Methylene blue alleviates nuclear and mitochondrial abnormalities in progeria

Parishin Alleviates Pulmonary Fibrosis by Reducing CD38 Levels in Naturally Aging Mice

Parishin, a natural compound, has demonstrated significant potential in mitigating age-related phenotypes and improving outcomes in age-associated diseases. Given that aging is a major risk factor for numerous chronic conditions, including pulmonary fibrosis, we investigated parishin's effects on cellular senescence and lung health. In our study, we treated mouse lung epithelial cells with parishin and observed a reduction in cellular senescence markers alongside an upregulation of sirtuin 1 (SIRT1). Building on these in vitro findings, we administered parishin to naturally aged mice. The treatment resulted in decreased pulmonary fibrosis and reduced DNA damage in lung tissue. Notably, we found that parishin treatment led to a reduction in Cluster of differentiation 38 (CD38) levels, concomitant with an increase in SIRT1 expression. These findings indicate that parishin may enhance lung function in aged mice, suggesting its potential as a therapeutic agent for treating age-related pulmonary disorders.

MAM-STAT3-Driven Mitochondrial Ca+2 Upregulation Contributes to Immunosenescence in Type A Mandibuloacral Dysplasia Patients

Individuals with homozygous laminA/C p.R527C mutations manifest a severe form of Mandibuloacral dysplasia-(MAD) and exhibit overlapping progeroid symptoms, for which the underlying molecular pathology remains unknown. Herein, it is shown that MAD patients achieved inflammaging with different pro-inflammatory cytokines compared to progeria-(HGPS) patient. Characterization of MAD iPSC-derived Mesenchymal stem cells (MAD-iMSC) uncovers deregulated mitochondrial Ca+2 as the primary cause of inflammaging, mediated through inflammasome formation rather than the cGAS-STING pathway. Moreover, MAD-iMSCs extracellular vesicles (EVs) can also upregulate mitochondrial Ca+2 in healthy cells. This deregulated Ca+2 homeostasis is indirectly mediated by mitochondrial calcium mediator, signal transducer, and activator of transcription-3 (STAT3), situated on the mitochondrial associated membrane (MAM). Inflammaging is mitigated by various FDA-approved MAM-STAT3 upstream inhibitors, such as (Tocilizumab) or by correcting R527C mutation with CRISPR/CAS9. These results provide new insights into MAD disease and propose targeting defective mitochondrial Ca+2 homeostasis as a promising therapy for reversing immunosenescence.

Disorganized chromatin hierarchy and stem cell aging in a male patient of atypical laminopathy-based progeria mandibuloacral dysplasia type A

Studies of laminopathy-based progeria offer insights into aging-associated diseases and highlight the role of LMNA in chromatin organization. Mandibuloacral dysplasia type A (MAD) is a largely unexplored form of atypical progeria that lacks lamin A post-translational processing defects. Using iPSCs derived from a male MAD patient carrying homozygous LMNA p.R527C, premature aging phenotypes are recapitulated in multiple mesenchymal lineages, including mesenchymal stem cells (MSCs). Comparison with 26 human aging MSC expression datasets reveals that MAD-MSCs exhibit the highest similarity to senescent primary human MSCs. Lamina-chromatin interaction analysis reveals reorganization of lamina-associating domains (LADs) and repositioning of non-LAD binding peaks may contribute to the observed accelerated senescence. Additionally, 3D genome organization further supports hierarchical chromatin disorganization in MAD stem cells, alongside dysregulation of genes involved in epigenetic modification, stem cell fate maintenance, senescence, and geroprotection. Together, these findings suggest LMNA missense mutation is linked to chromatin alterations in an atypical progeroid syndrome.

Enhancing Cellular Homeostasis: Targeted Botanical Compounds Boost Cellular Health Functions in Normal and Premature Aging Fibroblasts

The human skin, the body's largest organ, undergoes continuous renewal but is significantly impacted by aging, which impairs its function and leads to visible changes. This study aimed to identify botanical compounds that mimic the anti-aging effects of baricitinib, a known JAK1/2 inhibitor. Through in silico screening of a botanical compound library, 14 potential candidates were identified, and 7 were further analyzed for their effects on cellular aging. The compounds were tested on both normal aged fibroblasts and premature aging fibroblasts derived from patients with Hutchinson-Gilford Progeria Syndrome (HGPS). Results showed that these botanical compounds effectively inhibited the JAK/STAT pathway, reduced the levels of phosphorylated STAT1 and STAT3, and ameliorated phenotypic changes associated with cellular aging. Treatments improved cell proliferation, reduced senescence markers, and enhanced autophagy without inducing cytotoxicity. Compounds, such as Resveratrol, Bisdemethoxycurcumin, Pinosylvin, Methyl P-Hydroxycinnamate, cis-Pterostilbene, and (+)-Gallocatechin, demonstrated significant improvements in both control and HGPS fibroblasts. These findings suggest that these botanical compounds have the potential to mitigate age-related cellular alterations, offering promising strategies for anti-aging therapies, particularly for skin health. Further in vivo studies are warranted to validate these results and explore their therapeutic applications.

Exosomes derived from hTERT-immortalized cells delay cellular senescence of human fibroblasts

hTERT gene therapies hold significant promise for treating age-related diseases. However, further research is required to address the challenges of delivery and ethical considerations. We hypothesized that exosomes derived from hTERT-immortalized cells could function similarly to hTERT gene therapies by maintaining telomere length and attenuating cellular senescence biomarkers. In this study, we overexpressed the hTERT gene in Human Foreskin Fibroblast-1 cells (HFF cells) to produce hTERT-immortalized HFF cells (hT-HFF cells). We then used exosomes derived from these hT-HFF cells to treat human fibroblasts, HFF cells. Our results demonstrated that these exosomes effectively attenuated biomarkers of cellular senescence in HFF cells. Furthermore, analysis revealed that hTERT mRNA was indeed packaged into the exosomes from hT-HFF cells. This mRNA was capable of elongating telomeres and delaying cellular senescence in HFF cells. Therefore, exosomes from hT-HFF cells show potential as a treatment for age-related diseases.

A functional aged human iPSC-cortical neuron model recapitulates Alzheimer's disease, senescence, and the response to therapeutics

INTRODUCTION

The degeneration of cortical layers is associated with cognitive decline in Alzheimer's disease (AD). Current therapies for AD are not disease-modifying, and, despite substantial efforts, research and development for AD has faced formidable challenges. In addition, cellular senescence has emerged as a significant contributor to therapy resistance.

METHODS

Human iPSC-derived cortical neurons were cultured on microelectrode arrays to measure long-term potentiation (LTP) noninvasively. Neurons were treated with pathogenic amyloid-β (Aβ) to analyze senescence and response to therapeutic molecules.

RESULTS

Microphysiological recordings revealed Aβ dampened cortical LTP activity and accelerated neuronal senescence. Aging neurons secreted inflammatory factors previously detected in brain, plasma, and cerebral spinal fluid of AD patients, in which drugs modulated senescence-related factors.

DISCUSSION

This platform measures and records neuronal LTP activity in response to Aβ and therapeutic molecules in real-time. Efficacy data from similar platforms have been accepted by the FDA for neurodegenerative diseases, expediting regulatory submissions.

HIGHLIGHTS

This work developed a progerontic model of amyloid-β (Aβ)-driven cortical degeneration. This work measured neuronal LTP and correlated function with aging biomarkers. Aβ is a driver of neuronal senescence and cortical degeneration. Molecules rescued neuronal function but did not halt Aβ-driven senescence. Therapeutic molecules modulated secretion of inflammatory factors by aging neurons.

Progerin mRNA expression in non-HGPS patients is correlated with widespread shifts in transcript isoforms

Hutchinson-Gilford Progeria Syndrome (HGPS) is a premature aging disease caused primarily by a C1824T mutation in LMNA. This mutation activates a cryptic splice donor site, producing a lamin variant called progerin. Interestingly, progerin has also been detected in cells and tissues of non-HGPS patients. Here, we investigated progerin expression using publicly available RNA-seq data from non-HGPS patients in the GTEx project. We found that progerin expression is present across all tissue types in non-HGPS patients and correlated with telomere shortening in the skin. Transcriptome-wide correlation analyses suggest that the level of progerin expression is correlated with switches in gene isoform expression patterns. Differential expression analyses show that progerin expression is correlated with significant changes in genes involved in splicing regulation and mitochondrial function. Interestingly, 5' splice sites whose use is correlated with progerin expression have significantly altered frequencies of consensus trinucleotides within the core 5' splice site. Furthermore, introns whose alternative splicing correlates with progerin have reduced GC content. Our study suggests that progerin expression in non-HGPS patients is part of a global shift in splicing patterns.

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.

Targeting mitochondrial dysfunction using methylene blue or mitoquinone to improve skeletal aging

Methylene blue (MB) is a well-established antioxidant that has been shown to improve mitochondrial function in both in vitro and in vivo settings. Mitoquinone (MitoQ) is a selective antioxidant that specifically targets mitochondria and effectively reduces the accumulation of reactive oxygen species. To investigate the effect of long-term administration of MB on skeletal morphology, we administered MB to aged (18 months old) female C57BL/J6 mice, as well as to adult male and female mice with a genetically diverse background (UM-HET3). Additionally, we used MitoQ as an alternative approach to target mitochondrial oxidative stress during aging in adult female and male UM-HET3 mice. Although we observed some beneficial effects of MB and MitoQ in vitro, the administration of these compounds in vivo did not alter the progression of age-induced bone loss. Specifically, treating 18-month-old female mice with MB for 6 or 12 months did not have an effect on age-related bone loss. Similarly, long-term treatment with MB from 7 to 22 months or with MitoQ from 4 to 22 months of age did not affect the morphology of cortical bone at the mid-diaphysis of the femur, trabecular bone at the distal-metaphysis of the femur, or trabecular bone at the lumbar vertebra-5 in UM-HET3 mice. Based on our findings, it appears that long-term treatment with MB or MitoQ alone, as a means to reduce skeletal oxidative stress, is insufficient to inhibit age-associated bone loss. This supports the notion that interventions solely with antioxidants may not provide adequate protection against skeletal aging.

p300 nucleocytoplasmic shuttling underlies mTORC1 hyperactivation in Hutchinson-Gilford progeria syndrome

The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth, metabolism and autophagy. Multiple pathways modulate mTORC1 in response to nutrients. Here we describe that nucleus-cytoplasmic shuttling of p300/EP300 regulates mTORC1 activity in response to amino acid or glucose levels. Depletion of these nutrients causes cytoplasm-to-nucleus relocalization of p300 that decreases acetylation of the mTORC1 component raptor, thereby reducing mTORC1 activity and activating autophagy. This is mediated by AMP-activated protein kinase-dependent phosphorylation of p300 at serine 89. Nutrient addition to starved cells results in protein phosphatase 2A-dependent dephosphorylation of nuclear p300, enabling its CRM1-dependent export to the cytoplasm to mediate mTORC1 reactivation. p300 shuttling regulates mTORC1 in most cell types and occurs in response to altered nutrients in diverse mouse tissues. Interestingly, p300 cytoplasm-nucleus shuttling is altered in cells from patients with Hutchinson-Gilford progeria syndrome. p300 mislocalization by the disease-causing protein, progerin, activates mTORC1 and inhibits autophagy, phenotypes that are normalized by modulating p300 shuttling. These results reveal how nutrients regulate mTORC1, a cytoplasmic complex, by shuttling its positive regulator p300 in and out of the nucleus, and how this pathway is misregulated in Hutchinson-Gilford progeria syndrome, causing mTORC1 hyperactivation and defective autophagy.

KAT8 functions in redox homeostasis and mitochondrial dynamics during mouse oocyte meiosis progression

As a histone acetyltransferase, lysine acetyltransferase 8 (KAT8) participates in diverse biological processes. However, the effect of KAT8 on oocyte maturation in mice remains unclear. In this study, we found that mouse oocytes overexpressing Kat8-OE induced maturation failure manifested reduced rates of GVBD and first polar body emission. In addition, immunostaining results revealed that Kat8 overexpressing oocytes showed inappropriate mitochondrial distribution patterns, overproduction of reactive oxygen species (ROS), accumulation of phosphorylated γH2AX, hyperacetylation of α-tubulin, and severely disrupted spindle/chromosome organization. Moreover, we revealed that Kat8 overexpression induced a decline in SOD1 proteins and KAT8's interaction with SOD1 in mouse ovaries via immunoprecipitation. Western blotting data confirmed that Kat8-OE induced downregulation of SOD1 expression, which is a key factor for the decline of oocyte quality in advanced maternal age. Also, the injection of Myc-Sod1 cRNA could partially rescue maternal age-induced meiotic defects in oocytes. In conclusion, our data demonstrated that high level of KAT8 inhibited SOD1 activity, which in turn induced defects of mitochondrial dynamics, imbalance of redox homeostasis, and spindle/chromosome disorganization during mouse oocyte maturation.

A X-linked nonsense APOO/MIC26 variant causes a lethal mitochondrial disease with progeria-like phenotypes

APOO/MIC26 is a subunit of the MICOS complex required for mitochondrial cristae morphology and function. Here, we report a novel variant of the APOO/MIC26 gene that causes a severe mitochondrial disease with overall progeria-like phenotypes in two patients. Both patients developed partial agenesis of the corpus callosum, bilateral congenital cataract, hypothyroidism, and severe immune deficiencies. The patients died at an early age of 12 or 18 months. Exome sequencing revealed a mutation (NM_024122.5): c.532G>T (p.E178*) in the APOO/MIC26 gene that causes a nonsense mutation leading to the loss of 20 C-terminal amino acids. This mutation resulted in a highly unstable and degradation prone MIC26 protein, yet the remaining minute amounts of mutant MIC26 correctly localized to mitochondria and interacted physically with other MICOS subunits. MIC26 KO cells expressing MIC26 harboring the respective APOO/MIC26 mutation showed mitochondria with perturbed cristae architecture and fragmented morphology resembling MIC26 KO cells. We conclude that the novel mutation found in the APOO/MIC26 gene is a loss-of-function mutation impairing mitochondrial morphology and cristae morphogenesis.

Prelamin A and ZMPSTE24 in premature and physiological aging

As human longevity increases, understanding the molecular mechanisms that drive aging becomes ever more critical to promote health and prevent age-related disorders. Premature aging disorders or progeroid syndromes can provide critical insights into aspects of physiological aging. A major cause of progeroid syndromes which result from mutations in the genes LMNA and ZMPSTE24 is disruption of the final posttranslational processing step in the production of the nuclear scaffold protein lamin A. LMNA encodes the lamin A precursor, prelamin A and ZMPSTE24 encodes the prelamin A processing enzyme, the zinc metalloprotease ZMPSTE24. Progeroid syndromes resulting from mutations in these genes include the clinically related disorders Hutchinson-Gilford progeria syndrome (HGPS), mandibuloacral dysplasia-type B, and restrictive dermopathy. These diseases have features that overlap with one another and with some aspects of physiological aging, including bone defects resembling osteoporosis and atherosclerosis (the latter primarily in HGPS). The progeroid syndromes have ignited keen interest in the relationship between defective prelamin A processing and its accumulation in normal physiological aging. In this review, we examine the hypothesis that diminished processing of prelamin A by ZMPSTE24 is a driver of physiological aging. We review features a new mouse (LmnaL648R/L648R) that produces solely unprocessed prelamin A and provides an ideal model for examining the effects of its accumulation during aging. We also discuss existing data on the accumulation of prelamin A or its variants in human physiological aging, which call out for further validation and more rigorous experimental approaches to determine if prelamin A contributes to normal aging.

Hutchinson-Gilford Progeria Syndrome: Cellular Mechanisms and Therapeutic Perspectives

In humans, aging is characterized by a gradual decline of physical and psychological functions, with the concomitant onset of chronic-degenerative diseases, which ultimately lead to death. The study of Hutchinson-Gilford progeria syndrome (HGPS), a premature aging disorder that recapitulates several features of natural aging, has provided important insights into deciphering the aging process. The genetic origin of HGPS is a de novo point mutation in the LMNA gene that drives the synthesis of progerin, mutant version of lamin A. Progerin is aberrantly anchored to the nuclear envelope disrupting a plethora of molecular processes; nonetheless, how progerin exerts a cascade of deleterious alterations at the cellular and systemic levels is not fully understood. Over the past decade, the use of different cellular and animal models for HGPS has allowed the identification of the molecular mechanisms underlying HGPS, paving the way towards the development of therapeutic treatments against the disease. In this review, we present an updated overview of the biology of HGPS, including its clinical features, description of key cellular processes affected by progerin (nuclear morphology and function, nucleolar activity, mitochondrial function, protein nucleocytoplasmic trafficking and telomere homeostasis), as well as discussion of the therapeutic strategies under development.

Lonafarnib and everolimus reduce pathology in iPSC-derived tissue engineered blood vessel model of Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare, fatal genetic disease that accelerates atherosclerosis. With a limited pool of HGPS patients, clinical trials face unique challenges and require reliable preclinical testing. We previously reported a 3D tissue engineered blood vessel (TEBV) microphysiological system fabricated with iPSC-derived vascular cells from HGPS patients. HGPS TEBVs exhibit features of HGPS atherosclerosis including loss of smooth muscle cells, reduced vasoactivity, excess extracellular matrix (ECM) deposition, inflammatory marker expression, and calcification. We tested the effects of HGPS therapeutics Lonafarnib and Everolimus separately and together, currently in Phase I/II clinical trial, on HGPS TEBVs. Everolimus decreased reactive oxygen species levels, increased proliferation, reduced DNA damage in HGPS vascular cells, and improved vasoconstriction in HGPS TEBVs. Lonafarnib improved shear stress response of HGPS iPSC-derived endothelial cells (viECs) and reduced ECM deposition, inflammation, and calcification in HGPS TEBVs. Combination treatment with Lonafarnib and Everolimus produced additional benefits such as improved endothelial and smooth muscle marker expression and reduced apoptosis, as well as increased TEBV vasoconstriction and vasodilation. These results suggest that a combined trial of both drugs may provide cardiovascular benefits beyond Lonafarnib, if the Everolimus dose can be tolerated.

The role of the light source in antimicrobial photodynamic therapy

Antimicrobial photodynamic therapy (APDT) is a promising approach to fight the growing problem of antimicrobial resistance that threatens health care, food security and agriculture. APDT uses light to excite a light-activated chemical (photosensitiser), leading to the generation of reactive oxygen species (ROS). Many APDT studies confirm its efficacy in vitro and in vivo against bacteria, fungi, viruses and parasites. However, the development of the field is focused on exploring potential targets and developing new photosensitisers. The role of light, a crucial element for ROS production, has been neglected. What are the main parameters essential for effective photosensitiser activation? Does an optimal light radiant exposure exist? And finally, which light source is best? Many reports have described the promising antibacterial effects of APDT in vitro, however, its application in vivo, especially in clinical settings remains very limited. The restricted availability may partially be due to a lack of standard conditions or protocols, arising from the diversity of selected photosensitising agents (PS), variable testing conditions including light sources used for PS activation and methods of measuring anti-bacterial activity and their effectiveness in treating bacterial infections. We thus sought to systematically review and examine the evidence from existing studies on APDT associated with the light source used. We show how the reduction of pathogens depends on the light source applied, radiant exposure and irradiance of light used, and type of pathogen, and so critically appraise the current state of development of APDT and areas to be addressed in future studies. We anticipate that further standardisation of the experimental conditions will help the field advance, and suggest key optical and biological parameters that should be reported in all APDT studies. More in vivo and clinical studies are needed and are expected to be facilitated by advances in light sources, leading to APDT becoming a sustainable, alternative therapeutic option for bacterial and other microbial infections in the future.

Rescue of Mitochondrial Function in Hutchinson-Gilford Progeria Syndrome by the Pharmacological Modulation of Exportin CRM1

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder caused by the expression of progerin, a mutant variant of Lamin A. Recently, HGPS studies have gained relevance because unraveling its underlying mechanism would help to understand physiological aging. We previously reported that the CRM1-mediated nuclear protein export pathway is exacerbated in HGPS cells, provoking the mislocalization of numerous protein targets of CRM1. We showed that normalization of this mechanism by pharmacologically inhibiting CRM1 with LMB (specific CRM1 inhibitor), mitigates the senescent phenotype of HGPS cells. Since mitochondrial dysfunction is a hallmark of HGPS, in this study we analyze the effect of LMB on mitochondrial function. Remarkably, LMB treatment induced the recovery of mitochondrial function in HGPS cells, as shown by the improvement in mitochondrial morphology, mitochondrial membrane potential, and ATP levels, which consequently impeded the accumulation of ROS but not mitochondrial superoxide. We provide evidence that the beneficial effect of LMB is mechanistically based on a combinatory effect on mitochondrial biogenesis via upregulation of PGC-1α expression (master transcription cofactor of mitochondrial genes), and mitophagy through the recovery of lysosomal content. The use of exportin CRM1 inhibitors constitutes a promising strategy to treat HGPS and other diseases characterized by mitochondrial impairment.

The Nuclear Envelope in Ageing and Progeria

Development from embryo to adult, organismal homeostasis and ageing are consecutive processes that rely on several functions of the nuclear envelope (NE). The NE compartmentalises the eukaryotic cells and provides physical stability to the genetic material in the nucleus. It provides spatiotemporal regulation of gene expression by controlling nuclear import and hence access of transcription factors to target genes as well as organisation of the genome into open and closed compartments. In addition, positioning of chromatin relative to the NE is important for DNA replication and repair and thereby also for genome stability. We discuss here the relevance of the NE in two classes of age-related human diseases. Firstly, we focus on the progeria syndromes Hutchinson-Gilford (HGPS) and Nestor-Guillermo (NGPS), which are caused by mutations in the LMNA and BANF1 genes, respectively. Both genes encode ubiquitously expressed components of the nuclear lamina that underlines the nuclear membranes. HGPS and NGPS patients manifest symptoms of accelerated ageing and cells from affected individuals show similar defects as cells from healthy old donors, including signs of increased DNA damage and epigenetic alternations. Secondly, we describe how several age-related neurodegenerative diseases, such as amyotrophic lateral sclerosis and Huntington's disease, are related with defects in nucleocytoplasmic transport. A common feature of this class of diseases is the accumulation of nuclear pore proteins and other transport factors in inclusions. Importantly, genetic manipulations of the nucleocytoplasmic transport machinery can alleviate disease-related phenotypes in cell and animal models, paving the way for potential therapeutic interventions.

Mesenchymal stem cells derived from patients with premature aging syndromes display hallmarks of physiological aging

Progeroid syndromes are rare genetic diseases with most of autosomal dominant transmission, the prevalence of which is less than 1/10,000,000. These syndromes caused by mutations in the LMNA gene encoding A-type lamins belong to a group of disorders called laminopathies. Lamins are implicated in the architecture and function of the nucleus and chromatin. Patients affected with progeroid laminopathies display accelerated aging of mesenchymal stem cells (MSCs)–derived tissues associated with nuclear morphological abnormalities. To identify pathways altered in progeroid patients’ MSCs, we used induced pluripotent stem cells (hiPSCs) from patients affected with classical Hutchinson–Gilford progeria syndrome (HGPS, c.1824C>T—p.G608G), HGPS-like syndrome (HGPS-L; c.1868C>G—p.T623S) associated with farnesylated prelamin A accumulation, or atypical progeroid syndromes (APS; homozygous c.1583C> T—p.T528M; heterozygous c.1762T>C—p.C588R; compound heterozygous c.1583C>T and c.1619T>C—p.T528M and p.M540T) without progerin accumulation. By comparative analysis of the transcriptome and methylome of hiPSC-derived MSCs, we found that patient’s MSCs display specific DNA methylation patterns and modulated transcription at early stages of differentiation. We further explored selected biological processes deregulated in the presence of LMNA variants and confirmed alterations of age-related pathways during MSC differentiation. In particular, we report the presence of an altered mitochondrial pattern; an increased response to double-strand DNA damage; and telomere erosion in HGPS, HGPS-L, and APS MSCs, suggesting converging pathways, independent of progerin accumulation, but a distinct DNA methylation profile in HGPS and HGPS-L compared with APS cells.

Modelling premature cardiac aging with induced pluripotent stem cells from a hutchinson-gilford Progeria Syndrome patient

Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic disorder that causes accelerated aging and a high risk of cardiovascular complications. However, the underlying mechanisms of cardiac complications of this syndrome are not fully understood. This study modeled HGPS using cardiomyocytes (CM) derived from induced pluripotent stem cells (iPSC) derived from a patient with HGPS and characterized the biophysical, morphological, and molecular changes found in these CM compared to CM derived from a healthy donor. Electrophysiological recordings suggest that the HGPS-CM was functional and had normal electrophysiological properties. Electron tomography showed nuclear morphology alteration, and the 3D reconstruction of electron tomography images suggests structural abnormalities in HGPS-CM mitochondria, however, there was no difference in mitochondrial content as measured by Mitotracker. Immunofluorescence indicates nuclear morphological alteration and confirms the presence of Troponin T. Telomere length was measured using qRT-PCR, and no difference was found in the CM from HGPS when compared to the control. Proteomic analysis was carried out in a high-resolution system using Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). The proteomics data show distinct group separations and protein expression differences between HGPS and control-CM, highlighting changes in ribosomal, TCA cycle, and amino acid biosynthesis, among other modifications. Our findings show that iPSC-derived cardiomyocytes from a Progeria Syndrome patient have significant changes in mitochondrial morphology and protein expression, implying novel mechanisms underlying premature cardiac aging.

Lamin A/C impairments cause mitochondrial dysfunction by attenuating PGC1α and the NAMPT-NAD+ pathway

Mutations in the lamin A/C gene (LMNA) cause laminopathies such as the premature aging Hutchinson Gilford progeria syndrome (HGPS) and altered lamin A/C levels are found in diverse malignancies. The underlying lamin-associated mechanisms remain poorly understood. Here we report that lamin A/C-null mouse embryo fibroblasts (Lmna-/- MEFs) and human progerin-expressing HGPS fibroblasts both display reduced NAD+ levels, unstable mitochondrial DNA and attenuated bioenergetics. This mitochondrial dysfunction is associated with reduced chromatin recruitment (Lmna-/- MEFs) or low levels (HGPS) of PGC1α, the key transcription factor for mitochondrial homeostasis. Lmna-/- MEFs showed reduced expression of the NAD+-biosynthesis enzyme NAMPT and attenuated activity of the NAD+-dependent deacetylase SIRT1. We find high PARylation in lamin A/C-aberrant cells, further decreasing the NAD+ pool and consistent with impaired DNA base excision repair in both cell models, a condition that fuels DNA damage-induced PARylation under oxidative stress. Further, ATAC-sequencing revealed a substantially altered chromatin landscape in Lmna-/- MEFs, including aberrantly reduced accessibility at the Nampt gene promoter. Thus, we identified a new role of lamin A/C as a key modulator of mitochondrial function through impairments of PGC1α and the NAMPT-NAD+ pathway, with broader implications for the aging process.

Establishment and Characterization of hTERT Immortalized Hutchinson–Gilford Progeria Fibroblast Cell Lines

Hutchinson–Gilford progeria syndrome (HGPS) is a rare premature aging syndrome caused by a dominant mutation in the LMNA gene. Previous research has shown that the ectopic expression of the catalytic subunit of telomerase (hTERT) can elongate the telomeres of the patients’ fibroblasts. Here, we established five immortalized HGP fibroblast cell lines using retroviral infection with the catalytic subunit of hTERT. Immortalization enhanced the proliferative life span by at least 50 population doublings (PDs). The number of cells with typical senescence signs was reduced by 63 + 17%. Furthermore, the growth increase and phenotype improvement occurred with a lag phase of 50–100 days and was not dependent on the degree of telomere elongation. The initial telomeric stabilization after hTERT infection and relatively low amounts of hTERT mRNA were sufficient for the phenotype improvement but the retroviral infection procedure was associated with transient cell stress. Our data have implications for therapeutic strategies in HGP and other premature aging syndromes.

Hutchinson-Gilford Progeria Syndrome: A Literature Review

Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging condition that involves genetic mutations, resulting in debilitating phenotypic features. The present state of knowledge on the molecular pathways that contribute to the pathophysiology of HGPS and the techniques being tested in vitro and in vivo to combat progerin toxicity have been discussed here. Nuclear morphological abnormalities, dysregulated gene expression, DNA repair deficiencies, telomere shortening, and genomic instability are all caused by progerin accumulation, all of which impair cellular proliferative capability. In addition, HGPS cells and preclinical animal models have revealed new information about the disease's molecular and cellular pathways and putative mechanisms involved in normal aging. This article has discussed the understanding of the molecular pathways by which progerin expression leads to HGPS and how the advanced therapy options for HGPS patients can help us understand and treat the condition.

Impact of MnTBAP and Baricitinib Treatment on Hutchinson–Gilford Progeria Fibroblasts

Hutchinson–Gilford progeria syndrome (HGPS) is a rare premature aging disease. It is caused by a mutation in the LMNA gene, which results in a 50-amino-acid truncation of prelamin A. The resultant truncated prelamin A (progerin) lacks the cleavage site for the zinc-metallopeptidase ZMPSTE24. Progerin is permanently farnesylated, carboxymethylated, and strongly anchored to the nuclear envelope. This leads to abnormalities, such as altered nuclear shape, mitochondrial dysfunction, and inflammation. HGPS patients display symptoms of physiological aging, including atherosclerosis, alopecia, lipodystrophy, and arthritis. Currently, no cure for HGPS exists. Here we focus on a drug combination consisting of the superoxide dismutase mimetic MnTBAP and JAK1/2 inhibitor baricitinib (Bar) to restore phenotypic alterations in HGPS fibroblasts. Treating HGPS fibroblasts with the MnTBAP/Bar combination improved mitochondrial functions and sustained Bar’s positive effects on reducing progerin and pro-inflammatory factor levels. Collectively, MnTBAP/Bar combination treatment ameliorates the aberrant phenotype of HGPS fibroblasts and is a potential treatment strategy for patients with HGPS.

Reactive Species in Progeroid Syndromes and Aging-Related Processes

Significance: Reactive species have been classically considered causative of age-related degenerative processes, but the scenario appears considerably more complex and to some extent counterintuitive than originally anticipated. The impact of reactive species in precocious aging syndromes is revealing new clues to understand and perhaps challenge the resulting degenerative processes. Recent Advances: Our understanding of reactive species has considerably evolved, including their hormetic effect (beneficial at a certain level, harmful beyond this level), the occurrence of diverse hormetic peaks in different cell types and organisms, and the extended type of reactive species that are relevant in biological processes. Our understanding of the impact of reactive species has also expanded from the dichotomic damaging/signaling role to modulation of gene expression. Critical Issues: These new concepts are affecting the study of aging and diseases where aging is greatly accelerated. We discuss how notions arising from the study of the underlying mechanisms of a progeroid disease, Cockayne syndrome, represent a paradigm shift that may shed a new light in understanding the role of reactive species in age-related degenerative processes. Future Issues: Future investigations urge to explore established and emerging notions to elucidate the multiple contributions of reactive species in degenerative processes linked to pathophysiological aging and their possible amelioration. Antioxid. Redox Signal. 37, 208-228.

Uric Acid Enhances Neurogenesis in a Parkinsonian Model by Remodeling Mitochondria

Background

Adult neurogenesis is the process of generating new neurons to enter neural circuits and differentiate into functional neurons. However, it is significantly reduced in Parkinson’s disease (PD). Uric acid (UA), a natural antioxidant, has neuroprotective properties in patients with PD. This study aimed to investigate whether UA would enhance neurogenesis in PD.

Methods

We evaluated whether elevating serum UA levels in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian mouse model would restore neurogenesis in the subventricular zone (SVZ). For a cellular model, we primary cultured neural precursor cells (NPCs) from post-natal day 1 rat and evaluated whether UA treatment promoted cell proliferation against 1-methyl-4-phenylpyridinium (MPP⁺).

Results

Uric acid enhanced neurogenesis in both in vivo and in vitro parkinsonian model. UA-elevating therapy significantly increased the number of bromodeoxyuridine (BrdU)-positive cells in the SVZ of PD animals as compared to PD mice with normal UA levels. In a cellular model, UA treatment increased the expression of Ki-67. In the process of modulating neurogenesis, UA elevation up-regulated the expression of mitochondrial fusion markers.

Conclusion

In MPTP-induced parkinsonian model, UA probably enhanced neurogenesis via regulating mitochondrial dynamics, promoting fusion machinery, and inhibiting fission process.

Tunable alginate hydrogels as injectable drug delivery vehicles for optic neuropathy

Many disease pathologies, particularly in the eye, are induced by oxidative stress. In particular, injury to the optic nerve (ON), or optic neuropathy, is one of the most common causes of vision loss. Traumatic optic neuropathy (TON) occurs when the ON is damaged following blunt or penetrating trauma to either the head or eye. Currently, there is no effective treatment for TON, only management options, namely the systematic delivery of corticosteroids and surgical decompression of the optic nerve. Unfortunately, neither option alleviates the generation of reactive oxygen species (ROS) which are responsible for downstream damage to the ON. Additionally, the systemic delivery of corticosteroids can cause fatal off‐target effects in cases with brain involvement. In this study, we developed a tunable injectable hydrogel delivery system for local methylene blue (MB) delivery using an internal method of crosslinking. MB was chosen due to its ROS scavenging ability and neuroprotective properties. Our MB‐loaded polymeric scaffold demonstrated prolonged release of MB as well as in situ gel formation. Additionally, following rheological characterization, these alginate hydrogels demonstrated minimal cytotoxicity to human retinal pigment epithelial cells in vitro and exhibited injection feasibility through small‐gauge needles. Our chosen MB concentrations displayed a high degree of ROS scavenging following release from the alginate hydrogels, suggesting this approach may be successful in reducing ROS levels following ON injury, or could be applied to other ocular injuries.

Geroscience-guided repurposing of FDA-approved drugs to target aging: A proposed process and prioritization

Common chronic diseases represent the greatest driver of rising healthcare costs, as well as declining function, independence, and quality of life. Geroscience-guided approaches seek to delay the onset and progression of multiple chronic conditions by targeting fundamental biological pathways of aging. This approach is more likely to improve overall health and function in old age than treating individual diseases, by addressing aging the largest and mostly ignored risk factor for the leading causes of morbidity in older adults. Nevertheless, challenges in repurposing existing and moving newly discovered interventions from the bench to clinical care have impeded the progress of this potentially transformational paradigm shift. In this article, we propose the creation of a standardized process for evaluating FDA-approved medications for their geroscience potential. Criteria for systematically evaluating the existing literature that spans from animal models to human studies will permit the prioritization of efforts and financial investments for translating geroscience and allow immediate progress on the design of the next Targeting Aging with MEtformin (TAME)-like study involving such candidate gerotherapeutics.

Mitochondrial dysfunction in mandibular hypoplasia, deafness and progeroid features with concomitant lipodystrophy (MDPL) patients

Mandibular hypoplasia, Deafness and Progeroid features with concomitant Lipodystrophy is a rare, genetic, premature aging disease named MDPL Syndrome, due to almost always a de novo variant in POLD1 gene, encoding the DNA polymerase δ. In previous in vitro studies, we have already described several hallmarks of aging, including genetic damage, telomere shortening, cell senescence and proliferation defects. Since a clear connection has been reported between telomere shortening and mitochondria malfunction to initiate the aging process, we explored the role that mitochondrial metabolism and activity play in pathogenesis of MDPL Syndrome, an aspect that has not been addressed yet. We thus evaluated mtDNA copy number, assessing a significant decrease in mutated cells.

The expression level of genes related to mitochondrial biogenesis and activity also revealed a significant reduction, highlighting a mitochondrial dysfunction in MDPL cells. Even the expression levels of mitochondrial marker SOD2, as assessed by immunofluorescence, were reduced. The decrease in this antioxidant enzyme correlated with increased production of mitochondrial ROS in MDPL cells, compared to WT. Consistent with these data, Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) analysis revealed in MDPL cells fewer mitochondria, which also displayed morphological abnormalities. Accordingly, we detected autophagic vacuoles containing partially digested mitochondria.

Overall, our results demonstrate a dramatic impairment of mitochondrial biogenesis and activity in MDPL Syndrome. Administration of Metformin, though unable to restore mitochondrial impairment, proved efficient in rescuing nuclear abnormalities, suggesting its use to specifically ameliorate the premature aging phenotype.

The Potentials of Methylene Blue as an Anti-Aging Drug

Methylene blue (MB), as the first fully man-made medicine, has a wide range of clinical applications. Apart from its well-known applications in surgical staining, malaria, and methemoglobinemia, the anti-oxidative properties of MB recently brought new attention to this century-old drug. Mitochondrial dysfunction has been observed in systematic aging that affects many different tissues, including the brain and skin. This leads to increaseding oxidative stress and results in downstream phenotypes under age-related conditions. MB can bypass Complex I/III activity in mitochondria and diminish oxidative stress to some degree. This review summarizes the recent studies on the applications of MB in treating age-related conditions, including neurodegeneration, memory loss, skin aging, and a premature aging disease, progeria.

Preclinical Advances of Therapies for Laminopathies

Laminopathies are a group of rare disorders due to mutation in LMNA gene. Depending on the mutation, they may affect striated muscles, adipose tissues, nerves or are multisystemic with various accelerated ageing syndromes. Although the diverse pathomechanisms responsible for laminopathies are not fully understood, several therapeutic approaches have been evaluated in patient cells or animal models, ranging from gene therapies to cell and drug therapies. This review is focused on these therapies with a strong focus on striated muscle laminopathies and premature ageing syndromes.

Hutchinson-Gilford Progeria Syndrome (Hgps) And Application Of Gene Therapy Based Crispr/Cas Technology As A Promising Innovative Treatment Approach

BACKGROUND

Hutchinson-Gilford progeria syndrome (HGPS) also known as progeria of childhood or progeria is a rare, rapid, autosomal dominant genetic disorder characterized by premature aging which occurs shortly after birth. HGPS occurs as a result of de novo point mutation in the gene recognized as LMNA gene that encodes two proteins Lamin A protein and Lamin C protein which are the structural components of the nuclear envelope. Mutations in the gene trigger abnormal splicing and induce internal deletion of 50 amino acids leading to the development of a truncated form of Lamin A protein known as Progerin. Progerin generation can be considered as the crucial step in HGPS since the protein is highly toxic to human cells, permanently farnesylated, and exhibits variation in several biochemical and structural properties within the individual. HGPS also produces complications such as skin alterations, growth failure, atherosclerosis, hair and fat loss, and bone and joint diseases. We have also revised all relevant patents relating to Hutchinson-gilford progeria syndrome and its therapy in the current article.

METHOD

The goal of the present review article is to provide information about Hutchinson-Gilford progeria syndrome (HGPS) and the use of CRISPR/Cas technology as a promising treatment approach in the treatment of the disease. The review also discusses about different pharmacological and non-pharmacological methods of treatment currently used for HGPS.

RESULTS

The main limitation associated with progeria is the lack of a definitive cure. The existing treatment modality provides only symptomatic relief. Therefore, it is high time to develop a therapeutic method that hastens premature aging in such patients.

CONCLUSION

CRISPR/Cas technology is a novel gene-editing tool that allows genome editing at specific loci, and is found to be a promising therapeutic approach for the treatment of genetic disorders such as HGPS where dominant-negative mutations take place.

Small-Molecule Therapeutic Perspectives for the Treatment of Progeria

Hutchinson-Gilford progeria syndrome (HGPS), or progeria, is an extremely rare disorder that belongs to the class of laminopathies, diseases characterized by alterations in the genes that encode for the lamin proteins or for their associated interacting proteins. In particular, progeria is caused by a point mutation in the gene that codifies for the lamin A gene. This mutation ultimately leads to the biosynthesis of a mutated version of lamin A called progerin, which accumulates abnormally in the nuclear lamina. This accumulation elicits several alterations at the nuclear, cellular, and tissue levels that are phenotypically reflected in a systemic disorder with important alterations, mainly in the cardiovascular system, bones, skin, and overall growth, which results in premature death at an average age of 14.5 years. In 2020, lonafarnib became the first (and only) FDA approved drug for treating progeria. In this context, the present review focuses on the different therapeutic strategies currently under development, with special attention to the new small molecules described in recent years, which may represent the upcoming first-in-class drugs with new mechanisms of action endowed with effectiveness not only to treat but also to cure progeria.

Mechanisms of angiogenic incompetence in Hutchinson-Gilford progeria via downregulation of endothelial NOS

Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disorder with features of accelerated aging. The majority of HGPS cases are caused by a de novo point mutation in the LMNA gene (c.1824C>T; p.G608G) resulting in progerin, a toxic lamin A protein variant. Children with HGPS typically die from coronary artery diseases or strokes at an average age of 14.6 years. Endothelial dysfunction is a known driver of cardiovascular pathogenesis; however, it is currently unknown how progerin antagonizes normal angiogenic function in HGPS. Here, we use human iPSC‐derived endothelial cell (iPSC‐EC) models to study angiogenesis in HGPS. We cultured normal and HGPS iPSC‐ECs under both static and fluidic culture conditions. HGPS iPSC‐ECs show reduced endothelial nitric oxide synthase (eNOS) expression and activity compared with normal controls and concomitant decreases in intracellular nitric oxide (NO) level, which result in deficits in capillary‐like microvascular network formation. Furthermore, the expression of matrix metalloproteinase 9 (MMP‐9) was reduced in HGPS iPSC‐ECs, while the expression of tissue inhibitor metalloproteinases 1 and 2 (TIMP1 and TIMP2) was upregulated relative to healthy controls. Finally, we used an adenine base editor (ABE7.10max‐VRQR) to correct the pathogenic c.1824C>T allele in HGPS iPSC‐ECs. Remarkably, ABE7.10max‐VRQR correction of the HGPS mutation significantly reduced progerin expression to a basal level, rescued nuclear blebbing, increased intracellular NO level, normalized the misregulated TIMPs, and restored angiogenic competence in HGPS iPSC‐ECs. Together, these results provide molecular insights of endothelial dysfunction in HGPS and suggest that ABE could be a promising therapeutic approach for correcting HGPS‐related cardiovascular phenotypes.

Ultraviolet radiation protection potentials of Methylene Blue for human skin and coral reef health

Methylene blue (MB) is a century-old medicine, a laboratory dye, and recently shown as a premier antioxidant that combats ROS-induced cellular aging in human skins. Given MB's molecular structure and light absorption properties, we hypothesize that MB has the potential to be considered as a sunscreen active for UV radiation protection. In this study, we tested the effects of MB on UVB ray-induced DNA double-strand breaks in primary human keratinocytes. We found that MB treatment reduced DNA damages caused by UVB irradiation and subsequent cell death. Next, we compared MB with Oxybenzone, which is the most commonly used chemical active ingredient in sunscreens but recently proven to be hazardous to aquatic ecosystems, in particular to coral reefs. At the same concentrations, MB showed more effective UVB absorption ability than Oxybenzone and significantly outperformed Oxybenzone in the prevention of UVB-induced DNA damage and the clearance of UVA-induced cellular ROS. Furthermore, unlike Oxybenzone, MB-containing seawater did not affect the growth of the coral species Xenia umbellata. Altogether, our study suggests that MB has the potential to be a coral reef-friendly sunscreen active ingredient that can provide broad-spectrum protection against UVA and UVB.

Injectable self-healing bioactive antioxidative one-component poly(salicylic acid) hydrogel with strong ultraviolet-shielding for preventing skin light injury

The design and development of one-component temperature-sensitive bioactive hydrogel with multifunctional properties for protecting skin against light injury remain a challenge. Herein, we report a bioactive multifunctional poly(salicylic acid)-F127-poly(salicylic acid) copolymer hydrogel (FPSa) with one-component for potential skin protection applications. The FPSa hydrogel possesses the thermosensitivity (23 °C), injectability, self-healing ability, ultraviolet shielding (shielding the wavelength between 280 and 370 nm), and antioxidation activity (above 70%), and also showed the good cytocompatibility (cell survival rate >90% and hemolysis rate less than 5%) and biodegradability (90% weight loss at 3 days). The in vivo animal model showed that FPSa hydrogel could effectively protect the skin tissue and prevent the ultraviolet induced injury. This study can provide a strategy to design multifunctional bioactive hydrogel with simple composition for disease therapy and regenerative medicine.

Self-assembly of multi-component mitochondrial nucleoids via phase separation

Mitochondria contain an autonomous and spatially segregated genome. The organizational unit of their genome is the nucleoid, which consists of mitochondrial DNA (mtDNA) and associated architectural proteins. Here, we show that phase separation is the primary physical mechanism for assembly and size control of the mitochondrial nucleoid (mt-nucleoid). The major mtDNA-binding protein TFAM spontaneously phase separates in vitro via weak, multivalent interactions into droplets with slow internal dynamics. TFAM and mtDNA form heterogenous, viscoelastic structures in vitro, which recapitulate the dynamics and behavior of mt-nucleoids in vivo. Mt-nucleoids coalesce into larger droplets in response to various forms of cellular stress, as evidenced by the enlarged and transcriptionally active nucleoids in mitochondria from patients with the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS). Our results point to phase separation as an evolutionarily conserved mechanism of genome organization.

Hydroxyapatite nanocomposite as a potential agent in osteosarcoma PDT

Using Nanoplatforms as a hauler for photosensitizers is a bespoke paradigm to improve its bioavailability and to boost the PDT efficacy. Herein, the photodynamic cytotoxicity of methylene blue (MB) loaded on hydroxyapatite nanoparticles (HA-NPs) was tested against human osteosarcoma-derived cells (Saos-2 cell line). HA-NPs and HA-NPs loaded with MB (HA-NPs-MB) were prepared by a chemical precipitation method and characterized by TEM, Zeta potential, FTIR, and XRD. TEM images revealed that HA-NPs have a rod shape with a diameter of 14-17 nm and length around 46-64 nm. FTIR and Zeta potential confirmed the adsorption of cationic MB on HA-NPs. XRD pattern was identical to the standard XRD pattern of HA-NPs. Incubation of Saos-2 cells (24 h) with HA-NPs-MB then irradiation of cells (5 min) with a diode laser (808 nm), causes a higher decrement of cell viability (determined by MTT assay) than that caused by free MB. The LC₅₀ was 57.53 µg/mL and 86.99 µg/mL for HA-NPs-MB and free MB, respectively. Thus, the nanoformulation of MB greatly reduced the dose of MB required for effective PDT. This study also investigated the mode of cell death after incubation of cells with free MB or HA-NPs-MB composite then exposure to laser radiation. The results revealed that the majority of cells died by apoptosis while a minor fraction of cells died by necrosis, especially in the case of HA-NPs-MB. Levels of caspase-3 and death receptor-4 (DR-4) were more elevated in the case of HA-NPs-MB than free MB. The effect of the prepared nanocomposite and free MB on Raw murine macrophage (RAW 264.7) viability was also examined using the MTT assay. The results indicated that HA-NPs-MB in the presence of laser has a great cytotoxic effect on macrophage cells compared to other treatments. This may present an advantage through decreasing macrophage that promotes tumor growth. In conclusion, HA-NPs-MB nanocomposite surmounts free MB and HA-NPs in destroying macrophage cells and Saos-2 cells through apoptosis in the presence of laser irradiation. This study introduces a thorough and new insight on osteosarcoma (cancer cell line Saos-2) PDT using HA-NPs-MB exploiting the biosafety of HA-NPs.

Premature aging disorders: A clinical and genetic compendium

Progeroid disorders make up a heterogeneous group of very rare hereditary diseases characterized by clinical signs that often mimic physiological aging in a premature manner. Apart from Hutchinson-Gilford progeria syndrome, one of the best-investigated progeroid disorders, a wide spectrum of other premature aging phenotypes exist, which differ significantly in their clinical presentation and molecular pathogenesis. Next-generation sequencing (NGS)-based approaches have made it feasible to determine the molecular diagnosis in the early stages of a disease. Nevertheless, a broad clinical knowledge on these disorders and their associated symptoms is still fundamental for a comprehensive patient management and for the interpretation of variants of unknown significance from NGS data sets. This review provides a detailed overview on characteristic clinical features and underlying molecular genetics of well-known as well as only recently identified premature aging disorders and also highlights novel findings towards future therapeutic options.

Loss of MTX2 causes mandibuloacral dysplasia and links mitochondrial dysfunction to altered nuclear morphology

Mandibuloacral dysplasia syndromes are mainly due to recessive LMNA or ZMPSTE24 mutations, with cardinal nuclear morphological abnormalities and dysfunction. We report five homozygous null mutations in MTX2, encoding Metaxin-2 (MTX2), an outer mitochondrial membrane protein, in patients presenting with a severe laminopathy-like mandibuloacral dysplasia characterized by growth retardation, bone resorption, arterial calcification, renal glomerulosclerosis and severe hypertension. Loss of MTX2 in patients' primary fibroblasts leads to loss of Metaxin-1 (MTX1) and mitochondrial dysfunction, including network fragmentation and oxidative phosphorylation impairment. Furthermore, patients' fibroblasts are resistant to induced apoptosis, leading to increased cell senescence and mitophagy and reduced proliferation. Interestingly, secondary nuclear morphological defects are observed in both MTX2-mutant fibroblasts and mtx-2-depleted C. elegans. We thus report the identification of a severe premature aging syndrome revealing an unsuspected link between mitochondrial composition and function and nuclear morphology, establishing a pathophysiological link with premature aging laminopathies and likely explaining common clinical features.

Lamin A involvement in ageing processes

Lamin A, a main constituent of the nuclear lamina, is the major splicing product of the LMNA gene, which also encodes lamin C, lamin A delta 10 and lamin C2. Involvement of lamin A in the ageing process became clear after the discovery that a group of progeroid syndromes, currently referred to as progeroid laminopathies, are caused by mutations in LMNA gene. Progeroid laminopathies include Hutchinson-Gilford Progeria, Mandibuloacral Dysplasia, Atypical Progeria and atypical-Werner syndrome, disabling and life-threatening diseases with accelerated ageing, bone resorption, lipodystrophy, skin abnormalities and cardiovascular disorders. Defects in lamin A post-translational maturation occur in progeroid syndromes and accumulated prelamin A affects ageing-related processes, such as mTOR signaling, epigenetic modifications, stress response, inflammation, microRNA activation and mechanosignaling. In this review, we briefly describe the role of these pathways in physiological ageing and go in deep into lamin A-dependent mechanisms that accelerate the ageing process. Finally, we propose that lamin A acts as a sensor of cell intrinsic and environmental stress through transient prelamin A accumulation, which triggers stress response mechanisms. Exacerbation of lamin A sensor activity due to stably elevated prelamin A levels contributes to the onset of a permanent stress response condition, which triggers accelerated ageing.

Progress and trends in the development of therapies for Hutchinson-Gilford progeria syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is an autosomal-dominant genetic disease that leads to accelerated aging and often premature death caused by cardiovascular complications. Till now clinical management of HGPS has largely relied on the treatment of manifestations and on the prevention of secondary complications, cure for the disease has not yet been established. Addressing this need cannot only benefit progeria patients but may also provide insights into intervention design for combating physiological aging. By using the systematic review approach, this article revisits the overall progress in the development of strategies for HGPS treatment over the last ten years, from 2010 to 2019. In total, 1,906 articles have been retrieved, of which 56 studies have been included for further analysis. Based on the articles analyzed, the trends in the use of different HGPS models, along with the prevalence, efficiency, and limitations of different reported treatment strategies, have been examined. Emerging strategies for preclinical studies, and possible targets for intervention development, have also been presented as avenues for future research.

Hutchinson-Gilford progeria syndrome: Rejuvenating old drugs to fight accelerated ageing

What if the next generation of successful treatments was hidden in the current pharmacopoeia? Identifying new indications for existing drugs, also called the drug repurposing or drug rediscovery process, is a highly efficient and low-cost strategy. First reported almost a century ago, drug repurposing has emerged as a valuable therapeutic option for diseases that do not have specific treatments and rare diseases, in particular. This review focuses on Hutchinson-Gilford progeria syndrome (HGPS), a rare genetic disorder that induces accelerated and precocious aging, for which drug repurposing has led to the discovery of several potential treatments over the past decade.

Pharmacotherapy to gene editing: potential therapeutic approaches for Hutchinson-Gilford progeria syndrome

Hutchinson-Gilford progeria syndrome (HGPS), commonly called progeria, is an extremely rare disorder that affects only one child per four million births. It is characterized by accelerated aging in affected individuals leading to premature death at an average age of 14.5 years due to cardiovascular complications. The main cause of HGPS is a sporadic autosomal dominant point mutation in LMNA gene resulting in differently spliced lamin A protein known as progerin. Accumulation of progerin under nuclear lamina and activation of its downstream effectors cause perturbation in cellular morphology and physiology which leads to a systemic disorder that mainly impairs the cardiovascular system, bones, skin, and overall growth. Till now, no cure has been found for this catastrophic disorder; however, several therapeutic strategies are under development. The current review focuses on the overall progress in the field of therapeutic approaches for the management/cure of HGPS. We have also discussed the new disease models that have been developed for the study of this rare disorder. Moreover, we have highlighted the therapeutic application of extracellular vesicles derived from stem cells against aging and aging-related disorders and, therefore, suggest the same for the treatment of HGPS.

Peroxisomal abnormalities and catalase deficiency in Hutchinson-Gilford Progeria Syndrome

Peroxisomes are small, membrane-enclosed eukaryotic organelles that house various enzymes with metabolic functions. One important feature in both Hutchinson-Gilford Progeria Syndrome (HGPS) and normal aging is the elevated levels of Reactive Oxygen Species (ROS), which are generated from metabolic pathways with the capacity to cause oxidative damage to macromolecules within the cells. Although peroxisomal bioreactions can generate free radicals as their byproducts, many metabolic enzymes within the peroxisomes play critical roles as ROS scavengers, in particular, catalase. Here, we observed impaired peroxisomes-targeting protein trafficking, which suggested that the poorly assembled peroxisomes might cause high oxidative stress, contributing to the premature senescent phenotype in HGPS. We then investigated the ROS clearance efficiency by peroxisomal enzymes and found a significantly decreased expression of catalase in HGPS. Furthermore, we evaluated the effects of two promising HGPS-treatment drugs Methylene Blue and RAD001 (Everolimus, a rapamycin analog) on catalase in HGPS fibroblasts. We found that both drugs effectively reduced cellular ROS levels. MB, as a well-known antioxidant, did not affect catalase expression or activity. Interestingly, RAD001 treatment significantly upregulated catalase activity in HGPS cells. Our study presents the first characterization of peroxisomal function in HGPS and provides new insights into the cellular aspects of HGPS and the ongoing clinical trial.

iPSC-Derived Endothelial Cells Affect Vascular Function in a Tissue-Engineered Blood Vessel Model of Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a rare disorder caused by a point mutation in the Lamin A gene that produces the protein progerin. Progerin toxicity leads to accelerated aging and death from cardiovascular disease. To elucidate the effects of progerin on endothelial cells, we prepared tissue-engineered blood vessels (viTEBVs) using induced pluripotent stem cell-derived smooth muscle cells (viSMCs) and endothelial cells (viECs) from HGPS patients. HGPS viECs aligned with flow but exhibited reduced flow-responsive gene expression and altered NOS3 levels. Relative to viTEBVs with healthy cells, HGPS viTEBVs showed reduced function and exhibited markers of cardiovascular disease associated with endothelium. HGPS viTEBVs exhibited a reduction in both vasoconstriction and vasodilation. Preparing viTEBVs with HGPS viECs and healthy viSMCs only reduced vasodilation. Furthermore, HGPS viECs produced VCAM1 and E-selectin protein in TEBVs with healthy or HGPS viSMCs. In summary, the viTEBV model has identified a role of the endothelium in HGPS.

Metabolic Dysfunction in Hutchinson-Gilford Progeria Syndrome

Hutchinson–Gilford Progeria Syndrome (HGPS) is a segmental premature aging disease causing patient death by early teenage years from cardiovascular dysfunction. Although HGPS does not totally recapitulate normal aging, it does harbor many similarities to the normal aging process, with patients also developing cardiovascular disease, alopecia, bone and joint abnormalities, and adipose changes. It is unsurprising, then, that as physicians and scientists have searched for treatments for HGPS, they have targeted many pathways known to be involved in normal aging, including inflammation, DNA damage, epigenetic changes, and stem cell exhaustion. Although less studied at a mechanistic level, severe metabolic problems are observed in HGPS patients. Interestingly, new research in animal models of HGPS has demonstrated impressive lifespan improvements secondary to metabolic interventions. As such, further understanding metabolism, its contribution to HGPS, and its therapeutic potential has far-reaching ramifications for this disease still lacking a robust treatment strategy.

Identification of hub genes, key pathways, and therapeutic agents in Hutchinson-Gilford Progeria syndrome using bioinformatics analysis

BACKGROUND

Hutchinson-Gilford Progeria syndrome (HGPS) is a rare lethal premature and accelerated aging disease caused by mutations in the lamin A/C gene. Nevertheless, the mechanisms of cellular damage, senescence, and accelerated aging in HGPS are not fully understood. Therefore, we aimed to screen potential key genes, pathways, and therapeutic agents of HGPS by using bioinformatics methods in this study.

METHODS

The gene expression profile of GSE113648 and GSE41751 were retrieved from the gene expression omnibus database and analyzed to identify the differentially expressed genes (DEGs) between HGPS and normal controls. Then, gene ontology and the Kyoto encyclopedia of genes and genomes pathway enrichment analysis were carried out. To construct the protein-protein interaction (PPI) network, we used STRING and Cytoscape to make module analysis of these DEGs. Besides, the connectivity map (cMAP) tool was used as well to predict potential drugs.

RESULTS

As a result, 180 upregulated DEGs and 345 downregulated DEGs were identified, which were significantly enriched in pathways in cancer and PI3K-Akt signaling pathway. The top centrality hub genes fibroblast growth factor 2, decorin, matrix metallopeptidase2, and Fos proto-oncogene, AP-1 transcription factor subunit were screened out as the critical genes among the DEGs from the PPI network. Dexibuprofen and parthenolide were predicted to be the possible agents for the treatment of HGPS by cMAP analysis.

CONCLUSION

This study identified key genes, signal pathways and therapeutic agents, which might help us improve our understanding of the mechanisms of HGPS and identify some new therapeutic agents for HGPS.

Mitochondria-Targeting Thermosensitive Initiator with Enhanced Anticancer Efficiency

As one of the most important organelles in cells, the mitochondrion has been reported to exhibit higher temperatures and is vulnerable to free radicals, especially in cancer cells. Here, we report on the use of a mitochondria-targeted thermosensitive radical initiator for cancer cell killing. The thermal-sensitive radical initiator, V044 (2,2'-azobis [2-(2-imidazolin-2-yl)propane]dihydrochloride), was applied as a radical source, which was linked with a mitochondrial targeting moiety, triphenylphosphine (TPP), to construct the mitochondria-targeting radical initiator (TPPV). Mitochondria were applied as the endogenous thermal source of cells, which accelerated the free radical generation of TPPV. Results showed that TPPV could effectively generate free radicals in the mitochondrial area, and the released free radicals effectively damaged mitochondria, exhibiting an enhanced anticancer efficiency. This therapy based on endogenous mitochondrial heat avoids tissue penetration limits and offers a target for mitochondria-targeting systems.