We report a histiocytic sarcoma originating from the epididymis observed in a 110-week-old male CD-1 mouse in a carcinogenicity study. At necropsy, no lesions were observed in the epididymis. Histologically, a neoplastic lesion was observed in the cauda of the epididymis that was well demarcated from the surrounding tissues. The lesion mainly consisted of spindle-shaped tumor cells with oval to elongated nuclei and abundant eosinophilic or foamy cytoplasm. The tumor cells were arranged in a fascicular pattern, interlacing bundles, or a whorl pattern. The nuclei showed mild atypia with irregular shapes and varied sizes, whereas few mitotic figures and no typical multinucleated cells were observed. The epididymal ducts remained within the neoplastic lesion, and the tumor cells invaded between the epithelium and the smooth muscle layer of the epididymal duct. Immunohistochemically, the tumor cells were positive for vimentin and macrophage markers (Iba1, CD204, F4/80, and Mac-2) but negative for cytokeratin and other mesenchymal cell (α-smooth muscle actin, desmin, CD31, and platelet-derived growth factor receptor-β), neural cell (S-100 and nestin), or Leydig cell markers (calretinin). Proliferating cell nuclear antigen-positive tumor cells were sporadically observed in the lesion. Based on these results, the tumor was diagnosed as a histiocytic sarcoma originating from the epididymis. This report provides additional histopathological evidence of spontaneous histiocytic sarcomas originating from the epididymis of aged mice.

BACKGROUND: High palmitic acid (PA) levels trigger metainflammation, facilitating the onset and progression of chronic metabolic diseases. Recently, exosomes were identified as new inflammation mediators. However, the mechanism by which macrophage exosomes mediate PA-induced inflammation remains unclear.
OBJECTIVE: To explore how PA induces metainflammation through macrophage exosomes.
METHODS: Exosomes secreted by RAW264.7 mouse macrophages stimulated with PA (ExosPA) or not (Exos) were prepared by ultracentrifugation. The differential miRNAs between ExosPA and Exos were identified by high-throughput sequencing, and their targeted mRNAs and proteins were bioinformatically analyzed and verified by qPCR and western blot. Mouse macrophages and metabolic cells (AML-12 hepatocytes, C2C12 myocytes or 3T3-L1 adipocytes) were treated with ExosPA or Exos. The verified miRNAs and its targeted molecules related to inflammation were analyzed in recipient cells. Furthers, exosomes were prepared from primary peritoneal macrophages isolated from AIN93G diet-fed (Control PM-Exos) or HPD-fed (PA PM-Exos) mice. Control or PA PM-Exos were then tail vein injected (30 μg) into mice (n = 10), once a week for 2 weeks. The verified miRNA and its targets in blood, blood exosomes, and metabolic tissues were detected. Finally, measured the levels of miRNA, inflammatory factors, and fatty acids in the blood of 20 obese/overweight individuals and 20 healthy individuals.
RESULTS: ExoPA activate NF-κB signaling and enhance inflammatory enzyme/cytokine production in macrophages and metabolic cells. ExoPA enrich miR-3064-5p and target to inhibit IκBα as verified by exosome inhibitors and miR-3064-5p mimics and inhibitors. HPD elevates exosomal miR-3064-5p, macrophage exosomal miR-3064-5p, and inflammatory cytokine levels in mice circulation. PA PM-Exos from HPD-fed mice triggered inflammation in the circulation and metabolic tissues/organs of chow diet-fed mice. Overweight/obese individuals exhibit increased levels of circulating palmitoleic acid, exosomal miR-3064-5p, and high-sensitivity C-reactive proteins.
CONCLUSIONS: Macrophage exosomes transferring miR-3064-5p to target IκBα and activate NF-κB signaling in metabolic cells is a mechanism of PA-induced metainflammation.

Atherosclerosis is a chronic inflammatory vascular disease characterized by lipid metabolism disorder and lipid accumulation. Equisetin (EQST) is a hemiterpene compound isolated from fungus of marine sponge origin, which has antibacterial, anti-inflammatory, lipid-lowering, and weight loss effects. Whether EQST has anti-atherosclerotic activity has not been reported. In this study, we revealed that EQST displayed anti- atherosclerosis effects through inhibiting macrophage inflammatory response, lipid uptake and foam cell formation in vitro, and finally ameliorated high-fat diet (HFD)-induced atherosclerosis in AopE-/- mice in vivo. Mechanistically, EQST directly bound to STAT3 with high-affinity by forming hydrophobic bonds at GLN247 and GLN326 residues, as well as hydrogen bonds at ARG325 and THR346 residues. EQST interacted with STAT3 physically, and functionally inhibited the transcription activity of STAT3, thereby regulating atherosclerosis. Therefore, these results supports EQST as a candidate for developing anti-atherosclerosis therapeutic agent.

Type 2 diabetes (T2D) is on a notable rise worldwide, which leads to unfavorable outcomes during implant treatments. Surface modification of implants and exosome treatment have been utilized to enhance osseointegration. However, there has been insufficient approach to improve adverse osseointegration in T2D conditions. In this study, we successfully loaded TNF-α-treated mesenchymal stem cell (MSC)-derived exosomes onto micro/nano-network titanium (Ti) surfaces. TNF-α-licensed exosome-integrated titanium (TNF-exo-Ti) effectively enhanced M2 macrophage polarization in hyperglycemic conditions, with increased secretion of anti-inflammatory cytokines and decreased secretion of pro-inflammatory cytokines. In addition, TNF-exo-Ti pretreated macrophage further enhanced angiogenesis and osteogenesis of endothelial cells and bone marrow MSCs. More importantly, TNF-exo-Ti markedly promoted osseointegration in T2D mice. Mechanistically, TNF-exo-Ti activated macrophage autophagy to promote M2 polarization through inhibition of the PI3K/AKT/mTOR pathway, which could be abolished by PI3K agonist. Thus, this study established TNF-α-licensed exosome-immobilized titanium surfaces that could rectify macrophage immune states and accelerate osseointegration in T2D conditions.

Renal ischemia-reperfusion injury (IRI) is an integral process in renal transplantation, which results in compromised graft survival. Macrophages play an important role in both the early inflammatory period and late fibrotic period in response to IRI. In this study, we investigated whether scutellarin (SCU) could protect against renal IRI by regulating macrophage polarization. Mice were given SCU (5-50 mg/kg) by gavage 1 h earlier, followed by a unilateral renal IRI. Renal function and pathological injury were assessed 24 h after reperfusion. The results showed that administration of 50 mg/kg SCU significantly improved renal function and renal pathology in IRI mice. In addition, SCU alleviated IRI-induced apoptosis. Meanwhile, it reduced macrophage infiltration and inhibited pro-inflammatory macrophage polarization. Moreover, in RAW 264.7 cells and primary bone marrow-derived macrophages (BMDMs) exposed to SCU, we found that 150 μM SCU inhibited these cells to polarize to an inflammatory phenotype induced by lipopolysaccharide (LPS) and interferon-γ (IFN-γ). However, SCU has no influence on anti-inflammatory macrophage polarization in vivo and in vitro induced by in interleukin-4 (IL-4). Finally, we explored the effect of SCU on the activation of the mitogen-activated protein kinase (MAPK) pathway both in vivo and in vitro. We found that SCU suppressed the activation of the MAPK pathway, including the extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK), and p38. Our results demonstrated that SCU protects the kidney against IRI by inhibiting macrophage infiltration and polarization toward pro-inflammatory phenotype via the MAPK pathway, suggesting that SCU may be therapeutically important in treatment of IRI.

We investigated the phenotypic characteristics of human leukocyte antigen (HLA)-E-expressing macrophages, NKG2A/CD94 expression in T and natural killer (NK) cells, and their interactions in patients with adult-onset Still\'s disease (AOSD). Peripheral blood mononuclear cells from 22 patients with AOSD and 22 healthy controls (HC) were used. Isolated monocytes were cultured first with macrophage colony-stimulating factor to differentiate into M0 macrophages and subsequently with lipopolysaccharide/interferon-γ or interleukin-4 to differentiate into M1 or M2 macrophages, respectively. HLA-E and NKG2A/CD94 expression levels were evaluated using quantitative RT-PCR and flow cytometry. HLA-E expression in M0 and M2 macrophages was significantly higher in patients with AOSD than in HC, and was positively correlated with serum C-reactive protein levels and erythrocyte sedimentation rate. NKG2A/CD94 expression in CD4 + and CD8 + T cells was significantly higher in patients with AOSD than in HC, but that in NK cells was not significantly different. In patients with AOSD, NKG2A expression in CD4 + T cells positively correlated with HLA-E expression in M0, M1, and M2 macrophages. CD94 expression in CD8 + T cells inversely correlated with HLA-E expression in M1 and M2 macrophages. NKG2A and CD94 expression in NK cells inversely correlated with HLA-E expression in M0, M1, and M2 macrophages. No significant correlation was observed between HLA-E and NKG2A/CD94 expression in HC. Increased expression of HLA-E in macrophages and NKG2A/CD94 in T cells can be observed in the inflammatory condition of AOSD. HLA-E-expressing macrophages may be associated with NKG2A/CD94 expression in T and NK cells with different correlations.

Fuzheng Huayu recipe (FZHYR) is a Chinese patent medicine for the treatment of fibrosis. The effects of FZHYR on pulmonary fibrosis and macrophage polarization were investigated in vitro. FZHYR inhibited pulmonary inflammation and fibrosis and M2 polarization of macrophages in bleomycin-induced pulmonary fibrosis (BPF) of rat model. Differentially expressed genes were screened by high-throughput mRNA sequencing and GSEA showed that oxidative phosphorylation (OXPHOS) was correlated with BPF. FZHYR inhibited expressions of Ndufa2 and Ndufa6 in lung tissues of BPF rats. These findings suggest that OXPHOS pathway serves as a possible target for pulmonary fibrosis therapy by FZHYR.

UNASSIGNED: Sepsis is a life-threatening organ dysfunction and lack of effective measures in the current. Exosomes from mesenchymal stem cells (MSCs) reported to alleviate inflammation during sepsis, and the preconditioning of MSCs could enhance their paracrine potential. Therefore, this study investigated whether exosomes secreted by lipopolysaccharide (LPS)-pretreated MSCs exert superior antiseptic effects, and explored the underlying molecular mechanisms.
UNASSIGNED: Exosomes were isolated and characterized from the supernatants of MSCs. The therapeutic efficacy of normal exosomes (Exo) and LPS-pretreated exosomes (LPS-Exo) were evaluated in terms of survival rates, inflammatory response, and organ damage in an LPS-induced sepsis model. Macrophages were stimulated with LPS and treated with Exo or LPS-Exo to confirm the results of the in vivo studies, and to explain the potential mechanisms.
UNASSIGNED: LPS-Exo were shown to inhibit aberrant pro-inflammatory cytokines, prevent organ damages, and improve survival rates of the septic mice to a greater extent than Exo. In vitro, LPS-Exo significantly promoted the M2 polarization of macrophages exposed to inflammation. miRNA sequencing and qRT-PCR analysis identified the remarkable expression of miR-150-5p in LPS-Exo compared to that in Exo, and exosomal miR-150-5p was transferred into recipient macrophages and mediated macrophage polarization. Further investigation demonstrated that miR-150-5p targets Irs1 in recipient macrophages and subsequently modulates macrophage plasticity by down-regulating the PI3K/Akt/mTOR pathway.
UNASSIGNED: The current findings highly suggest that exosomes derived from LPS pre-conditioned MSCs represent a promising cell-free therapeutic method and highlight miR-150-5p as a novel molecular target for regulating immune hyperactivation during sepsis.

BACKGROUND: Semaphorin 3A (Sema3A) is a member of neural guidance factor family well-known for inducing the collapse of nerve cell growth cone and regulating nerve redistribution. It also has been characterized as an immunoregulatory and tumor promoting factor. Our previous study showed that Sema3A was involved in the regulation of sympathetic innervation and neuropathic pain of endometriosis. Nevertheless, the role of Sema3A in the development of endometriosis and its potential upstreaming factor are still not clear.
METHODS: Histology experiments were carried to detect the expression of Sema3A, hypoxia -inducible factor 1α (HIF-1α) and the distribution of macrophages. Cell experiments were used to explore the effect of Sema3A on the proliferation and migration of endometrial stromal cells (ESCs) and to confirm the regulatory action of HIF-1α on Sema3A. In vivo experiments were carried out to explore the role of Sema3A on the development of endometriosis.
RESULTS: Sema3A was highly expressed in endometriotic lesions and could enhanced the proliferation and migration abilities of ESCs. Aberrant macrophage distribution was found in endometriotic lesions. Sema3A also promoted the differentiation of monocytes into anti-inflammatory macrophages, so indirectly mediating the proliferation and migration of ESCs. Hypoxic microenvironment induced Sema3A mRNA and protein expression in ESCs via HIF-1α. Administration of Sema3A promoted the development of endometriosis in a mouse model.
CONCLUSIONS: Sema3A, which is regulated by HIF-1α, is a promoting factor for the development of endometriosis. Targeting Sema3A may be a potential treatment strategy to control endometriotic lesions.

UNASSIGNED: P2X receptors are a family of homo- and heterotrimeric cation channels gated by extracellular ATP. The P2X4 and P2X7 subunits show overlapping expression patterns and have been involved in similar physiological processes, such as pain and inflammation as well as various immune cell functions. While formation of P2X2/P2X3 heterotrimers produces a distinct pharmacological phenotype and has been well established, functional identification of a P2X4/P2X7 heteromer has been difficult and evidence for and against a physical association has been found. Most of this evidence stems, however, from in vitro model systems.
UNASSIGNED: Here, we used a P2X7-EGFP BAC transgenic mouse model as well as P2X4 and P2X7 knock-out mice to re-investigate a P2X4-P2X7 interaction in mouse lung by biochemical and immunohistochemical experiments as well as quantitative expression analysis.
UNASSIGNED: No detectable amounts of P2X4 could be co-purified from mouse lung via P2X7-EGFP. In agreement with these findings, immuno-histochemical analysis using a P2X7-specific nanobody revealed only limited overlap in the cellular and subcellular localizations of P2X4 and P2X7 in both the native lung tissue and primary cells. Comparison of P2X4 and P2X7 transcript and protein levels in the respective gene-deficient and wild type mice showed no mutual interrelation between their expression levels in whole lungs. However, a significantly reduced P2rx7 expression was found in alveolar macrophages of P2rx4 -/- mice.
UNASSIGNED: In summary, our detailed analysis of the cellular and subcellular P2X4 and P2X7 localization and expression does not support a physiologically relevant direct association of P2X4 and P2X7 subunits or receptors in vivo.