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Jayaprakash, D.

Publications and source records attributed to Jayaprakash, D..

3 recordsLinked to original sources

Central platelet-rich plasma administration promotes weight loss in diet-induced obese mice

Aims: Platelet-rich plasma (PRP) contains diverse bioactive factors, but its potential role in central regulation of energy balance remains unexplored. This study investigated whether central PRP administration alters metabolic homeostasis in diet-induced obese (DIO) mice and examined associated hypothalamic responses under obese and inflammatory conditions. Materials and Methods: PRP was administered intracerebroventricularly in mouse models of DIO and lipopolysaccharide (LPS)-induced systemic inflammation. Body weight, food intake, energy metabolism, and adiposity were assessed alongside hypothalamic microglial morphology and transcriptomic profiling. Results: A single intracerebroventricular PRP injection reduced body weight in DIO mice, with the effect persisting throughout the 7-day observation period. PRP also decreased cumulative food intake, relative gonadal white adipose tissue weight, and fasting glucose, accompanied by increased energy expenditure, oxygen consumption, fat utilization, and physical activity. In both DIO and LPS-treated mice, PRP reduced IBA1-positive area per microglial cell in the arcuate nucleus without altering microglial number. Hypothalamic RNA sequencing revealed changes in immune and metabolic signaling, extracellular matrix organization, and growth-related pathways, suggesting a complex transcriptional response rather than uniform suppression of inflammation. Conclusions: A single central PRP administration induces sustained weight loss and favorable metabolic changes in DIO mice, accompanied by region-specific hypothalamic microglial and transcriptional responses. These findings identify central PRP as a potential modulator of energy balance and provide a basis for investigating its active components and underlying mechanisms.

neuroscience↗

The RING Finger E3 Ligase RNF25 Protects DNA Replication Forks Independently of its Canonical Roles in Ubiquitin Signaling

The DNA damage response (DDR) mechanisms that allow cells to tolerate DNA replication stress are critically important for genome stability and cell viability. Using an unbiased genetic screen we identify a role for the RING finger E3 ubiquitin ligase RNF25 in promoting DNA replication stress tolerance. In response to DNA replication stress, RNF25-deficient cells generate aberrantly high levels of single-stranded DNA (ssDNA), accumulate in S-phase and show reduced mitotic entry. Using single-molecule DNA fiber analysis, we show that RNF25 protects reversed DNA replication forks generated by the fork remodeler HLTF from nucleolytic degradation by MRE11 and CtIP. Mechanistically, RNF25 interacts with the replication fork protection factor REV7 and recruits REV7 to nascent DNA after replication stress. The role of RNF25 in protecting replication forks is fully separable from its canonical functions in ubiquitin conjugation. This work reveals the RNF25-REV7 signaling axis as an important protective mechanism in cells experiencing replication stress.

molecular biology↗

A Degenerate PCNA-Interacting Peptide (DPIP) box targets RNF168 to replicating DNA to limit 53BP1 signaling

The E3 ligase RNF168 has been suggested to have roles at DNA replication forks in addition to its canonical functions in DNA double-strand break (DSB) signaling. However, the precise role of RNF168 in DNA replication remains unclear. Here we demonstrate that RNF168 is recruited to DNA replication factories independent of the canonical DSB response pathway regulators and identify a degenerate PCNA-Interacting Peptide (DPIP) motif in the C-terminus of RNF168 which mediates its binding to PCNA. An RNF168 mutant harboring substitutions in the DPIP box fails to interact with PCNA and is not recruited to sites of DNA synthesis, yet fully retains its ability to promote DSB-induced 53BP1 foci. Surprisingly, the RNF168 DPIP mutant also retains the ability to support ongoing DNA replication fork movement, demonstrating that PCNA-binding is dispensable for normal S-phase functions. However, replisome-associated RNF168 functions to suppress the DSB-induced 53BP1 DNA damage response during S-phase. Moreover, we show that WT RNF168 can perform PCNA ubiquitylation independently of RAD18 and also synergizes with RAD18 to amplify PCNA ubiquitylation. Taken together, our results identify non-canonical functions of RNF168 at the replication fork and demonstrate new mechanisms of cross talk between the DNA damage and replication stress response pathways.

cancer biology↗