PTX3, or pentraxin 3, is a soluble pattern recognition molecule belonging to the humoral innate immune system [2]. It is rapidly produced at inflammatory sites by phagocytes and stromal cells in response to infection or tissue injury. PTX3 interacts with microbial moieties, pathogens, components of the complement and hemostatic systems, and extracellular matrix components. It is involved in multiple biological processes such as innate immune response, neovascularization, energy metabolism, invasion, and metastasis [1]. Gene knockout (KO) mouse models have been valuable in studying its functions.

In the context of diseases, PTX3-deficient mice showed worsening of idiopathic pulmonary fibrosis (IPF), with impaired fibrin removal and increased collagen deposition, suggesting PTX3 has a protective role in IPF [2]. In bone-related studies, Ptx3-targeted mice had reduced trabecular volume during bone development and impaired callus mineralization after experimental fracture, indicating its role in bone homeostasis [3]. In the lymphatic system, Ptx3-deficient mice had lymphatic vessel (LV) abnormalities in the colon submucosa and diaphragm, along with defective fluid drainage and dendritic cell trafficking, showing PTX3 is essential for LV structural organization and immunological function [4].

In conclusion, PTX3 is crucial for innate immunity, tissue repair, and homeostasis. Studies using KO mouse models have revealed its significance in diseases like IPF, bone-related conditions, and lymphatic system-associated functions. Understanding PTX3 can provide insights into disease mechanisms and potential therapeutic strategies for these conditions.

References:

1. Li, Duo, Hao, Zhaozhao, Nan, Yandong, Chen, Yanwei. 2023. Role of long pentraxin PTX3 in cancer. In Clinical and experimental medicine, 23, 4401-4411. doi:10.1007/s10238-023-01137-7. https://pubmed.ncbi.nlm.nih.gov/37438568/

2. Doni, Andrea, Mantovani, Alberto, Bottazzi, Barbara, Russo, Remo Castro. 2021. PTX3 Regulation of Inflammation, Hemostatic Response, Tissue Repair, and Resolution of Fibrosis Favors a Role in Limiting Idiopathic Pulmonary Fibrosis. In Frontiers in immunology, 12, 676702. doi:10.3389/fimmu.2021.676702. https://pubmed.ncbi.nlm.nih.gov/34276664/

3. Parente, Raffaella, Sobacchi, Cristina, Bottazzi, Barbara, Grčevic, Danka, Inforzato, Antonio. 2019. The Long Pentraxin PTX3 in Bone Homeostasis and Pathology. In Frontiers in immunology, 10, 2628. doi:10.3389/fimmu.2019.02628. https://pubmed.ncbi.nlm.nih.gov/31787987/

4. Doni, Andrea, Sironi, Marina, Del Prete, Annalisa, Bottazzi, Barbara, Mantovani, Alberto. 2024. PTX3 is expressed in terminal lymphatics and shapes their organization and function. In Frontiers in immunology, 15, 1426869. doi:10.3389/fimmu.2024.1426869. https://pubmed.ncbi.nlm.nih.gov/39640269/