Department of Medicine, University of Alberta, Edmonton, AB T5N 2S2, Canada.
Department of Medical Microbiology & Immunology, University of Alberta, Edmonton, AB T5N 2S2, Canada.
Proc Natl Acad Sci U S A. 2024 Feb 20;121(8):e2315653121. doi: 10.1073/pnas.2315653121. Epub 2024 Feb 12.
Monkeypox virus (MPXV) infections in humans cause neurological disorders while studies of MPXV-infected animals indicate that the virus penetrates the brain. Pyroptosis is an inflammatory type of regulated cell death, resulting from plasma membrane rupture (PMR) due to oligomerization of cleaved gasdermins to cause membrane pore formation. Herein, we investigated the human neural cell tropism of MPXV compared to another orthopoxvirus, vaccinia virus (VACV), as well as its effects on immune responses and cell death. Astrocytes were most permissive to MPXV (and VACV) infections, followed by microglia and oligodendrocytes, with minimal infection of neurons based on plaque assays. Aberrant morphological changes were evident in MPXV-infected astrocytes that were accompanied with viral protein (I3) immunolabelling and detection of over 125 MPXV-encoded proteins in cell lysates by mass spectrometry. MPXV- and VACV-infected astrocytes showed increased expression of immune gene transcripts (, and ). However, MPXV infection of astrocytes specifically induced proteolytic cleavage of gasdermin B (GSDMB) (50 kDa), evident by the appearance of cleaved N-terminal-GSDMB (30 kDa) and C-terminal- GSDMB (18 kDa) fragments. GSDMB cleavage was associated with release of lactate dehydrogenase and increased cellular nucleic acid staining, indicative of PMR. Pre-treatment with dimethyl fumarate reduced cleavage of GSDMB and associated PMR in MPXV-infected astrocytes. Human astrocytes support productive MPXV infection, resulting in inflammatory gene induction with accompanying GSDMB-mediated pyroptosis. These findings clarify the recently recognized neuropathogenic effects of MPXV in humans while also offering potential therapeutic options.
猴痘病毒（MPXV）感染人类会引起神经系统疾病，而对感染 MPXV 的动物的研究表明，该病毒会穿透大脑。细胞焦亡是一种炎症性的细胞程序性死亡，是由于被切割的 GSDM 寡聚化导致细胞膜破裂（PMR）而引起的膜孔形成。在此，我们研究了 MPXV 相对于另一种正痘病毒——牛痘病毒（VACV）对人类神经细胞的嗜性，以及它对免疫反应和细胞死亡的影响。MPXV（和 VACV）在星形胶质细胞中的感染性最强，其次是小胶质细胞和少突胶质细胞，基于噬斑测定，神经元的感染性最小。在 MPXV 感染的星形胶质细胞中观察到明显的形态学改变，这些改变伴随着病毒蛋白（I3）免疫标记和通过质谱法在细胞裂解物中检测到超过 125 种 MPXV 编码蛋白。MPXV 和 VACV 感染的星形胶质细胞显示免疫基因转录物的表达增加（、和）。然而，MPXV 感染星形胶质细胞特异性诱导了 GSDMB 的蛋白水解切割（50 kDa），这可以通过出现切割的 N 端-GSDMB（30 kDa）和 C 端-GSDMB（18 kDa）片段来证明。GSDMB 切割与乳酸脱氢酶的释放和细胞内核酸染色增加有关，提示 PMR。富马酸二甲酯预处理可减少 MPXV 感染星形胶质细胞中 GSDMB 的切割和相关的 PMR。人星形胶质细胞支持 MPXV 的有效感染，导致炎症基因诱导，伴随 GSDMB 介导的细胞焦亡。这些发现阐明了 MPXV 在人类中最近被认识到的神经病理学作用，同时也提供了潜在的治疗选择。
