摘要目的:分析多发性骨髓瘤（MM）患者的血小板（PLT）及其线粒体特征，并探讨PLT线粒体呼吸对MM细胞增殖、代谢和线粒体动力学的影响。方法:收集2020年1月至2023年12月四川省人民医院健康志愿者及新诊断MM（NDMM）患者外周血并分离PLT，通过扫描电镜、透射电镜和流式细胞术评估PLT活化状态和线粒体活性氧水平，采用酶联免疫吸附试验（ELISA）检测血清中PLT相关因子表达水平。将健康志愿者未处理的PLT、鱼藤酮或寡霉素预处理PLT分别与MM细胞（RPMI 8226和U266细胞系）共培养。通过CCK-8检测MM细胞增殖，实时荧光定量PCR（qPCR）检测MM细胞中代谢与线粒体动力学相关基因的mRNA表达水平。Western blot检测动力学相关蛋白1（Drp1）及其磷酸化蛋白表达水平。结果:与健康志愿者相比，MM患者的PLT活化标志物CD41/CD61表达升高[（2.10±1.15）%对（0.22±0.19）%， P＝0.048]，CD42b表达下降[（52.80±8.73）%对（74.58±5.11）%， P＝0.020]，且PLT线粒体活性氧水平上升（150.50±17.79对62.45±21.34， P＝0.001）；血清因子检测显示，MM患者中白细胞介素（IL）-34、血小板因子4（PF4）表达下调，碱性成纤维细胞生长因子（bFGF）、胰岛素样生长因子-1（IGF-1）、IL-6、P-选择素、血小板衍生生长因子（PDGF）和转化生长因子-β1（TGF-β1）表达均上调（ P值均<0.05），而血管内皮生长因子（VEGF）水平差异无统计学意义（ P＝0.086）。体外共培养实验表明，与PLT共培养48 h可促进MM细胞增殖，而经鱼藤酮或寡霉素预处理的PLT则丧失促增殖作用（ P值均<0.001）。qPCR结果显示，共培养后MM细胞代谢相关基因柠檬酸合酶（CS）、乳酸脱氢酶（LDHA）及线粒体动力学相关基因动力蛋白-1样蛋白（DNM1L）、线粒体分裂蛋白1（FIS1）mRNA表达水平均升高（ P值均<0.05）。Drp1抑制剂Mdivi-1预处理可抑制MM细胞DNM1L mRNA表达（0.75±0.16对1.00±0.09， P＝0.002），而与PLT共培养后可逆转抑制作用（1.02±0.13对0.75±0.16， P＝0.007）。Western blot结果显示，与PLT共培养后，U266细胞系中p-Drp1 Ser616蛋白表达水平升高（ P<0.05）。 结论:体外实验提示，PLT及其线粒体呼吸功能可能参与调控MM细胞的增殖、代谢重编程及线粒体动力学过程。然而，其在体内环境及临床实践中的相关性与适用性仍需通过更多临床前及临床研究加以验证。

abstractsObjective:To analyze platelet (PLT) characteristics and mitochondrial features in patients with multiple myeloma (MM) , and to investigate the impact of PLT mitochondrial respiration on MM cell proliferation, metabolism, and mitochondrial dynamics.Methods:Peripheral blood was collected from healthy volunteers and newly diagnosed MM (NDMM) patients at Sichuan Provincial People's Hospital between January 2020 and December 2023, and PLTs were isolated. PLT activation and mitochondrial reactive oxygen species (ROS) levels were assessed by scanning and transmission electron microscopy and flow cytometry. Serum levels of PLT-related factors were measured by enzyme-linked immunosorbent assay (ELISA) . MM cell lines (RPMI 8226 and U266) were co-cultured with untreated PLTs from healthy volunteers or with PLTs pretreated with rotenone or oligomycin. MM cell proliferation was assessed by the CCK-8 assay. mRNA expression of metabolism- and mitochondrial dynamics-related genes in MM cells was quantified by real-time quantitative PCR (qPCR) . Drp1 and phosphorylated Drp1 were analyzed by Western blot.Results:Compared with healthy volunteers, MM patients showed increased expression of the PLT activation marker CD41/CD61 [ (2.10 ± 1.15) % vs (0.22 ± 0.19) % , P=0.048], decreased CD42b expression [ (52.80 ± 8.73) % vs (74.58 ± 5.11) % , P=0.020], and elevated mitochondrial ROS levels in PLTs (150.50 ± 17.79 vs 62.45 ± 21.34, P=0.001) . Serum factor analysis showed reduced levels of interleukin-34 (IL-34) and platelet factor 4 (PF4) and increased levels of basic fibroblast growth factor (bFGF) , insulin-like growth factor 1 (IGF-1) , IL-6, P-selectin, platelet-derived growth factor (PDGF) , and transforming growth factor β1 (TGF-β1) in MM patients (all P<0.05) , whereas vascular endothelial growth factor (VEGF) levels did not differ significantly ( P=0.086) . In vitro co-culture experiments showed that co-culture with PLTs for 48 h promoted MM cell proliferation, whereas PLTs pretreated with rotenone or oligomycin lost this pro-proliferative effect (all P<0.001) . qPCR showed that co-culture increased mRNA expression of the metabolism-related genes citrate synthase (CS) and lactate dehydrogenase A (LDHA) and the mitochondrial dynamics related genes dynamin-1-like protein (DNM1L) and mitochondrial fission 1 (FIS1) in MM cells (all P<0.05) . Pretreatment with the Drp1 inhibitor Mdivi-1 inhibited DNM1L mRNA expression in MM cells (0.75 ± 0.16 vs 1.00 ± 0.09, P=0.002) ; this inhibition was reversed by subsequent co-culture with PLTs (1.02 ± 0.13 vs 0.75 ± 0.16, P=0.007) . Western blot analysis showed that co-culture with PLTs increased p-Drp1 (Ser616) protein levels in U266 cells ( P<0.05) . Conclusion:In vitro experiments suggest that PLTs and their mitochondrial respiratory function may be involved in regulating MM cell proliferation, metabolic reprogramming, and mitochondrial dynamics. However, their relevance and applicability in vivo and in clinical practice require further validation in additional preclinical and clinical studies.