Progeria Research Articles

Hutchinson - Gilford syndrome (Progeria): Clinical and Postmortem Findings

Hutchinson-Gilford Progeria syndrome, a rare genetic syndrome is being reviewed in this communication. It has striking features resembling premature aging. In most patients, Hutchinson-Gilford Progeria syndrome is caused by new genetic changes that occur randomly for unknown reasons. These changes (mutations) are transmitted as an autosomal dominant trait. Involving aberrant splicing of the LMNAgene, resulting in the production of a disease-causing mutant lamin Aprotein called progerin. Because neither parent carries or expresses the mutation, each case is believed to represent a sporadic, new mutation that happens most notably in a single sperm or egg immediately prior to conception. Children with progeria usually have a normal appearance in early infancy. At approximately six months of age, there are profound growth delays, resulting in low weight, premature bodily aging (progeria) and dwarfism. They have a birdlike, “wizened old man” facial appearance. These individuals die because of atherosclerosis and myocardial infarction. In this review article, we have reviewed several studies and reports regarding the genetic basis, diagnoses with characteristics and development of Hutchinson - Gilford syndrome (HGPS) or progéria. This review summarizes the clinical characteristics of this disease, the underlying mutation in the lamin A (LMNA) gene that results in this phenotype and PM findings through articles found in the databases: PubMed Central, Scielo, BVS, Bireme, Scientific Electronic Library Online etc.

Progerin and Its Role in Accelerated and Natural Aging

Well-known theories of aging suggest that a certain metabolic defect negatively affects vital activity of the cell, be it oxidative stress, the accumulation of lesions in DNA, the exhaustion of telomeres, or distorted epigenetic processes. The theory of aging considered in the review postulates that an accumulation of progerin on the inner side of the nuclear envelope underlies the above defects. Progerin is a defective precursor of the lamin A nuclear matrix protein in which the C-terminal cysteine, which is removed normally, is retained and modified with a hydrophobic oligoisoprene chain. Progerin molecules attach with their hydrophobic processes to the inner membrane of the nuclear envelope, pushing away the adjacent fibrils of the nuclear matrix and the chromatin periphery. This changes the morphology and shape of the nucleus and alters the properties of the nuclear envelope and pore complexes embedded in it. As progerin accumulates in the nucleus, structural distortions increase in the nucleus, further distorting the nuclear-cytoplasmic transport of macromolecules and leading to the above defects in cell metabolism. This leads to increasing cell death and aging of the body over time. This mechanism of aging has been identified in patients with Hutchinson-Gilford progeria syndrome (HGPS). Mass progerin production in HGPS is caused by the point mutation c.1824C→T in exon 11 of the LMNA gene, which codes for lamins A and C. The mutation stimulates non-standard splicing of the primary transcript during the formation of the lamin A precursor mRNA, thus causing progerin production. Children with progeria who have received the mutation from one of their parents age rapidly and die before 15 years of age. Approaches to progeria treatment are aimed at preventing the formation of progerin or destroying the progerin that has already accumulated. In the latter case, a promising strategy is to use rapamycin or its analogs and other substances and techniques that activate autophagy to purify the cell from progerin. Although in much smaller amounts, progerin is found in progeria-free people and may therefore play a role in natural aging. A maximum age that a person can reach is possible to estimate by taking account of the role that progerin plays in telomere shortening. Encouraging preliminary results achieved in purifying cells from progerin provide a means to develop an optimal procedure for periodic purification of the human body from progerin in order to reduce the rate of aging.

Monitoring of Chromatin Organization at the Nuclear Pore Complex, Inner Nuclear Membrane, and Nuclear Interior in Live Cells by Fluorescence Ratiometric Imaging of Chromatin (FRIC).

The image analysis tool FRIC (Fluorescence Ratiometric Imaging of Chromatin) quantitatively monitors dynamic spatiotemporal distribution of euchromatin and total chromatin in live cells. A vector (pTandemH) assures stoichiometrically constant expression of the histone variants Histone 3.3 and Histone 2B, fused to EGFP and mCherry, respectively. Quantitative ratiometric (H3.3/H2B) imaging displayed a concentrated distribution of heterochromatin in the periphery of U2OS cell nuclei. As a proof of concept, peripheral heterochromatin responded to experimental manipulation of histone acetylation as well as expression of the mutant lamin A protein "progerin," which causes Hutchinson-Gilford Progeria Syndrome. In summary FRIC is versatile, unbiased, robust, requires a minimum of experimental steps and is suitable for screening purposes.

Neurovascular disease: 2022 update.

In this update we present a series of papers focused on topics that have emerged in vascular disease over the prior year. The first two papers focus on the pathogenesis of vascular malformations, the first on brain arteriovenous malformations, and the second on cerebral cavernous malformations. These disorders can lead to significant brain injuries from intracerebral hemorrhage (if they rupture) or other neurological complications, including seizures. The next set of papers reflects work that has advanced our understanding of how the brain and the immune system "communicate" after brain injury, including stroke (papers 3-6). The first of these shows that T cells are involved in white matter repair after ischemic injury, an effect dependent on microglia, demonstrating the important cross-talk between innate and adaptive immunity. The next two papers focus on B cells, which have been relatively understudied in the context of brain injury. The contribution of antigen-experienced B cells from the meninges and skull bone marrow, rather than blood-derived B cells in neuroinflammation opens up a very novel area of investigation. The possibility that antibody secreting B cells may contribute to vascular dementia will certainly be an active area for future investigations. Similarly, in paper 6, investigators found that CNS-infiltrating myeloid cells can originate from brain borders tissues. These cells have unique transcriptional signatures that are distinct from their blood-derived counterparts, and likely contribute to myeloid cell infiltration from bone-marrow niches in close proximity to the brain. The contribution of microglia, the primary innate immune cell of the brain, to amyloid deposition and propagation is then discussed, followed by work on how perivascular Aβ is potentially cleared along the cerebral vessels in patients with cerebral amyloid angiopathy. The final two papers focus on the contribution of senescent endothelial cells and pericytes. The first used a model of accelerated senescence (Hutchinson-Gilford progeria syndrome; HGPS) and shows the translational potential of an approach to reduce telomere shortening to slow aging. The final paper demonstrates how capillary pericytes contribute to basal blood flow resistance and slow modulation of blood flow throughout the brain. Interestingly, several of the papers identified therapeutic strategies that could be potentially translated into clinical populations.

Hutchinson-Gilford Syndrome (Progeria) with Heterozygous Mutation in the LMNA Gene-ENST00000368300.9 Presenting with Mandibuloacral Dysplasia and Acrogeroid Features-Overlap of Premature Aging Syndromes.

Hutchinson-Gilford Syndrome (Progeria) with Heterozygous Mutation in the LMNA Gene-ENST00000368300.9 Presenting with Mandibuloacral Dysplasia and Acrogeroid Features-Overlap of Premature Aging Syndromes.

Genetic basis of cardiovascular aging is at the core of human longevity

Aging is an archetypical complex process influenced by genetic and environmental factors. Genetic variants impart a gradient of effect sizes, albeit the effect sizes seem to be skewed toward those with small effect sizes. On one end of the spectrum are the rare monogenic premature aging syndromes, such as Hutchinson Gilford Progeria Syndrome, whereby single nucleotide changes lead to rapidly progressive premature aging. On the end of the spectrum is the complex, slowly progressive process of living to an arbitrary-defined old age, i.e., longevity. Whereas the genetic basis of rare premature aging syndromes has been elucidated, only a small fraction of the genetic determinants of longevity and life span, time from birth to death, have been identified. The latter point to the complexity of the process and involvement of myriad of genetic and non-genetic factors and hence, the diluted effect of each determinant on longevity. The genetic discoveries point to the involvement of the DNA damage and activation of the DNA damage response pathway, particularly in the premature aging syndromes. Likewise, the insulin/insulin-like growth factor 1/mTOR/FOXO pathways have emerged as major regulators of life span. A notable fraction of the genetic variants that are associated with life span is also associated with age-related cardiovascular diseases, such as coronary artery disease and dyslipidemia, which places cardiovascular aging at the core of human life span. The clinical impact of the discoveries pertains to the identification of the pathways that are involved in life span, which might serve as targets of interventions to prevent, slow, and even possibly reverse aging.

Hutchinson-Gilford Progeria Syndrome (Hgps) and Application of Gene Therapy Based Crispr/Cas Technology as A Promising Innovative Treatment Approach

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 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. 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. 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. 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.

LMNA-mediated nucleoskeleton dysregulation in Alzheimer disease.

Nucleoskeleton dysfunction has been implicated in Alzheimer disease (AD). Tubular invaginations of the nuclear envelope observed in AD brains are consistent with the accumulation of farnesylated prelamin A (encoded by the LMNA gene) that occurs in Hutchinson-Gilford Progeria Syndrome, a premature aging disorder caused by LMNA mutations. Proper function of the nuclear membrane is required for neuronal survival and for maintenance of genetic architecture. To determine whether dysregulated LMNA expression and prelamin A processing are responsible for nucleoskeleton dysfunction in AD, we performed differential gene expression and network analyses in human AD and age-matched control brains. Lamin A protein levels were evaluated in AD and control brains using mass spectrometry. Gene network analyses were carried out using induced pluripotent stem cell-derived neurons transduced with progerin or GFP controls in order to identify molecular pathways influenced by altered LMNA processing. In AD brains, we observed a significant increase in LMNA and a significant decrease in ZMPSTE24, resulting in a significant increase Lamin A protein levels, which we observe through mass spectrometry. We replicated these findings in laser capture microdissected neurons from AD brains, suggesting that the effect is neuronally driven. Thus, high levels of LMNA paired with low levels of ZMPSTE24 could result in the accumulation of farnesylated prelamin A and tubular invaginations in the nuclear membrane. LMNA-associated networks were also differentially expressed in AD brains. Genes within the dysregulated LMNA network were enriched in lysosomal and chromatin remodeling pathways. Our findings suggest that β-amyloid and tau accumulation disrupts prelamin A processing and downstream changes in the nuclear membrane. Alterations in the nucleoskeleton induce genomic instability, loss of proteostasis, and cellular senescence, which may accelerate AD pathogenesis.

C10. An ultra-rare case of Hutchinson–Gilford progeria syndrome with severe aortic regurgitation due to bicuspid aortic valve in a 9-year-old girl

Abstract Background Hutchinson-Gilford progeria syndrome (HGPS) is an ultra-rare autosomal dominant that result in progressive premature aging syndrome. Cardiovascular diseases become the main cause of mortality including myocardial infarction, interstitial myocardial fibrosis, hypertension and calcification of the mitral and aortic valves. However, the relationship between HGPS and bicuspid aortic valve (BAV) has not been documented yet. Case Summary A 9-year-old girl with HGPS presented to the outpatient clinic with a complaint of shortness of breath since 5 years ago, especially when she did moderate physical activity. Chest pain and palpitation were denied. Her physical examination revealed short stature, thin, wrinkled skin, craniofacial disproportion with alopecia, shrunken facies and prominent scalp veins. There was failure to thrive and diastolic murmur grade 2/4 is heard on the aortic area. Laboratory test showed leukocytosis. Transthoracic echocardiogram showed severe aortic regurgitation due to calcified bicuspid aortic valve and mild mitral regurgitation. She was managed by conservative therapy because her parents were still considering the aortic valve repair procedure. Discussion The HGPS patient with severe aortic regurgitation due to BAV should be managed to reduce cardiovascular complications. Aortic valve repair is an interesting alternative to replacement managing aortic regurgitation due to BAV in young adults. Recently, advanced science about BAV disease and refinement of surgical techniques improved standardization of BAV repair procedure.

C10. An ultra-rare case of Hutchinson–Gilford progeria syndrome with severe aortic regurgitation due to bicuspid aortic valve in a 9-year-old girl

Abstract Background Hutchinson-Gilford progeria syndrome (HGPS) is an ultra-rare autosomal dominant that result in progressive premature aging syndrome. Cardiovascular diseases become the main cause of mortality including myocardial infarction, interstitial myocardial fibrosis, hypertension and calcification of the mitral and aortic valves. However, the relationship between HGPS and bicuspid aortic valve (BAV) has not been documented yet. Case Summary A 9-year-old girl with HGPS presented to the outpatient clinic with a complaint of shortness of breath since 5 years ago, especially when she did moderate physical activity. Chest pain and palpitation were denied. Her physical examination revealed short stature, thin, wrinkled skin, craniofacial disproportion with alopecia, shrunken facies and prominent scalp veins. There was failure to thrive and diastolic murmur grade 2/4 is heard on the aortic area. Laboratory test showed leukocytosis. Transthoracic echocardiogram showed severe aortic regurgitation due to calcified bicuspid aortic valve and mild mitral regurgitation. She was managed by conservative therapy because her parents were still considering the aortic valve repair procedure. Discussion The HGPS patient with severe aortic regurgitation due to BAV should be managed to reduce cardiovascular complications. Aortic valve repair is an interesting alternative to replacement managing aortic regurgitation due to BAV in young adults. Recently, advanced science about BAV disease and refinement of surgical techniques improved standardization of BAV repair procedure.

Abstract 12533: Progerin Causes a Disproportionate Senescence in Endothelial Cells

Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disorder caused by the mutation of LMNA gene leading to irreversibly farnesylated lamin A protein, i.e. progerin. The major causes of death in HGPS are coronary and arterial occlusive disease. In the murine model of HGPS, vascular smooth muscle cells (VSMCs) loss is the primary vascular manifestation, which is quite different from the human arterial occlusive disease. To identify the mechanisms of HGPS vascular disease in humans, we differentiated isogenomic endothelial cells (ECs) and VSMCs from the same lines of HGPS-iPSCs and control-iPSCs. Both HGPS-ECs and HGPS-VSMCs manifested cellular hallmarks of aging, including dysmorphic nuclei, impaired proliferation, increased β-galactosidase staining, shortened telomeres, upregulated secretion of inflammatory cytokines, increased DNA damage, loss of heterochromatin and altered shelterin complex expression. However, at similar passage number, HGPS-ECs are more severely affected compared to VSMCs, as indicated by a higher percentage of β-galactosidase positive cells, significantly shortened telomere length, and greater frequency of DNA damage signals. With increasing passage number, there is progressive senescence in HGPS-ECs that is greater than that observed in HGPS-VSMCs. Using immunoprecipitation and mass spectrometry, we compared the integrity of the Shelterin Protein Complex (SPC), which is composed of six different proteins and whose function is to protect the telomeres, on the ECs and VSMCs of HGPS and control cells. We observed increased γH2A.X binding to RAP1 (member of SPC) and to Lamin A (nuclear envelope) in HGPS cells. The expression of γH2A.X was greater in HGPS ECs than VSMCs, and is associated with loss of SPC integrity, telomere shortening and loss of heterochromatin formation. Whereas progerin expression has deleterious effect in both vascular ECs and VSMCs, the severity of dysfunction is more extensive in HGPS-ECs in comparison to HGPS-VSMCs. These studies indicate that an endothelial-targeted therapy may be useful in HGPS.

Abstract 11821: Telomerase Therapy Reverses Vascular Senescence and Extends Lifespan in Progeria Mice

Background: Hutchinson-Gilford Progeria Syndrome (HGPS) is an accelerated aging syndrome associated with premature vascular disease and death due to heart attack and stroke. In HGPS a mutation in lamin A (progerin), alters nuclear morphology and gene expression. Current therapy increases the lifespan of these children only modestly. Thus, greater understanding of the underlying mechanisms of HGPS is required to improve therapy. Endothelial cells (ECs) differentiated from induced pluripotent stem cells (iPSCs) derived from these patients exhibit hallmarks of senescence including replication arrest, DNA damage, increased expression of inflammatory markers and telomere erosion. We hypothesized that correction of shortened telomeres may reverse these measures of vascular aging. Methods: We generated ECs from iPSCs belong to children with HGPS and their unaffected parents. Telomerase mRNA (hTERT) was used to treat HGPS ECs. Endothelial morphology and functions were assessed, as well as proteomic and transcriptional profiles with attention to inflammatory markers, DNA damage and EC identity genes. In a mouse model of HGPS, we assessed the effects of lentiviral transfection of mTERT on measures of senescence, focusing on the EC phenotype in various organs. Results: hTERT treatment of human HGPS ECs improved replicative capacity; restored endothelial functions such as nitric oxide generation, acLDL uptake and angiogenesis; and reduced the elaboration of inflammatory cytokines. In addition, hTERT treatment improved cellular and nuclear morphology, in association with a normalization of the transcriptional profile, effects which may be mediated in part by a reduction in progerin expression and an increase in SIRT1. Progeria mice treated with mTERT Lentivirus manifested similar improvements, with a reduction in inflammatory and DNA damage markers and increased SIRT1 in their vasculature and other organs. Furthermore, mTERT therapy increased the lifespan of HGPS mice. Conclusion: Vascular rejuvenation using telomerase mRNA is a promising approach for progeria and other age-related diseases.

Abstract 10732: Systemic Administration of Telomerase RNA Reverses Vascular Senescence and Extends Lifespan in Progeria Mice

Introduction: Hutchinson-Gilford Progeria Syndrome (HGPS) is an accelerated aging syndrome associated with premature vascular disease and death due to heart attack and stroke. In HGPS, a mutation in lamin A (progerin) alters nuclear morphology and gene expression. iPSCs derived endothelium from progeria patients show impairment in their morphology and function including replication arrest, DNA damage, increased expression of inflammatory markers, and telomere erosion, compared to iPSCs derived endothelial cells from their unaffected parents. We have shown that hTERT mRNA therapy rescues their senescent phenotypes and restores normal function and gene expression in-vitro. To validate our finding in-vivo, we have used lentivirus harboring mouse telomerase to treat mice model of progeria and investigated the beneficial effects on mice vasculature in different organs. Hypothesis: Gene therapy with mRNA encoding mice telomerase improves survival and reversing cell senescence in a mice model of HGPS. Methods: HGPS mice were injected twice with a lentivirus construct encoding mice telomerase via tail vein. Mice were monitored for survival; endothelial cells were isolated at the time of euthanasia and concentrations of cytokines, chemokines, and growth factors were analyzed using Elisa, PCR and immunofluorescence staining. For clinical translation we developed a lipid nanoparticle formulation to deliver mRNA encoding mTERT to mice, validating its function using mRNA encoding Luciferase to demonstrate biodistribution and safety profile. Results: Two treatments with lentiviral mTERT increased the lifespan of HGPS mice by 20% and reduced mediators of inflammation and thrombosis in HGPS such as thrombomodulin. HGPS mice treated with mTERT had lower DNA damage markers and increased SIRT1 in their vasculature and other organs. A Lipid nanoparticle encapsulating mTERT RNA and shows a favorable safety profile and the capacity to systemically and safely deliver luciferase mRNA, generating active luciferase, documenting a predominantly hepatic biodistribution. Conclusions: Vascular rejuvenation using telomerase mRNA is a promising approach for progeria and other age-related diseases. Further development in systemic delivery is thus underway

Abstract 11757: Telomerase Treatment Restores Transcriptional Profile and Epigenetic Landscape in Progeria Vascular Cells

Hutchinson-Gilford progeria syndrome (HGPS) is a model of accelerated vascular aging caused by a de novo mutation of a single nucleotide in the Lamin A gene. The accumulation of abnormal lamin A (progerin) in the nuclear envelope induces a nuclear dysmorphology associated with global gene dysregulation, increased expression of inflammatory cytokines, impaired vascular function, and accelerated telomere erosion. These individuals succumb to myocardial infarction or stroke in their mid-teens. We hypothesized that restoration of telomere length might reverse some of the observed derangements in cell function, transcriptional profile and epigenetic alterations. Accordingly, we generated iPSC-derived endothelial cells (ECs) from HGPS children and their unaffected parents. By comparison to the parental controls, HGPS ECs have severely impaired replicative capacity, cellular functions (e.g. NO synthesis, acLDL uptake, network formation, cytokine secretion) and severe telomere shortening. We observed that transient transfection with mRNA encoding human telomerase (hTERT) increases telomere length, restores cellular replicative capacity and improves HGPS-EC functions. Notably, RNAseq studies revealed that that approximately 1200 genes were dysregulated in Progeria, most of which were improved by hTERT treatment, among which approximately 250+ genes were fully normalized. Intriguingly, hTERT treatment reduces DNA damage signals (γH2Ax) and reverses the aberrant chromatin accessibility observed in HGPS-ECs, as assessed by a reduction in the activating histone mark H3K4me3; an increase in the suppressive mark H3K4me3; and normalizes the level of heterochromatin markers HP1, Histone H1 and H3. Preliminary results from ChIPseq studies targeting histone marks characteristic of activators, repressors and enhancers as well as chromatin remodeling proteins; together with Hi-C analyses indicate that there are global changes in topologically associated domains (TADs) and other features of the chromatin landscape in HGPS ECs, which are partially restored by hTERT treatment. We conclude that hTERT treatment has surprisingly global effects on transcriptional profile and epigenetic landscape in addition to telomere extension.

Abstract 10730: Vascular Smooth Muscle Cell Phenotypic Switch and Replication Stress as a Key Contributors in CVD in HGPS

Hutchinson Gilford Progeria Syndrome is a premature aging disease caused by LMNA gene mutation and production of a truncated lamin A protein “progerin” that elicits cellular and organismal toxicity. Patients show severe aging phenotypes, including alopecia, reduced fat and bone density, and cardiovascular disease (CVD), which ultimately causes their death as teenagers. HGPS has no cure and clinical trials obtained only minor benefits. It is urgent to identify mechanisms of progerin toxicity to target therapeutically. Progerin accumulates preferentially in the vasculature, being especially toxic for vascular smooth muscle cells (VSMC). Patients' autopsies show that vessel stiffening and aortic atherosclerosis are accompanied by VSMCs depletion in the media, increased extracellular matrix (ECM), and adventitia thickening. Mechanisms whereby progerin causes massive VSMC loss and ECM accumulation are unknown. We previously demonstrated that progerin expression in fibroblasts hinders DNA replication, causes genomic instability, and triggers a phenotypic switch towards activated fibroblasts/myofibroblasts. These cells are known to promote tissue fibrosis by ECM deposition and release of inflammatory cytokines. VSMCs can also undergo phenotypic modulation or de-differentiation, a process whereby contractile cells revert to a synthetic/proliferative phenotype, leading to pathological accumulation of ECM and CVD. Here we show that progerin expression in VSMCs causes a switch towards the synthetic/proliferative phenotype. Similarly to fibroblasts, progerin represents a challenge for DNA replication in VSMC, triggering replication stress, genomic instability and ultimately VSMC death. Importantly, we found that calcitriol -hormonal active form of vitamin D- prevents VSMC switch and replication stress. Our data suggest that replication stress might be an underlying cause of VSMC loss in progeria and that preventing the phenotypic switch-induced replication stress with compounds such as calcitriol might prevent the massive loss of VSMC and the vascular stiffness in HGPS patients.

Ocular manifestations in a case of progeroid syndrome

Progeria syndromes are very rare genetic diseases characterized by premature aging changes. There are several phenotypes and variables noted in literature in some cases difficult to specifically classify a specific syndrome. It occurs due to mutation in DNA repair genes. The most common ocular findings are loss of eyebrow and eyelashes, brow ptosis, lid margin changes, entropion, Meibomian gland dysfunction, severe dry eye, corneal opacity, cataract, poor mydriasis, and rod-cone dystrophy. We report this case with all the above ocular manifestations in 19year old teenager with additional finding being retinal detachment.

Toward CRISPR Therapies for Cardiomyopathies.

Toward CRISPR Therapies for Cardiomyopathies.

The Impact of Rare Human Variants on Barrier-To-Auto-Integration Factor 1 (Banf1) Structure and Function.

Barrier-to-Autointegration Factor 1 (Banf1/BAF) is a critical component of the nuclear envelope and is involved in the maintenance of chromatin structure and genome stability. Banf1 is a small DNA binding protein that is conserved amongst multicellular eukaryotes. Banf1 functions as a dimer, and binds non-specifically to the phosphate backbone of DNA, compacting the DNA in a looping process. The loss of Banf1 results in loss of nuclear envelope integrity and aberrant chromatin organisation. Significantly, mutations in Banf1 are associated with the severe premature ageing syndrome, Néstor–Guillermo Progeria Syndrome. Previously, rare human variants of Banf1 have been identified, however the impact of these variants on Banf1 function has not been explored. Here, using in silico modelling, biophysical and cell-based approaches, we investigate the effect of rare human variants on Banf1 structure and function. We show that these variants do not significantly alter the secondary structure of Banf1, but several single amino acid variants in the N- and C-terminus of Banf1 impact upon the DNA binding ability of Banf1, without altering Banf1 localisation or nuclear integrity. The functional characterisation of these variants provides further insight into Banf1 structure and function and may aid future studies examining the potential impact of Banf1 function on nuclear structure and human health.

Age-Acquired Downregulation of Lmna Leads to Epigenetic Deregulation and Altered HSPC Function

Hematopoietic stem cells (HSCs) exhibit epigenetic reprogramming and decline in function with aging, and these changes may be predisposing mechanisms for development of clonal hematopoiesis and myeloid malignancies. Our recent study characterizing the epigenetic and transcriptional landscape of young (18-30 years) and aged (65-75 years) human CD34 +CD38 - bone marrow (BM) cells identified Lamin-A/C (LMNA) as one of the most downregulated genes with aging (7.9-fold, p=1.9x10 -13). LMNA encodes the nuclear lamina protein Lamin-A/C and is mutated in the premature aging disorder Hutchinson-Gilford Progeria Syndrome.To determine whether downregulation of LMNA contributes to the phenotype of human HSC aging, we knocked down LMNA (LMNA KD) using shRNA in young, mobilized peripheral blood CD34 + cells. With an average knockdown of 60%, we observed ~33% increase in myeloid colony forming potential (p<0.05). LMNA KD also impaired differentiation in liquid culture as determined by persistence of CD34 expression in twice as many cells as controls (p<0.0001) while induction of myeloid CD11b expression was reduced by ~29% (p<0.05), as well as a trend to reduced erythroid (CD71 +GYPA +) differentiation. To investigate the effects of Lmna loss-of-function in vivo, we conditionally deleted Lmna in mice using Vav-Cre. Loss of Lmna (Lmna KO) had no effect on steady state hematopoiesis in young (10 weeks) or middle-aged (14 months) knockout mice. However, Lmna KO BM cells from middle-aged mice generated 2-fold more total colonies than wild-type, floxed controls (WT=126 vs KO=292, p<0.01).Given that nuclear architecture provides a layer of epigenetic regulation through chromatin-lamina interactions, we investigated how the epigenome changes in the context of LMNA deficiency. By super-resolution microscopy, we observed loss of LMNA localization from the nuclear periphery in LMNA KD human CD34 +cells (p<0.05). Since lamina-associated domains generally contain regions of repressed chromatin, we stained for histone H3K9me2 and observed that LMNA KD cells displayed increased scattering throughout the nucleus without a change in its density. Next, we performed ATAC-seq and identified 603 open chromatin sites showing changes in accessibility (FDR<0.1). Over 73% of these sites show reduced accessibility and were associated with genes showing reduced expression by RNA-seq. Gene ontology analysis of these sites identified genes associated with heme biosynthetic and cell differentiation processes (FDR<0.005). Moreover, gene set enrichment analysis of the RNA-seq confirmed that downregulated genes were enriched for genes downregulated in our previously reported CD34 + aging signature (NES=-1.46, FDR=0.001). To determine whether LMNA KD alters the epigenome, we performed ChIP-seq for active (H3K4me3, H3K27ac) and repressive (H3K9me2) histone marks. LMNA KD resulted in significant reduction of 36% of H3K27ac peaks, which mimics our previous observation of marked age-related losses of H3K27ac. Most differential peaks localized to gene promoters (50%) and introns (34%) and include genes involved in nuclear pore organization and gene silencing (FDR<0.001). Notably, for peaks located at intergenic regions, >35% overlapped with active enhancers we reported as lost with aging and were associated with genes involved in regulation of p38 MAPK cascade (enrichment=2.34E -5), an important signaling pathway regulating proliferation and differentiation of HSCs and leukemic cells.Taken together, LMNA deficiency recapitulates features of aging at the functional and epigenetic level. LMNA KD in young, human CD34 + cells impaired their differentiation while increasing their colony forming potential. Similarly in middle-aged mice, LMNA KO BM cells showed increased colony forming potential. Genomic changes induced by LMNA deficiency include reduced accessibility and gene transcription, accompanied by changes in localization and occupancy of histone H3K9me2 and H3K27ac, respectively. These epigenetic changes affect genes regulating differentiation and signaling pathways. Thus, we have demonstrated that in addition to its structural role, LMNA also contributes to chromatin regulation of hematopoietic pathways important for normal CD34 + function. DisclosuresNo relevant conflicts of interest to declare.

New pharmaceuticals approved by FDA in 2020: Small-molecule drugs derived from amino acids and related compounds.

Amino acids (AAs) play an important role in the modern health industry as key synthetic precursors for pharmaceuticals, biomaterials, biosensors, and drug delivery systems. Currently, over 30% of small-molecule drugs contain residues of tailor-made AAs or derived from them amino-alcohols and di-amines. In this review article, we profile 12 AA-derived new pharmaceuticals approved by the FDA in 2020. These newly introduced drugs include Tazverik (epithelioid sarcoma), Gemtesa (overactive bladder), Zeposia (multiple sclerosis), Byfavo (induction and maintenance of procedural sedation), Cu 64 dotatate, and Gallium 68 PSMA-11 (both PET imaging), Rimegepant (acute migraine), Zepzelca (lung cancer), Remdesivir (COVID-19), Amisulpride (nausea and vomiting), Setmelanotide (obesity), and Lonafarnib (progeria syndrome). For each compound, we describe the spectrum of biological activity, medicinal chemistry discovery, and synthetic preparation.