progeria is an ultra-rare (prevalence 1 in 20 million), fatal, pediatric autosomal dominant premature aging disease caused by a mutation in the LMNA gene. This mutation results in accumulation of a high level of an aberrant form of the nuclear membrane protein, Lamin A. This aberrant protein, termed progerin, accumulates in many tissues and is responsible for the diverse array of disease phenotypes. Children die predominantly from premature atherosclerotic cardiovascular disease. The Progeria Research Foundation’s 10^th International Scientific Workshop took place via webinar on November 2 and 3, 2020. Participants from 30 countries joined in this new, virtual meeting format. Patient family presentations led the program, followed by updates on Progeria’s first-ever application for FDA drug approval as well as initial results from the only current Progeria clinical trial. This was followed by presentations of unpublished preclinical data on drugs in development targeting the disease-causing DNA mutation, the aberrant mRNA, progerin protein, and its downstream effector proteins. Tying bench to bedside, clinicians presented new discoveries on the natural history of disease to inform future clinical trial development and new Progeria aortic valve replacement procedures. The program engaged the Progeria research community as a single unit with a common goal – to treat and cure children with Progeria worldwide.