Biology subjects

Puviindran, V.

Publications and source records attributed to Puviindran, V..

3 recordsLinked to original sources

bioRxiv2026

Age-Dependent Effects of Macrophage Derived Cathelicidin Antimicrobial Peptide on Bone Fracture Repair

The pace of fracture repair declines with age, increasing the risk of delayed union and nonunion. Delayed union and nonunion are associated with significant morbidity and even mortality with few effective non-surgical interventions. Here, we identify cathelicidin antimicrobial peptide (CAMP) as an age-dependent regulator of bone repair. Single-cell RNA sequencing and immunohistochemistry demonstrated higher CAMP expression during fracture healing in young compared with aged mice. Global or myeloid lineage-depletion of Camp delayed fracture repair in young mice, whereas Camp depletion in aged mice increased callus bone formation. Heterochronic bone marrow transplantation using the conditional genetic knockout further implicated hematopoietic-lineage derived cells in these effects and demonstrated that myeloid-specific Camp expression is important in the rejuvenation of the pace of fracture healing. CAMP promotes osteogenic differentiation through P2X7 receptor (P2X7R)-dependent signaling, influencing the downstream regulation of NLRP3 expression. NLRP3 expression is also correlated with osteogenesis following Camp modulation in both young and old mice, supporting CAMP-P2X7R-NLRP3 signaling as a regulator of osteogenesis. Together, these findings identify CAMP as a hematopoietic-derived regulator of bone repair whose function is age-dependent, promoting fracture healing in young animals while constraining it in aged animals.

cell biology↗

bioRxiv2026

Muscle-to-Bone CX3CL1 Signaling Promotes Skeletal Repair Through CX3CR1+ Osteoprogenitors

In the context of muscle loss, bone repair is impaired, suggesting that muscle derived signals contribute to bone regeneration. However, how muscle surrounding the injury site communicates with the bone repair niche remains unclear. Here we found that CX3CL1 expression was induced in endothelial cells in muscle surrounding a femoral bone injury site. Deletion of Cx3cl1 impaired bone healing, demonstrating a functional role for CX3CL1 in bone repair. A CX3CL1 receptor, CX3CR1, was expressed by PDGFR stromal progenitors and lineage tracing showed that CX3CR1 expressing osteoprogenitor lineage cells accumulated at the injury site during repair. PDGFR stromal progenitors showed enhanced osteoblastogenesis in response to recombinant CX3CL1. In older mice, local CX3CL1 delivery increased PDGFRCX3CR1 osteoprogenitor accumulation and improved bone repair. These findings identify a muscle bone signaling pathway in which endothelial CX3CL1 promotes bone repair through CX3CR1 expressing osteoprogenitors.

cell biology↗

bioRxiv2021

Distinct roles of glutamine metabolism in benign and malignant cartilage tumors with IDH mutations

Enchondromas and chondrosarcomas are common cartilage neoplasms that are either benign or malignant respectively. The majority of these tumors harbor mutations in either IDH1 or IDH2. Glutamine metabolism has been implicated as a critical regulator of tumors with IDH mutations. Chondrocytes and chondrosarcomas with mutations in the IDH1 or IDH2 genes showed enhanced glutamine utilization in downstream metabolism. Using genetic and pharmacological approaches, we demonstrated that glutaminase-mediated glutamine metabolism played distinct roles in enchondromas and chondrosarcomas with IDH1 or IDH2 mutations. Deletion of glutaminase in chondrocytes with Idh1 mutation increased the number and size of enchondroma-like lesions. Pharmacological inhibition of glutaminase in chondrosarcoma xenografts reduced overall tumor burden. Glutamine affected cell differentiation and viability in these tumors differently through different downstream metabolites. During murine enchondroma-like lesion development, glutamine-derived -ketoglutarate promoted hypertrophic chondrocyte differentiation and regulated chondrocyte proliferation. In human chondrosarcoma, glutamine-derived non-essential amino acids played an important role in preventing cell apoptosis. This study reveals that glutamine metabolism can play distinct roles in benign and malignant cartilage tumors sharing the same genetic mutations. Inhibiting GLS may provide a therapeutic approach to suppress chondrosarcoma tumor growth.

cancer biology↗