Biology subjects

Ziegman, R.

Publications and source records attributed to Ziegman, R..

3 recordsLinked to original sources

bioRxiv2026

ApolipoproteinE drives inflammation resolution pathways essential for recovery from Japanese encephalitis

Effective control of viral encephalitis requires immune responses that clear infection without causing damaging neuroinflammation, yet the mechanisms governing resolution and recovery remain unclear. Using a Japanese encephalitis virus mouse model spanning asymptomatic, symptomatic, and lethal trajectories, together with single-cell spatial transcriptomics and RNA-seq, we identify apolipoprotein E (ApoE) as a driver of neuroinflammation resolution. Apoe was upregulated in microglia and infiltrating myeloid cells of symptomatic survivors, where Apoe-Trem2-Tyrobp signalling promoted a phagocytic, anti-inflammatory program. In contrast, immune cells in lethal disease failed to induce Apoe and remained pro-inflammatory. ApoE-deficient mice were unable to recover following encephalitis onset, demonstrating that ApoE signalling is essential for resolution and recovery. Analysis of cerebrospinal fluid from acute encephalitis patients linked APOE isoforms to neuroinflammation resolution, with APOE{varepsilon}2 carriers exhibiting reduced neutrophils and shorter hospitalisation. These findings identify ApoE as a critical driver of neuroinflammation resolution and a promising therapeutic target for viral encephalitis.

microbiology↗

bioRxiv2024

Prenylation controls proliferation in human pluripotent stem cell-derived cardiomyocytes

Induction of cardiomyocyte proliferation to replace damaged heart tissue is a promising therapeutic approach. A recent drug screen revealed that cardiomyocytes require the mevalonate pathway for proliferation, although the specific mechanisms are unknown. In this study, we use human pluripotent stem cell-derived cardiomyocytes and cardiac organoids to further interrogate the role of the mevalonate pathway in cardiomyocyte proliferation. Chemical and genetic perturbations of the mevalonate pathway indicated that the post-translational modification, prenylation, regulates cardiomyocyte proliferation. We use prenyl probes and mass spectrometry to identify a catalogue of 40 prenylated proteins in human cardiac cells, including proteins where prenylated function had not yet been investigated. We show that multiple prenylated proteins control cardiomyocyte proliferation including RRAS2 and NAP1L4. We demonstrate that prenylation has differential effects on distinct proteins, with RRAS2 prenylation controlling membrane localization and NAP1L4 prenylation regulating cardiomyocyte mitosis and centrosome homeostasis. Together, these data show that protein prenylation is required for cardiomyocyte proliferation through multiple targets and these processes may need to be re-activated for cardiac regeneration.

cell biology↗

bioRxiv2023

CRISPR-Cas13d screens identify KILR a breast cancer risk-associated lncRNA that regulates DNA replication and repair.

Long noncoding RNAs (lncRNAs) have surpassed the number of protein-coding genes, yet the majority have no known function. We previously discovered >800 lncRNAs at regions identified by breast cancer genome-wide association studies (GWAS). Here, we performed a pooled CRISPR-Cas13d RNA knockdown screen to identify which of these lncRNAs altered cell proliferation. We found that KILR, a lncRNA that functions as a tumor suppressor, safeguards breast cells against uncontrolled proliferation. The half-life of KILR is significantly reduced by the risk haplotype, revealing an alternative mechanism by which variants alter cancer risk. We showed that KILR sequesters RPA1, a subunit of the RPA complex, required for DNA replication and repair. Reduced KILR expression promotes cell proliferation by increasing the available pool of RPA1 and the speed of DNA replication. Our findings confirm lncRNAs as mediators of breast cancer risk, emphasize the need to annotate noncoding transcripts in relevant cell types when investigating GWAS variants and provide a scalable platform for mapping phenotypes associated with lncRNAs.

cancer biology↗