Retnlg, encoding resistin-like molecule (RELM)-γ, is associated with immune-related functions [2]. It may play roles in pathways related to immune cell regulation and inflammation, and is of biological importance in understanding immune-mediated processes [1,2,3,4,5,6,7,8,9]. Genetic models such as KO/CKO mouse models can be valuable for further exploring its functions.

In skin wound healing, the expression of Retnlg was associated with migrating neutrophils in a study on the impact of human umbilical cord mesenchymal stem cell-derived exosomes [1]. In the context of mesenchymal stem/stromal cell-induced myeloid-derived suppressor cells (MDSCs), these MSC-induced MDSCs highly expressed Retnlg, though RELM-γ encoded by Retnlg had no direct effects on T cell proliferation, Treg expansion, or splenocyte activation [2].

In acute inflammatory lung injury, differential expression of Retnlg was seen in mice with acute lung injury caused by pulmonary and extrapulmonary factors [3]. In bladder cancer, a subpopulation of RETNLG+LCN2+ senescence-like neutrophils preferentially accumulated in the male tumor microenvironment, exerting an immunosuppressive effect [4].

In gastric pre-neoplastic and neoplastic development, Retnlg was among the genes highly enriched in gastric CD11b+Ly6G+ granulocytic MDSCs following Helicobacter felis infection [5]. In atopic dermatitis in mice, topical emollient treatment downregulated genes in the lung involved in leucocyte chemotaxis, including Retnlg [6].

In Clonorchis sinensis -infected mouse livers, Retnlg was up-regulated at both the gene and protein levels, associated with liver fibrosis and inflammation [7]. In preeclampsia, pro-inflammatory macrophages at the maternal-fetal interface inhibited the production of Ly6g+S100a8+S100a9+Retnlg+Wfdc21+ gMDSCs, leading to PE-like symptoms in mice [8]. In ulcerative colitis, Retnlg was identified as a biomarker for assessing BPA-induced colitis [9].

In conclusion, Retnlg is mainly involved in immune-related biological functions, including immune cell regulation, inflammation, and chemotaxis. Studies using mouse models have revealed its roles in various disease areas such as skin wound healing, bladder cancer, gastric diseases, atopic dermatitis, liver fibrosis, and preeclampsia, providing insights into disease mechanisms and potential biomarker discovery.