To clarify the impact of SETD2 on macrophage function in pediatric patients with acute suppurative osteomyelitis and to elucidate the precise underlying mechanism. To gain insights into the potential functions of SETD2, a comprehensive study was conducted utilizing a co-culture model of human bone mesenchymal stem cells (hBMSCs) and bone marrow-derived macrophages (THP-1). A range of techniques were employed, including quantitative polymerase chain reaction, western blotting, ELISA, alkaline phosphatase activity assays, alizarin red S staining, luciferase reporter gene assays, and chromatin immunoprecipitation, to unravel the intricate interactions and molecular mechanisms involving SETD2 in this system. It was observed that SETD2 expression was reduced in THP-1 cells stimulated by staphylococcal protein A (SPA). Furthermore, the downregulation of SETD2 resulted in elevated M1 macrophage polarization and glycolysis, effects that were mitigated by SPA stimulation. Notably, SPA-stimulated THP-1 cells exhibited an increase in HIF-1α expression, which exhibited an inverse correlation with SETD2 levels. Moreover, it was discovered that SETD2 functioned as a catalyst for H3K36me3 and bound to the HIF-1α gene, which, in turn, regulated HIF-1α expression. Furthermore, the suppression of HIF-1α abrogated the consequences of SETD2 downregulation on glycolysis and M1 macrophage polarization. Lastly, the study demonstrated that M1 macrophage polarization serves as a mediator for BMP4’s inhibitory effect on osteogenic differentiation of hBMSCs. This research has uncovered a previously unknown role of SETD2 in macrophages during osteomyelitis, revealing its significance in the pathogenesis of this condition. These findings suggest SETD2 as a novel target for the treatment of osteomyelitis.
Gong Chen,Panyang Gu,Wenfang Wu,Yuan Yin,Liangyu Pan,Shu Huang,Wei Lin,Meichun Deng
Histone methylations play a crucial role in the development of neuropathic pain, and SET domain containing 2 (SETD2), a histone methyltransferase, serves as the sole tri-methylase known to catalyze H3K36me3 at the gene body. The N -methyl- d -aspartate receptor (NMDAR) is activated and mediates excitatory synaptic transmission in neuropathic pain. Nevertheless, the involvement of SETD2 in neuropathic pain and the specific regulatory mechanisms affecting NMDARs remain poorly understood. The expression levels of SETD2 were significantly decreased in the spinal cord and dorsal root ganglion (DRG) of rodents undergoing neuropathic pain induced by sciatic nerve chronic constrictive injury. Lentiviral shRNA-mediated SETD2 knockdown and conditional knockout in sensory neurons caused sustained NMDAR upregulation in DRG and spinal cord, which resulted in heightened neuronal excitability and increased pain hypersensitivity. SETD2 deficiency also led to reduced H3K36me3 deposition within the Grin1 (glutamate ionotropic receptor NMDA type subunit 1) gene body, thereby promoting aberrant transcription of the NMDARs subunit GluN1. The absence of SETD2 in the DRG potentiated neuronal excitability and increased presynaptic NMDAR activity in the spinal dorsal horn. Chromatin immunoprecipitation sequencing targeting H3K36me3 identified NFAT5 as a co-transcription factor in the transcriptional regulation of Grin1 . These findings highlight SETD2 as a key regulator in pain signal transmission and offered new perspectives on the development of analgesics through the targeted modulation of epigenetic mechanisms.
Dentin is a major mineralized component of teeth generated by odontoblasts. Several types of histone methylation have been reported to play important roles in odontoblast differentiation and dentinogenesis. However, the role of methylation on histone 3 at lysine 36 (H3K36) remains enigmatic. Here we find a high expression of SETD2, a methyltransferase catalyzing the trimethylation of H3K36 (H3K36me3), in the odontoblast layer. In vitro knockdown experiments and in vivo observations of two conditional knockout mouse models reveal SETD2 is essential for odontoblast differentiation and dentinogenesis. Integrated analyses of RNA sequencing and spike-in Cleavage Under Targets and Tagmentation sequencing data show SETD2 is crucial for both H3K36me3 occupancy on the loci of Col11a2 and Sema3e and their transcription. Further experiments verify COL11A2 and SEMA3E act upstream of AKT1 signaling, promoting odontoblastic differentiation. In vitro and in vivo activation of AKT1 using SC79 (an AKT activator) partially rescues the impaired odontoblast differentiation caused by Setd2 knockdown or deficiency. Therefore, our findings indicate that H3K36me3 mediated by SETD2 is essential for dentinogenesis through regulating the expression of Col11a2 and Sema3e and AKT1 signaling.
危险品化学品经营许可证（带存储）