Biology subjects

Lakenberg, N.

Publications and source records attributed to Lakenberg, N..

4 recordsLinked to original sources

bioRxiv2025

Rare longevity-associated variants, including a reduced-function mutation in cGAS, identified in multigenerational long-lived families

Life expectancy has steadily increased in the last two centuries, while healthspan has been lagging behind. Survival into extreme ages strongly clusters within families which often exhibit a delayed onset of (multi)morbidity, yet the underlying protective genetic mechanisms are still largely undefined. We performed affected sib-pair linkage analysis in 212 sibships enriched for ancestral longevity and identified four genomic regions (LODmax [≥]3.0) at 1q21.1, 6p24.3, 6q14.3, and 19p13.3. Within these regions, we prioritized 12 rare protein-altering variants in seven candidate genes (NUP210L, SLC27A3, CD1A, CGAS, IBTK, RARS2, and SH2D3A) located in longevity-associated loci. Notably, a missense variant in CGAS (rs200818241), was present in two sibships. Using human- and mouse-based cell models, we showed that rs200818241 reduced protein stability and attenuated activation of the canonical cGAS-STING pathway in a cell-type specific manner. This dampened signalling mitigated inflammation and delayed cellular senescence, mechanisms that may contribute to the survival advantage of CGAS variant carriers. Our findings indicate novel rare variants and candidate genes linked to familial longevity and highlight the cGAS-STING pathway as a potential contributor to the protective mechanisms underlying human longevity.

genetics↗

bioRxiv2023

Functional characterisation of rare variants in genes encoding the MAPK/ERK signalling pathway identified in long-lived Leiden Longevity Study participants

Human longevity, which is coupled to a compression of age-related disease, has been shown to be heritable. However, the number of identified common genetic variants linked to this trait remains small. This may indicate that longevity is, at least to some extent, determined by rare genetic variants that are potentially family-specific. We therefore investigated whole-genome sequencing data of long-lived families from the Leiden Longevity Study for family-specific variants. We identified variants residing in genes involved in the mitogen-activated protein kinase (MAPK) cascade, a lifespan-associated and evolutionarily conserved pathway emerging from studies in model organisms. We subsequently generated mouse embryonic stem cells (mESCs) harbouring these variants and conducted in vitro functional characterisation. Two variants, located in NF1 (Phe1112Leu) and RAF1 (Asp633Tyr), reduce MAPK/extracellular signal-regulated kinase (ERK) signalling pathway activity in mESCs. At the proteomic and transcriptomic level, we observed prominent changes that were shared (e.g. up-regulation of the ribosome) and opposing between the variants (e.g. down-regulation of mTORC1 signalling in the RAF1Asp633Tyr variant cell line versus up-regulation in the NF1Phe1112Leu variant cell lines). These metabolic changes were accompanied by an opposing effect of the variants on proliferation. Moreover, the RAF1Asp633Tyr variant improved resistance to replication stress, while this was not the case for the NF1Phe1112Leu variant. In conclusion, we identified two rare genetic variants in long-lived families that influence MAPK/ERK signalling in a manner that has previously been linked to increased lifespan in model organisms. Interestingly, we also observe some opposing and diverging effects between the variants, which indicates that they may either have some pleiotropic effects that are not relevant to longevity or that they target slightly different mechanisms to elicit their effects in mESCs. Our findings suggest that mESCs offer a good starting point for in vitro characterisation of rare genetic variants linked to human longevity and can be used to assess which of these variants to take forward to in vivo studies in model organisms.

genetics↗

bioRxiv2020

Elucidating another level of epigenetic regulation in osteoarthritis by identifying functional cis-acting long non-coding RNAs and their targets in articular cartilage

ObjectiveTo identify robustly differentially expressed long non-coding RNAs (lncRNAs) with osteoarthritis (OA) pathophysiology in cartilage. Moreover to explore potential target mRNAs by establishing co-expression networks, followed by functional validation. MethodsRNA sequencing was performed on macroscopically lesioned and preserved OA cartilage of patients who underwent a joint replacement surgery due to OA (N=98). Differential expression (DE) analysis was performed on lncRNAs that were annotated in GENCODE and Ensembl. To identify potential interactions, correlations were calculated between the identified DE lncRNAs and previously reported DE protein-coding genes in the same samples. Modulation of chondrocyte lncRNA expression was achieved using LNA GapmeRs. ResultsBy applying our in-house pipeline we identified 5,053 lncRNAs to be robustly expressed, of which 191 were FDR significant differentially expressed between lesioned and preserved OA cartilage. Upon integrating mRNA sequencing data, we showed that intergenic and antisense DE lncRNAs show high, positive correlations with their flanking, respectively, sense genes. To functionally validate this observation we selected P3H2-AS1, which was downregulated in primary chondrocytes, resulting in downregulation of P3H2 gene expression levels. As such, we can confirm that P3H2-AS1 regulates its sense gene P3H2. ConclusionBy applying an improved detection strategy, robustly differentially expressed lncRNAs in OA cartilage were detected. Integration of these lncRNAs with differential mRNA expression levels in the same samples showed insight into their regulatory networks. Our data signifies that intergenic, as well as antisense lncRNAs play an important role in regulating the pathophysiology of OA.

genomics↗

bioRxiv2020

RNA sequencing reveals interacting key determinants of osteoarthritis acting in subchondral bone and articular cartilage.

ObjectiveThe aim of this study was to identify key determinants of the interactive osteoarthritis (OA) pathophysiological processes of subchondral bone and cartilage. MethodsWe performed RNA sequencing on macroscopically preserved and lesioned OA subchondral bone of patients that underwent joint replacement surgery due to OA (N=24 pairs; 6 hips, 18 knees, RAAK-study). Unsupervised hierarchical clustering and differential expression analyses were performed. Results were combined with previously identified, differentially expressed genes in cartilage (partly overlapping samples) as well as with recently identified OA risk genes. ResultsWe identified 1569 genes significantly differentially expressed between lesioned and preserved subchondral bone, including CNTNAP2 (FC=2.4, FDR=3.36x10-5) and STMN2 (FC=9.6, FDR=3.36x10-3). Among the identified genes, 305 were also differentially expressed and with same direction of effects in cartilage, including IL11 and CHADL, recently acknowledged OA susceptibility genes. Upon differential expression analysis stratifying for joint site, we identified 509 genes exclusively differentially expressed in subchondral bone of the knee, such as KLF11 and WNT4. These exclusive knee genes were enriched for involvement in epigenetic processes, characterized by for instance HIST1H3J and HIST1H3H. ConclusionTo our knowledge, we are the first to report on differential gene expression patterns of paired OA subchondral bone tissue using RNA sequencing. Among the most consistently differentially expressed genes with OA pathophysiology in both bone and cartilage were IL11 and CHADL. As these genes were recently also identified as robust OA risk genes they classify as attractive druggable targets acting on two OA disease relevant tissues.

genomics↗