Eva-Maria Lederer

Background/Objectives: Hutchinson–Gilford progeria syndrome (HGPS) is a rare and fatal genetic disease caused by a silent mutation in the LMNA gene, leading to the production of progerin, a defective prelamin A variant. Progerin accumulation disrupts nuclear integrity, alters chromatin organization, and drives systemic cellular dysfunction. While autophagy and inflammation are key dysregulated pathways in HGPS, the role of microRNAs (miRNAs) in these processes remains poorly understood. Methods: We performed an extensive literature review to identify miRNAs involved in autophagy and inflammation. Through stem-loop RT-qPCR in aging HGPS and control fibroblast strains, we identified significant miRNAs and focused on the most prominent one, miR-181a-5p, for in-depth analysis. We validated our in vitro findings with miRNA expression studies in skin biopsies from an HGPS mouse model and conducted functional assays in human fibroblasts, including immunofluorescence staining, β-Galactosidase assay, qPCR, and Western blot analysis. Transfection studies were performed using an miR-181a-5p mimic and its inhibitor. Results: We identified miR-181a-5p as a critical regulator of premature senescence in HGPS. miR-181a-5p was significantly upregulated in HGPS fibroblasts and an HGPS mouse model, correlating with Sirtuin 1 (SIRT1) suppression and induction of senescence. Additionally, we demonstrated that TGFβ1 induced miR-181a-5p expression, linking inflammation to miRNA-mediated senescence. Inhibiting miR-181a-5p restored SIRT1 levels, increased proliferation, and alleviated senescence in HGPS fibroblasts, supporting its functional relevance in disease progression. Conclusions: These findings highlight the important role of miR-181a-5p in premature aging and suggest its potential as a therapeutic target for modulating senescence in progeroid syndromes.

Hutchinson–Gilford progeria syndrome (HGPS) is a rare, fatal, and premature aging disorder caused by progerin, a truncated form of lamin A that disrupts nuclear architecture, induces systemic inflammation, and accelerates senescence. While the farnesyltransferase inhibitor lonafarnib extends the lifespan by limiting progerin farnesylation, it does not address the chronic inflammation or the senescence-associated secretory phenotype (SASP), which worsens disease progression. In this study, we investigated the combined effects of baricitinib (BAR), a JAK1/2 inhibitor, and lonafarnib (FTI) in a Lmna^G609G/G609G mouse model of HGPS. BAR + FTI therapy synergistically extended the lifespan by 25%, surpassing the effects of either monotherapy. Treated mice showed improved health, as evidenced by reduced kyphosis, better fur quality, decreased incidence of cataracts, and less severe dysgnathia. Histological analyses indicated reduced fibrosis in the dermal, hepatic, and muscular tissues, restored cellularity and thickness in the aortic media, and improved muscle fiber integrity. Mechanistically, BAR decreased the SASP and inflammatory markers (e.g., IL-6 and PAI-1), complementing the progerin-targeting effects of FTI. This preclinical study demonstrates the synergistic potential of BAR + FTI therapy in addressing HGPS systemic and tissue-specific pathologies, offering a promising strategy for enhancing both lifespan and health.

Hutchinson–Gilford Progeria Syndrome (HGPS) is an extremely rare genetic disorder that causes accelerated aging, due to a pathogenic variant in the LMNA gene. This pathogenic results in the production of progerin, a defective protein that disrupts the nuclear lamina’s structure. In our study, we conducted a histopathological analysis of various organs in the Lmna^G609G/G609G mouse model, which is commonly used to study HGPS. The objective of this study was to show that progerin accumulation drives systemic but organ-specific tissue damage and accelerated aging phenotypes. Our findings show significant fibrosis, inflammation, and dysfunction in multiple organ systems, including the skin, cardiovascular system, muscles, lungs, liver, kidneys, spleen, thymus, and heart. Specifically, we observed severe vascular fibrosis, reduced muscle regeneration, lung tissue remodeling, depletion of fat in the liver, and disruptions in immune structures. These results underscore the systemic nature of the disease and suggest that chronic inflammation and fibrosis play crucial roles in the accelerated aging seen in HGPS. Additionally, our study highlights that each organ responds differently to the toxic effects of progerin, indicating that there are distinct mechanisms of tissue-specific damage.

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

Despite their fundamental role in assessing (patho)physiological cell states, conventional gene reporters can follow gene expression but leave scars on the proteins or substantially alter the mature messenger RNA. Multi-time-point measurements of non-coding RNAs are currently impossible without modifying their nucleotide sequence, which can alter their native function, half-life and localization. Thus, we developed the intron-encoded scarless programmable extranuclear cistronic transcript (INSPECT) as a minimally invasive transcriptional reporter embedded within an intron of a gene of interest. Post-transcriptional excision of INSPECT results in the mature endogenous RNA without sequence alterations and an additional engineered transcript that leaves the nucleus by hijacking the nuclear export machinery for subsequent translation into a reporter or effector protein. We showcase its use in monitoring interleukin-2 (IL2) after T cell activation and tracking the transcriptional dynamics of the long non-coding RNA (lncRNA) NEAT1 during CRISPR interference-mediated perturbation. INSPECT is a method for monitoring gene transcription without altering the mature lncRNA or messenger RNA of the target of interest.

Expression of exon-specific isoforms from alternatively spliced mRNA is a fundamental mechanism that substantially expands the proteome of a cell. However, conventional methods to assess alternative splicing are either consumptive and work-intensive or do not quantify isoform expression longitudinally at the protein level. Here, we therefore developed an exon-specific isoform expression reporter system (EXSISERS), which non-invasively reports the translation of exon-containing isoforms of endogenous genes by scarlessly excising reporter proteins from the nascent polypeptide chain through highly efficient, intein-mediated protein splicing. We applied EXSISERS to quantify the inclusion of the disease-associated exon 10 in microtubule-associated protein tau (MAPT) in patient-derived induced pluripotent stem cells and screened Cas13-based RNA-targeting effectors for isoform specificity. We also coupled cell survival to the inclusion of exon 18b of FOXP1, which is involved in maintaining pluripotency of embryonic stem cells, and confirmed that MBNL1 is a dominant factor for exon 18b exclusion. EXSISERS enables non-disruptive and multimodal monitoring of exon-specific isoform expression with high sensitivity and cellular resolution, and empowers high-throughput screening of exon-specific therapeutic interventions.