筋膜瓣修复骨缺损时血管化与膜诱导促成骨作用的量化对比研究

目的 比较不同时期筋膜瓣修复骨缺损时血管化与膜诱导促成骨作用,为临床干预骨缺损治疗提供依据.方法 使用含重组人骨形成蛋白2(BMP-2)的骨诱导吸收材料(OAM)与兔骨髓干细胞(BMSC)构建非细胞型组织工程骨,制作兔尺骨骨缺损模型(n=75)并进行组织工程骨移植修复骨缺损.实验兔分为3组:A组(n=25)单纯植入组织工程骨;在骨缺损邻近区域制备1个带蒂筋膜瓣,B组(n=25)植入无蒂筋膜瓣包裹的组织工程骨,C组(n=25)植入带蒂筋膜瓣包裹的组织工程骨.术后第4、8、12、16周行骨修复区内成骨区与空曝区吸光度比测量、骨形态计量分析和血管图像计量分析;术后第8、12、16周进行放射性核素骨显像检查,腋动脉注入墨汁观察修复区血管再生情况.结果 与A组、B组比较,术后第4、8周C组骨修复区内成骨区与空曝区吸光度比、新生骨小梁面积占镜下修复区面积的比值、单位面积内血管再生面积和放射性核素骨显像感兴趣区(ROI)摄取比值均显著增加(均P＜0.05).与术后第8周比较,术后第16周3组骨修复区内成骨区与空曝区吸光度比、新生骨小梁面积占镜下修复区面积的比值均增加(均P＜0.05).术后第8周A组、B组、C组骨修复区单位面积内血管再生面积分别为(7.20±0.23)％、(7.75±0.57)％、(24.75±1.58)％,放射性核素骨显像ROI摄取比值分别为(7.17±0.01)％、(10.12±0.02)％、(29.37±0.04)％;术后第16周A组、B组、C组骨修复区单位面积内血管再生面积分别为(4.31±0.13)％、(4.69±0.12)％、(9.98±0.74)％,放射性核素骨显像ROI摄取比值分别为(5.03±0.01)％、(5.16±0.04)％、(12.75±0.03)％,组内比较显示术后第16周各组单位面积内血管再生面积和放射性核素骨显像ROI摄取比值均减少(均P＜0.05).结论 带蒂筋膜瓣早期以促血管化成骨作用为主,后期以膜诱导成骨作用为主.     

LIGHT is involved in the pathogenesis of rheumatoid arthritis by inducing the expression of pro-inflammatory cytokines and MMP-9 in macrophages

Macrophages play a crucial role in the perpetuation of inflammation and irreversible cartilage damage during the development of rheumatoid arthritis (RA). LIGHT (TNFSF14) and its receptor TR2 (TNFRSF14) are known to have pro-inflammatory activities in foam cells of atherosclerotic plaques. We tested a hypothesis that LIGHT and TR2 are involved in activation of monocyte/macrophages in RA synovium. Immunohistochemical analysis of RA synovial tissue samples revealed that both LIGHT and TR2 are expressed in CD68 positive macrophages. In contrast, synovial tissue samples from osteoarthritis (OA) patients failed to reveal the expression of LIGHT. Expression of TR2 in RA synovial macrophages was also detected using flow cytometry analysis. To identify the role of LIGHT in the functioning of macrophages in RA, we isolated macrophage enriched cells from RA synovial fluid and stimulated them with LIGHT. LIGHT induced expression of matrix metalloproteinase-9 and pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8. These data indicate that LIGHT and TR2 expressed in macrophages are involved in the pathogenesis of RA by inducing the expression pro-inflammatory cytokines and matrix degrading enzymes.     

Gpnmb在小鼠M1和M2型骨髓源性巨噬细胞中表达的差异

目的了解小鼠M1和M2型骨髓源性巨噬细胞（ BMMφs）中非转移性黑色素瘤糖蛋白b（ Gpnmb）表达的差异。方法原代培养小鼠BMMφs,免疫荧光染色F4/80和流式细胞仪检测CD11b鉴定巨噬细胞;用IFN-γ和LPS诱导BMMφs向M1型分化,用IL-4诱导向M2型分化。实时荧光定量PCR检测M1型巨噬细胞标志物（ TNF-α、iNOS）、M2型巨噬细胞标志物（ MMR、Arg-1）和Gpn-mb的mRNA表达;免疫荧光双染色、Western印迹、流式细胞仪检测Gpnmb与MMR的蛋白表达。结果（1）免疫荧光染色结果示BMMφs中F4/80高表达;流式细胞仪检测结果示BMMφs中有（92．7±6．1）％细胞表达CD11b,提示BMMφs培养成功;（2）相对于未分化的M0型BMMφs,TNF-α、iNOS mRNA在M1型BMMφs中高表达（P均＜0．01）,而MMR、Arg-1 mRNA在M2型BMMφs中高表达（P均＜0．01）,提示原代M1、M2型BMMφs分化成功;（3）M2型BMMφs 的Gpnmb mRNA和蛋白表达均较M0型和M1型BMMφs显著增高（P均＜0．01）;免疫荧光双染色及流式细胞仪结果显示,BMMφs中Gpnmb与MMR共表达,在M2型BMMφs中MMR阳性BMMφs有（83．2±9．7）％表达Gpnmb。结论 M2型BMMφs的Gpnmb表达较M1型BMMφs显著增高,提示Gpnmb可能作为鉴别M1、M2型巨噬细胞的标志物,在巨噬细胞的表型分化中起作用。     

Coxiella burnetii, the agent of Q fever, stimulates an atypical M2 activation program in human macrophages

Coxiella burnetii is an obligate intracellular bacterium, responsible for Q fever, which survives in macrophages by interfering with their microbicidal competence. As functional polarization of macrophages is critical for their microbicidal activity, we studied the activation program of monocyte-derived macrophages (MDM) stimulated with C. burnetii. This program was markedly distinct from that induced by lipopolysaccharides (LPS), a canonical inducer of M1 polarization. Indeed, C. burnetii up-regulated the expression of genes associated with M2 polarization, including TGF-beta1, IL-1 receptor antagonist (IL-1ra), CCL18, the mannose receptor and arginase-1, and only up-regulated the expression of two genes associated with M1 polarization, namely IL-6 and CXCL8. In contrast, C. burnetii down-regulated the expression of genes associated with M1 polarization such as TNF, CD80, CCR7 and TLR-2. Functional analyses showed that C. burnetii-stimulated MDM produced high levels of TGF-beta1 and CCL18, and expressed the mannose receptor and arginase-1, the latter being associated with the prevention of nitric oxide production by MDM. Finally, C. burnetii induced the release of IL-6 and CXCL8 at a lower level than LPS-stimulated MDM. Our results suggest that C. burnetii stimulated an atypical M2 activation program that may account for the persistence of C. burnetii in macrophages.     

The liver is populated by a broad spectrum of markers for macrophages. In alcoholic hepatitis the macrophages are M1 and M2

Background

Liver cell injury in alcoholic hepatitis (AH) is in part, due to macrophage generated proinflammatory cytokines i.e., M1, M2a, M2b, and M2c might be involved in ALD. The T cell response to chemokines and cytokines differs not only when M1 and M2 macrophages are compared but even when individual M2 subtypes are profiled.

Purpose

In AH, M1 monocytes in the blood show increased sensitivity in the TNF-α response to LPS. Immunohistochemistry (IHC) studies showed that the liver sinusoids in ALD are abundantly populated by CD163 expressing type 2 macrophages. In this report, we profile many of the molecules associated with M1 and M2 macrophages in livers with AH using IHC.

Methods

Using immunofluorescent antibody-labeling, we profiled the receptors, cytokines and chemokines observed in M1, M2a, M2b, and M2c macrophages in liver biopsies from patients with AH.

Results

The increased CD 163 expression found in previous studies was confirmed as well an additional macrophage phenotypic marker CD206, suggesting that AH pathogenesis at least partially involves M2a and M2c macrophages. TGF-β was found to be robustly over expressed by liver sinusoidal macrophages. Macrophage expression of the phenotypic markers TLR-2, TLR-4 and TLR-8 – found in both M1 and M2 macrophages – as well as the chemokines CCL-1 and CCL-18 was found. However, IRF-4, which is related to IL-4 production and M2a polarization as well as the cytokines CCL-1 and Il-1β and the chemokine CXCL-1 were also observed, suggesting that M2a and M2b also play a role in AH pathogenesis.

Conclusion

Livers with AH show robust macrophage over expression of TGF-β, a growth factor more commonly associated with M2 type macrophages and mostly known for its fibrogenetic properties. However, our immunoprofiling of macrophage over expression also shows that AH is driven by receptors, interferons, and cytokines that are commonly associated not just with M2 macrophages, but with M1 as well. Thus, a complex interplay between different types of macrophages expressing a diverse array of molecules and receptors is involved in AH.     

Composite scaffolds of nano-hydroxyapatite and silk fibroin enhance mesenchymal stem cell-based bone regeneration via the interleukin 1 alpha autocrine/paracrine signaling loop

Composite scaffolds of nano-hydroxyapatite (nHAp) and silk fibroin (SF) have been reported to promote bone regeneration mainly through signaling pathways associated with cell–biomaterial interaction. However, it is unclear whether soluble factors also play a role in osteoinduction with nHAp-SF. In this study, we confirmed the biocompatibility and superior osteoinductivity of nHAp-SF scaffolds versus SF scaffolds both in vitro and on a calvarial defect model in vivo. This was followed by further analysis with microarray assay. The cDNA microarray results identified 247 differentially expressed genes in bone marrow mesenchymal stem cells (BMSCs) cultured on SF-nHAp scaffolds versus SF scaffolds. The greatest disparity in gene expression levels were observed with Il1α and Ilr2. Real-time PCR assay validated the results. The addition of IL-1α into cultures of BMSCs with SF significantly increased both Bmp2 and Ilr2 expression. However, with BMSCs alone, the Il1r2 expression increased substantially, whereas Bmp2 expression exhibited a decrease rather than increase. These data suggested that nHAp may exert osteoinductive effects on BMSCs via the secretion of IL-1α in an autocrine/paracrine fashion, and IL-1α activity could be regulated through the synthesis of IL1R2 by BMSCs upon interaction with nHAp. These results complemented our understanding of the underlying mechanisms of biomaterial osteoinductivity.     

LILRA5 is expressed by synovial tissue macrophages in rheumatoid arthritis,selectively induces pro‐inflammatory cytokines and IL‐10 and is regulated by TNF‐α, IL‐10 and IFN‐γ

Leukocyte immunoglobulin‐like receptor A5 (LILRA5) belongs to a family of receptors known to regulate leukocyte activation. There are two membrane‐bound and two soluble forms of LILRA5. The transmembrane LILRA5 contain a short cytoplasmic domain and a charged arginine residue within the transmembrane region. Cross‐linking of LILRA5 on monocytes induced production of pro‐inflammatory cytokines, suggesting that LILRA5 plays a role in inflammation. However, expression of LILRA5 in diseases with extensive inflammatory component is unknown. Rheumatoid arthritis (RA) is a chronic inflammatory synovitis characterized by unregulated activation of leukocytes leading to joint destruction. Here we demonstrate extensive LILRA5 expression on synovial tissue macrophages and in synovial fluid of patients with active RA but not in patients with osteoarthritis. We also show that LILRA5 associated with the common γ chain of the FcR and LILRA5 cross‐linking induced phosphorylation of Src tyrosine kinases and Spleen tyrosine kinase (Syk). Furthermore, LILRA5 induced selective production of pro‐inflammatory cytokines as well as IL‐10. LILRA5 mRNA and protein expression was tightly regulated by TNF‐α, IL‐10 and IFN‐γ. Increased expression of LILRA5 in rheumatoid tissue, together with its ability to induce key cytokines involved in RA, suggests that this novel receptor may contribute to disease pathogenesis.     

Local suppression of pro-inflammatory cytokines and the effects in BMP-2-induced bone regeneration

The objective of this study is to investigate the effect of local inflammation suppression on the bone regeneration. Gelatin hydrogels incorporating mixed immunosuppressive triptolide-micelles and bone morphogenic protein-2 (BMP-2) were prepared. The controlled release of both the triptolide and BMP-2 from the hydrogels was observed under in vitro and in vivo conditions. When either J774.1 macrophage-like or MC3T3-E1 osteoblastic cells were cultured in the hydrogels incorporating mixed 2.5, 5 or 10 mg of triptolide-micelles and BMP-2, the expression level of pro- and anti-inflammatory cytokines including interleukin (IL)-6 and IL-10 was down-regulated, but the alkaline phosphatase (ALP) activity was promoted compared with those of hydrogels incorporating BMP-2 without triptolide-micelles. When implanted into a critical-sized bone defect of rats, the hydrogels incorporating mixed 2.5 or 5 mg of triptolide-micelles and BMP-2 showed significantly lower number of neutrophils, lymphocytes, macrophages or dendritic and mast cells infiltrated into the defect, and lower expression level of IL-6, TNF-α, and IL-10 than those incorporating BMP-2 without triptolide-micelles. The reduced local inflammation responses at the defects implanted with the hydrogels incorporating mixed 2.5 or 5 mg of triptolide-micelles and BMP-2 subsequently enhanced the bone regeneration thereat. It is concluded that the proper local modulation of inflammation responses is a promising way to achieve the enhanced bone regeneration.     

来那度胺可抑制单核细胞向M2型巨噬细胞分化及相关细胞因子的分泌

目的 探索来那度胺在肿瘤微环境中对于单核细胞向M2型巨噬细胞分化及IL-10、VEGF和TGF-β1水平的影响.方法 密度梯度离心法分离初治淋巴瘤患者及健康志愿者外周血单个核细胞(PBMCs).用Transwel124孔板共培养PBMCs与淋巴瘤细胞系HUT-78,并于共培养体系中加入来那度胺.流式细胞术分析肿瘤相关巨噬细胞(TAM)特征性表型CD68和CD163的表达,ELISA法检测共培养体系细胞因子IL-10、VEGF和TGF-β1的含量.结果 在PBMCs与HUT-78构成的体外共培养体系中加入来那度胺后,CD68+、CD163+、CD68+ CD163+细胞及CD68+ CD163+在CD68+细胞中所占比例均有显著的下降(P＜0.05).加入来那度胺后患者组CD68+ CD163+/CD68+下降程度明显高于健康志愿者(P＜0.05).加入来那度胺的患者共培养组相对于未加来那度胺的共培养组IL-10和VEGF水平均有显著下降(P＜0.01,P＜0.05).结论 来那度胺在PBMCs与淋巴瘤细胞构建的体外共培养体系中能够有效抑制单核细胞向M2型TAM的分化,且能够抑制患者组共培养体系中IL-10、VEGF分泌.     

核转录因子在二氧化硅刺激巨噬细胞产生细胞因子中的作用

目的 探讨二氧化硅(SiO2)刺激巨噬细胞生成肿瘤坏死因子(TNF)-α、转化生长因子(TGF)-β1增多的分子机制及核转录因子Egr-1和NF-κB介导的信号通路在硅肺发生发展中的作用。方法 Egr-1或NF-κB抗体和反义寡核苷酸分别处理巨噬细胞后,用ELISA法检测细胞上清液中TNF-α蛋白的含量;免疫细胞化学链霉素抗生物素蛋白-过氧化物酶(SP)法检测细胞中TGF-β1蛋白的表达;逆转录-聚合酶链反应(RT-PCR)检测TNF-α和TGF-β1mRNA的表达。结果 与非抗体处理组比较,SiO2刺激下抗体处理组巨噬细胞生成TNF-α蛋白和TGF-β1蛋白减少,其mRNA表达也相应下降(P<0.05);与未转染和转染正义寡核苷酸的细胞相比,Egr-1或NF-κB反义寡核苷酸转染细胞后,在SiO2刺激下巨噬细胞生成TNF-α蛋白和TGF-β1蛋白减少,二者mRNA表达也相应下降(P<0.05)。结论 SiO2刺激巨噬细胞生成TNF-α和TGF-β1可能主要是经核转录因子Egr-1和NF-κB介导,Egr-1与NF-κB抗体和反义寡核苷酸的应用可能会导致早期肺泡炎的活动性下降,延缓或阻止肺纤维化的形成。     

Involvement of β1 integrins in the binding and entry of Trypanosoma cruzi into human macrophages

We have investigated the role of integrin molecules in the binding and entry of Trypanosoma cruzi into human macrophages, with the help of monoclonal antibodies (mAb). Addition of Lia 1/2 mAb and in lesser extent of Lia 1/5 mAb, which are both specific for the β₁ subunit of the VLA integrin family, to human macrophages blocked T. cruzi uptake and subsequent replication inside the macrophages. This inhibition correlated with their respective ability to block Fibronectin (Fn) binding to macrophages. Furthermore, another anti-β₁ mAb, Alex 1/4, which binds to a different epitope on the β₁ molecule and was unable to block Fn binding, did not affect T. cruzi invasion. The inhibition by Lia 1/2 and Lia 1/5 was dose dependent and clearly observable with doses as low as 1 μg/ml. Moreover, this inhibition was T. cruzi specific since the Lia 1/2 and Lia 1/5 were unable to block uptake of Leishmania pifanoi or Escherichia coli by human macrophages. In contrast, the TS 1/18 mAb, which blocks ligand binding to β₂ integrin, inhibited entry of L. pifanoi but not of T. cruzi. Finally, mAb specific for the a₄ and a₅ subunits of the two major Fn binding molecules of macrophages (VLA-4 and VLA-5, respectively), either alone or in combination, were poor inhibitors of T. cruzi uptake, suggesting that several members of the VLA family, including VLA-4 and VLA-5, are involved in binding and entry of T. cruzi into macrophages.     

Increasing the pore sizes of bone-mimetic electrospun scaffolds comprised of polycaprolactone, collagen I and hydroxyapatite to enhance cell infiltration

Bone-mimetic electrospun scaffolds consisting of polycaprolactone (PCL), collagen I and nanoparticulate hydroxyapatite (HA) have previously been shown to support the adhesion, integrin-related signaling and proliferation of mesenchymal stem cells (MSCs), suggesting these matrices serve as promising degradable substrates for osteoregeneration. However, the small pore sizes in electrospun scaffolds hinder cell infiltration in vitro and tissue-ingrowth into the scaffold in vivo, limiting their clinical potential. In this study, three separate techniques were evaluated for their capability to increase the pore size of the PCL/col I/nanoHA scaffolds: limited protease digestion, decreasing the fiber packing density during electrospinning, and inclusion of sacrificial fibers of the water-soluble polymer PEO. The PEO sacrificial fiber approach was found to be the most effective in increasing scaffold pore size. Furthermore, the use of sacrificial fibers promoted increased MSC infiltration into the scaffolds, as well as greater infiltration of endogenous cells within bone upon placement of scaffolds within calvarial organ cultures. These collective findings support the use of sacrificial PEO fibers as a means to increase the porosity of complex, bone-mimicking electrospun scaffolds, thereby enhancing tissue regenerative processes that depend upon cell infiltration, such as vascularization and replacement of the scaffold with native bone tissue.     

Mesenchymal stroma cells trigger early attraction of M1 macrophages and endothelial cells into fibrin hydrogels,stimulating long bone healing without long-term engraftment

Implantation of mesenchymal stroma cells (MSCs) is an attractive approach to stimulate closure of large bone defects but an optimal carrier has yet to be defined. MSCs may display trophic and/or immunomodulatory features or stimulate bone healing by their osteogenic activity. The aim of this study was to unravel whether fibrin hydrogel supports early actions of implanted MSCs, such as host cell recruitment, immunomodulation and tissue regeneration, in long bone defects. Female rats received cell-free fibrin or male MSCs embedded in a fibrin carrier into plate-stabilized femoral bone defects. Removed callus was analyzed for host cell invasion (day 6), local cytokine expression (days 3 and 6) and persistence of male MSCs (days 3, 6, 14 and 28). Fibrin–MSC composites triggered fast attraction of host cells into the hydrogel while cell-free fibrin implants were not invaded. A migration front dominated by M1 macrophages and endothelial progenitor cells formed while M2 macrophages remained sparse. Only MSC-seeded fibrin hydrogel stimulated early tissue maturation and primitive vessel formation at day 6 in line with significantly higher VEGF mRNA levels recorded at day 3. Local TNF-α, IL-1β and IL-10 expression indicated a balanced immune cell activity independent of MSC implantation. Implanted MSCs persisted until day 14 but not day 28. Our results demonstrate that fibrin hydrogel is an attractive carrier for MSC implantation into long bone defects, supporting host cell attraction and pro-angiogenic activity. By this angiogenesis, implant integration and tissue maturation was stimulated in long bone healing independent of long-term engraftment of implanted MSCs.     

不明原因习惯性流产患者Th1/Th2型细胞因子的检测

目的 :了解不明原因习惯性流产 (UHA)患者对滋养细胞抗原刺激产生Th1、Th2型细胞因子的水平 ,探讨其在UHA发病中的作用。方法 :选取 5 4例UHA患者 ,35例为未妊娠者 ,为UHA未孕组 ,19例为有UHA病史 ,现在确定妊娠并难免流产者 ,为UHA难免流产组。分别选取 15例正常未孕妇女及正常妊娠者作为对照组。应用酶联免疫吸附法检测未孕各组经滋养细胞抗原刺激的外周血单个核细胞 (PBMC)及妊娠各组PBMC与蜕膜单个核细胞 (DMC)培养上清液中IL 2、IFN γ、IL 4、IL 10的水平。结果 :①在最佳诱导时间下 ,UHA未孕组PBMC产生IL 2、IFN γ的水平明显高于正常未孕组 (P均 <0 0 5 ) ,而IL 4、IL 10水平明显低于正常未孕组 (P均 <0 0 5 )。②UHA难免流产组PBMC及DMC产生的IL 2、IFN γ水平均明显高于正常妊娠组 (P均 <0 0 5 ) ,而IL 4、IL 10水平则明显低于正常妊娠组 ,差异均有显著性 (P均 <0 0 5 )。两组PBMC产生的各细胞因子水平均低于同组DMC ,差异有显著性 (P <0 0 5 )。结论 :UHA患者对滋养细胞抗原产生以Th1型反应为主的免疫应答 ,产生大量Th1型细胞因子 ,导致妊娠丢失。     

Reciprocal regulation of the nitric oxide synthase/arginase balance in mouse bone marrow-derived macrophages by TH 1 and TH 2 cytokines

Activation with lipopolysaccharide induces macrophages to produce the enzymes arginase and nitric oxide (NO) synthase. Both enzymes use as a substrate the amino acid L-arginine, which can be either hydrolyzed by arginase to urea and ornithine or oxidized by NO synthase to NO and citrulline. NO is important in the bactericidal and cytotoxic activities of macrophages. An equivalent functional role of arginase and its products is not known. We tested the induction of arginase in bone marrow-derived macrophages by endogenous mediators that are known to induce NO synthase, such as interferon-γ (IFN-γ), or suppress the induction of this enzyme, such as interleukin (IL)-4, IL-10, and prostaglandin E₂ (PGE₂). We find that PGE₂ and the TH2 cytokines IL-4 and IL-10 are potent inducers of arginase. In contrast, the TH 1 cytokine IFN-γ does not induce arginase. Simultaneous application of both types of mediators leads to reduced induction of both arginase and NO synthase. Exposure of macrophage cultures to inducers of NO synthase exhausts their ability to respond subsequently to inducers of arginase. Conversely, exposure of the cells to inducers of arginase exhausts their ability to respond subsequently to inducers of NO synthase. The results are consistent with a competition of both enzymes for their substrate, L-arginine, with a reciprocal inhibition in the induction of both enzymes, or a combination of both phenomena. The enzymes NO synthase and arginase appear to define two alternate functional states of macrophages, induced by TH 1 and TH 2 cytokines, respectively.     

Expression and function of Na+/Ca2+ exchangers 1 and 3 in human macrophages and monocytes

The Na⁺/Ca²⁺ exchanger (NCX) is a membrane transporter that can switch Na⁺ and Ca²⁺ in either direction to maintain the homeostasis of intracellular Ca²⁺. Three isoforms (NCX1, NCX2, and NCX3) have been characterized in excitable cells, e.g. neurons and muscle cells. We examined the expression of these NCX isoforms in primary human lung macrophages (HLM) and blood monocytes. NCX1 and NCX3, but not NCX2, are expressed in HLM and monocytes at both mRNA and protein levels. Na⁺‐free medium induced a significant increase in intracellular calcium concentration ([Ca²⁺]_i) in both cell types. This response was completely abolished by the NCX inhibitor 5‐(N‐4‐chlorobenzyl)‐20,40‐dimethylbenzamil (CB‐DMB). Moreover, inhibition of NCX activity during Ca²⁺‐signaling induced by histamine caused a delay in restoring baseline [Ca²⁺]_i. Na⁺‐free medium induced TNF‐α expression and release in HLM comparable to that caused by LPS. TNF‐α release induced by Na⁺‐free medium was blocked by CB‐DMB and greatly reduced by RNAi‐mediated knockdown of NCX1. These results indicate that human macrophages and monocytes express NCX1 and NCX3 that operate in a bidirectional manner to restore [Ca²⁺]_i, to generate Ca²⁺‐signals, and to induce TNF‐α production. Therefore, NCX may contribute to regulate Ca²⁺ homeostasis and proinflammatory functions in human macrophages and monocytes.