巨噬细胞吞噬pRBCs后炎症因子分泌的机制研究

目的体外研究小鼠骨髓诱导巨噬细胞BMDMs吞噬pRBCs后能否形成LC3相关吞噬(LC3-associated phagocytosis,LAP)及其在调节BMDMs分泌炎症因子中的作用。方法 构建BMDMs与pRBCs体外共孵育及吞噬研究平台。体外诱导小鼠BMDMs，用CFSE标记P. y 17XNL感染的小鼠红细胞(parasitized red blood cells,pRBCs)，共孵育后采用流式细胞术观察BMDMs对pRBCs的吞噬效率并选定最佳条件，用CBA法检测培养上清中炎症因子浓度。随后分离诱导巨噬细胞ATG5条件缺失小鼠(Lyz2-Cre-ATG5flox/flox)来源的BMDMs，观察其吞噬pRBCs后胞内ATG5缺失对其分泌炎症因子的影响，通过免疫荧光染色及共聚焦观察ATG5缺失对BMDMs吞噬pRBCs后，胞内LC3-Ⅱ与pRBCs共定位的影响。结果 体外成功诱导BMDMs，流式细胞术检测证实巨噬细胞纯度>95%。在BMDMs与p RBCs按照1∶20孵育下，随孵育时间延长，吞噬比例显著增加，其中孵育4 h时，吞噬比例最高(>50%)。CBA炎症因...     

通过LPS造成小鼠脓毒症模型探讨小鼠腹腔巨噬细胞的自噬在免疫功能变化中的动态意义

目的分析脓毒症模型小鼠腹腔巨噬细胞自噬性能的波动情况。方法生存实验小鼠随机分为WT/LPS组(n=12)以及IRF-1 KO型LPS组(n=12)。向LPS组小鼠腹腔中输入180~230μl LPS(20 mg/kg)。完成LPS输入后的96 h后采集小鼠的生存曲线。其余在体动物实验小鼠分为WT/NS组、WT/LPS组、IRF-1 KO/NS组、IRF-1 KO/LPS组,向LPS组小鼠腹腔中输入180~230μl 20 mg/kg的LPS,向NS组小鼠腹腔输入等量的LPS(20 mg/kg),完成注射12 h后全部处死,采集小鼠肺组织标本和肺泡巨噬细胞、脾脏巨噬细胞及腹腔巨噬细胞。利用免疫荧光染色法对各组小鼠腹腔巨噬细胞中的LC3B颗粒聚集情况进行检测,通过Western blot检测各组小鼠巨噬细胞cleaved caspase-3,LC3-Ⅱ/Ⅰ的表达自噬水平。结果 WT/LPS组的病理组织学出现急性肺损伤的情况,IRF-1 KO/LPS组的急性肺损伤的情况有所减缓;WT/LPS组的小鼠腹腔巨噬细胞以及脾脏巨噬细胞中的cleaved caspase-3蛋白表达水平、LC3-Ⅱ蛋白表达水平、LC3-Ⅱ/Ⅰ的比例均要高于WT/NS组,IRF-1 KO/LPS组的小鼠腹腔巨噬细胞中的cleaved caspase-3蛋白表达水平要低于WT/LPS组,该组LC3-Ⅱ蛋白表达水平、LC3-Ⅱ/Ⅰ的比例、LC3-Ⅰ向LC3-Ⅱ的转化均高于WT/LPS组;通过LPS诱导,WT组小鼠腹腔巨噬细胞线粒体损伤较为严重,IRF-1 KO组小鼠腹腔巨噬细胞产生线粒体自噬的情况;WT/LPS组以及IRF-1 KO/LPS组小鼠腹腔巨噬细胞中的LC3Bd颗粒聚焦程度,分别高于WT/NS组和WT/LPS组,IRF-1 KO组小鼠腹腔巨噬细胞自噬程度比WT组大。结论 IRF-1 KO对脓毒症的预后及脏器炎症有明显的修复作用,LRF-1干扰了小鼠巨噬细胞的凋亡和自噬平衡。     

p-p38 MAPK在A2AR敲除新生小鼠缺氧缺血脑区的表达及意义

 目的：探讨p-p38 MAPK在腺苷A2A受体敲除(A2AR-/-)新生小鼠缺氧缺血脑区的表达及意义。方法：采用改良Rice法建立新生小鼠缺氧缺血性脑损伤（HIBD）模型。A2AR-/-(KO)及同期野生型(A2AR+/+,WT)C57/BL6新生小鼠（7日龄）分别按照完全随机分组方法分成假手术组及模型组,模型组按HIBD后取标本时间不同又分为造模后1 d组、3 d组和7 d组,共8个实验动物组,每组取小鼠8只,共64只。采用TUNEL结合尼氏染色检测神经细胞凋亡,采用免疫组织化学法检测活化caspase-3及p-p38 MAPK表达。同时,KO及同期WT小鼠分别取假手术组（SKO和SWT, n=10)及模型组(MKO和MWT,n=30)于HIBD后1 d同时进行新生鼠短期神经行为学评定。结果：（1）缺氧缺血后皮层及海马CA1区神经细胞凋亡、活化caspase-3及p-p38 MAPK表达均增加,造模后1 d为高峰;（2）A2AR敲除导致神经细胞凋亡及活化caspase-3表达增加,与同一时点的WT小鼠相比均有显著差异（P<0.01）;p-p38 MAPK表达增加,其中,1 d及3 d后2种基因型小鼠间均有显著差异（P<0.01）;（3）Peason相关分析显示,活化caspase-3表达与p-p38 MAPK表达呈显著正相关(皮层：r=0.957, P<0.01;海马CA1区：r= 0.939, P<0.01)。结论：p-p38 MAPK可能参与了A2AR敲除增加新生小鼠脑缺氧缺血后神经细胞凋亡、加重脑损害的过程。     

NF-κB亚基p50在病毒诱导的IFN-β表达中的作用研究

目的探究核因子κB(nuclear factor-κB,NF-κB)家族成员p50的缺失对不同类型病毒诱导的IFN-β(interferonbeta)表达的影响。方法建立小鼠病毒感染模型观察p50-/-小鼠(knockout,KO)和野生小鼠(wild type,WT)生存率;酶联免疫吸附法检测病毒感染后小鼠血清以及骨髓来源巨噬细胞(bone marrow-derived macrophages,BMDMs)上清IFN-β水平。免疫印迹检测IFN-β产生过程中重要转录因子干扰素调节因子(interferon regulatory factor,IRF)的表达和活化。结果致死剂量的病毒感染后,p50-/-小鼠和野生小鼠生存率没有差异;p50的缺失导致病毒感染后小鼠血清和BMDMs培养上清中IFN-β水平轻微降低,IRF7的诱导表达和IRF3的活化在病毒感染早期略有下降。结论 NF-κB家族成员p50促进病毒诱导的IFN-β表达,但作用较小。     

Balb/c小鼠PD-1敲除后抑制疟原虫生长及其机制初探

目的探讨PD-1 KO(knock out)对约氏疟原虫P.y17XL增殖的影响及其可能的作用机制。方法感染约氏疟原虫P.y17XL后,比较WT和PD-1 KO小鼠的存活率及其体内的原虫血症;然后,流式细胞技术检测约氏疟原虫P.y17XL感染能否诱导WT小鼠巨噬细胞、DC、中性粒细胞和活化的CD4+T细胞表面PD-1表达;最后比较感染约氏疟原虫P.y17XL的WT和PD-1 KO小鼠的脾脏CD4+T细胞功能以及血清中的抗体水平。结果与WT小鼠相比,PD-1 KO小鼠的疟原虫增殖明显受到抑制,而且存活率也明显高于感染的WT小鼠;约氏疟原虫P.y17XL感染能诱导WT小鼠巨噬细胞、DC、中性粒细胞和CD4+T细胞表面PD-1的表达;虽然WT和PD-1 KO小鼠的脾脏CD4+T细胞功能没有显著差别,但是PD-1 KO小鼠的血清总IgG水平在感染后第6、8天显著高于WT小鼠。结论 PD-1 KO后能提高感染小鼠的存活率,增强其清除红内期疟原虫的能力;其机制可能与PD-1 KO小鼠血清中抗体水平升高有一定的关系。     

肿瘤相关M2型巨噬细胞通过Toll样受体增强卵巢癌细胞MMP-9的表达

目的 探讨M2型巨噬细胞在卵巢癌侵袭转移中的作用及其可能涉及的Toll样受体(TLRs)信号通路机制.方法 用320 nmol/L佛波醇酯(PMA)诱导THP-1细胞,直接免疫荧光技术鉴定M2型巨噬细胞;Transwell小室建立M2细胞与卵巢癌细胞SKOV3体外非接触式共培养模型;24和48 h共培养后,实时荧光定量聚合酶链式反应(real-time PCR)检测SKOV3内TLR1、2、6和基质金属蛋白酶MMP-9水平,蛋白免疫印记(Western blot)检测MyD88、TRAF6 、P-NF-κB和MMP-9表达;TLR1、2和6激动剂分别作用SKOV3 6、12和24h后评价MMP-9的变化.结果 PMA可诱导THP-1成为M2型巨噬细胞;M2型巨噬细胞与SKOV3共培养24和48 h后,MMP-9的表达水平显著高于对照组(P ＜0.05);TLR1、2、和6于共培养24和48 h后在SKOV3有较高表达(P＜0.05);共培养24和48 h后,TLRs信号通路蛋白MyD88、TRAF6和P-NF-κB在SKOV3也同步表达增高(P ＜0.05);TLR1、2和6激动剂Pam3CSK4、HKLM和FSL-1分别刺激SKOV3 6、12和24 h后MMP-9 mRNA水平有显著高表达(P＜0.05).结论 分化诱导后的M2型巨噬细胞,可能通过刺激和活化TLR1、2、6信号途径,引起卵巢癌细胞SKOV3内基质金属蛋白酶MMP-9水平增加,增强肿瘤的侵袭转移能力.     

活化的蛋白激酶C受体1提高巨噬细胞吞噬能力

目的 探究活化的蛋白激酶C受体1(RACK1)的缺失对骨髓来源的巨噬细胞(BMDMs)吞噬、杀菌能力的影响.方法 构建RACK1髓系条件性敲除小鼠模型,运用流式细胞术检测并比较Rack1△Mye小鼠(knockout,KO)和对照Rack1F/-小鼠(wild type,WT)BMDMs机械吞噬、吞噬细菌、杀灭细菌能力...     

共转录因子CITED1在小鼠骨代谢中的调控作用

目的在体研究CITED1在骨代谢即成骨/破骨平衡中的调节作用,为骨质疏松的治疗提供相应的理论基础。方法利用野生型小鼠(WT小鼠)和构建的CITED1基因敲除小鼠(KO小鼠),显微电子计算机断层扫描(CT)定量测量WT小鼠和KO小鼠股骨长度、骨量和骨皮质以及骨松质厚度等骨骼表型。用ELISA检测骨代谢的血液学相关指标。用RT-qPCR检测骨标志基因的表达,从分子水平探究骨代谢改变的原因。结果 KO小鼠颅骨成骨细胞中CITED1表达极少,表明敲除成功。KO小鼠股骨长度、骨量和骨皮质以及骨松质厚度显著高于WT小鼠。KO小鼠外周血血清中I型原胶原肽(P1NP)、骨钙素(OC)和骨碱性磷酸酶(BALP)浓度均显著高于WT小鼠,而抗酒石酸酸性磷酸酶(TRAP)的浓度显著低于WT小鼠。RT-qPCR结果显示,KO小鼠颅骨成骨细胞中OC和BALP基因表达较WT小鼠显著增加(P<0. 001);同时,KO小鼠颅骨成骨细胞中抗酒石酸酸性磷酸酶(TRAP)的表达较WT小鼠显著降低(P<0. 05)。结论小鼠CITED1敲除后可以通过上调OC和BALP基因表达,下调TRAP基因的表达,促进骨形成,抑制骨吸收。     

CXCL16缺失缓解STZ诱导的糖尿病小鼠的肾脏病变

 目的: 探索CXCL16基因缺失对链脲佐菌素(STZ)引发的糖尿病小鼠肾脏病变的影响。方法: 选取8周龄雄性C57BL/6J CXCL16基因缺失(C16 KO)小鼠,以及相同年龄及背景的野生型(WT)小鼠,采用STZ诱导的方式,建立糖尿病小鼠模型,观察CXCL16基因缺失对糖尿病肾病发生发展的影响。结果: 在糖尿病病变方面,与STZ处理的WT小鼠相比,STZ诱导C16 KO糖尿病小鼠的空腹血糖显著降低,并且其葡萄糖耐受能力得到显著改善。在糖尿病引发的肾脏病变方面,STZ处理后,C16 KO糖尿病小鼠的尿蛋白量显著低于WT糖尿病小鼠,此外,C16 KO糖尿病小鼠的肾小球损伤也明显低于WT糖尿病小鼠。与此同时,与WT糖尿病小鼠相比,C16 KO糖尿病小鼠肾脏组织活性氧簇(ROS)、丙二醛(MDA)、氧化低密度脂蛋白(ox-LDL)水平及凝集素样氧化低密度脂蛋白受体 1(Lox-1)的mRNA表达水平均显著下调。此外,在STZ处理后,C16 KO糖尿病小鼠肾组织中的巨噬细胞移动抑制因子(MIF)、炎症因子TNF-α 和IL-6以及黏附因子ICAM-1和CXCL1的mRNA表达水平均显著低于WT糖尿病小鼠。结论: CXCL16基因缺失能显著抑制STZ诱导的糖尿病小鼠肾脏病变。     

低氧诱导因子-1α siRNA对胶原诱导关节炎小鼠的治疗效果及其对M1型巨噬细胞的抑制作用

目的探讨低氧诱导因子-1α(hypoxia inducible factor-1α, HIF-1α)的小干扰RNA(small interfering RNA, siRNA)载体对胶原诱导关节炎(collagen-induced arthritis, CIA)小鼠的治疗效果及其对巨噬细胞的作用机制。方法对DBA/1小鼠注射牛Ⅱ型胶原建立CIA小鼠模型。建模成功的CIA小鼠分别给予尾静脉注射阴性对照腺病毒和HIF-1α-siRNA腺病毒, 每周1次, 共4周。实验分为空白组、CIA模型组、阴性对照组和HIF-1α-siRNA组。分离培养骨髓来源的巨噬细胞(bone marrow-derived macrophages, BMDMs), RT-PCR检测4组小鼠BMDMs中CD206、精氨酸(arginine, Arg)的相对表达量;流式细胞术检测小鼠脾脏和胸腺中F4/80+CD16/32+M1和F4/80+CD206+M2型巨噬细胞比例;HE染色观察小鼠踝关节的病理变化;免疫组化法检测小鼠滑膜组织中巨噬细胞及其亚型水平。结果 (1)与空白组比较, 模型组小鼠BMDMs中CD206 mRN...     

Beta-arrestin 2 negatively regulates sepsis-induced inflammation

β-arrestins 1 and 2 are ubiquitously expressed proteins that alter signalling by G-protein-coupled receptors. β-arrestin 2 plays an important role as a signalling adaptor and scaffold in regulating cellular inflammatory responses. We hypothesized that β-arrestin 2 is a critical modulator of inflammatory response in experimental sepsis. β-arrestin 2(−/−) and wild-type (WT) mice were subjected to caecal ligation and puncture (CLP). The survival rate was significantly decreased (P < 0·05) in β-arrestin 2(−/−) mice (13% survival) compared with WT mice (53% survival). A second group of mice were killed 18 hr after CLP for blood, peritoneal lavage and tissue sample collection. CLP-induced plasma interleukin (IL)-6 was significantly increased 25 ± 12 fold and caecal myeloperoxidase (MPO) activity was increased 2·4 ± 0·3 fold in β-arrestin 2(−/−) compared with WT mice. β-arrestin 2(−/−) mice exhibited more severe lung damage and higher bacterial loads compared with WT mice post CLP challenge as measured by histopathology and colony-forming unit count. In subsequent experiments, splenocytes, peritoneal macrophages and bone marrow-derived macrophages (BMDMs) were isolated and cultured from β-arrestin 2(−/−) and WT mice and stimulated in vitro with lipopolysaccharide (LPS). Tumour necrosis factor (TNF)-α, IL-6 and IL-10 production induced by LPS was significantly augmented (2·2 ± 0·2 fold, 1·8 ± 0·1 fold, and 2·2 ± 0·4 fold, respectively; P < 0·05) in splenocytes from β-arrestin 2(−/−) mice compared with WT mice. The splenocyte response was different from that of peritoneal macrophages or BMDMs, which exhibited no difference in TNF-α and IL-6 production upon LPS stimulation between WT and β-arrestin 2(−/−) mice. Our data demonstrate that β-arrestin 2 functions to negatively regulate the inflammatory response in polymicrobial sepsis.     

Role of matrix metalloproteinase-7 in the modulation of a Chlamydia trachomatis infection

To determine the role of matrix metalloproteinase-7 (MMP-7) in the pathogenesis of chlamydial infection, C57BL/6 wild-type (WT) and MMP-7 knockout (KO) mice were infected intravaginally with Chlamydia trachomatis mouse pneumonitis (MoPn). Over a period of 6 weeks postinfection, various organs were cultured for C. trachomatis. Other infected animals were mated to assess their fertility status. No significant differences were observed between WT and KO mice in the number of animals with positive vaginal cultures, length of time of C. trachomatis shedding, or the number of C. trachomatis inclusion-forming units (IFU) recovered from their genital tracts. Likewise, the number of animals with hydrosalpinx, and the fertility rates and the number of embryos per mouse, were similar in WT and KO mice. Cultures from the spleen, lungs, kidneys and large intestine yielded similar numbers of IFU from WT and KO mice. However, the number of C. trachomatis IFU recovered from the small intestine of KO mice was significantly higher than that recovered from the small intestine of WT mice at 2 weeks postinfection. Because MMP-7 KO mice are deficient in active intestinal alpha-defensins, the results suggest that these components play a role in regulating colonization of the gastrointestinal tract by Chlamydia. By contrast, MMP-7 is dispensable in the progression and resolution of the genital tract infection.     

The CaSR/TRPV4 coupling mediates pro-inflammatory macrophage function

Aim

Although calcium-sensing receptor (CaSR) and transient receptor potential vanilloid 4 (TRPV4) channels are functionally expressed on macrophages, it is unclear if they work coordinately to mediate macrophage function. The present study investigates whether CaSR couples to TRPV4 channels and mediates macrophage polarization via Ca²⁺ signaling.

Methods

The role of CaSR/TRPV4/Ca²⁺ signaling was assessed in lipopolysaccharide (LPS)-treated peritoneal macrophages (PMs) from wild-type (WT) and TRPV4 knockout (TRPV4 KO) mice. The expression and function of CaSR and TRPV4 in PMs were analyzed by immunofluorescence and digital Ca²⁺ imaging. The correlation factors of M1 polarization, CCR7, IL-1β, and TNFα were detected using q-PCR, western blot, and ELISA.

Results

We found that PMs expressed CaSR and TRPV4, and CaSR activation-induced marked Ca²⁺ signaling predominately through extracellular Ca²⁺ entry, which was inhibited by selective pharmacological blockers of CaSR and TRPV4 channels. The CaSR activation-induced Ca²⁺ signaling was significantly attenuated in PMs from TRPV4 KO mice compared to those from WT mice. Moreover, the CaSR activation-induced Ca²⁺ entry via TRPV4 channels was inhibited by blocking phospholipases A2 (PLA2)/cytochromeP450 (CYP450) and phospholipase C (PLC)/Protein kinase C (PKC) pathways. Finally, CaSR activation promoted the expression and release of M1-associated cytokines IL-1β and TNFɑ, which were attenuated in PMs from TRPV4 KO mice.

Conclusion

We reveal a novel coupling of the CaSR and TRPV4 channels via PLA2/CYP450 and PLC/PKC pathways, promoting a Ca²⁺-dependent M1 macrophage polarization. Modulation of this coupling and downstream pathways may become a potential strategy for the prevention/treatment of immune-related disease.     

Effective clearance of intracellular Leishmania major in vivo requires Pten in macrophages

Leishmaniases are a major international public health problem, and macrophages are crucial for host resistance to this parasite. To determine if phosphatase and tensin homologue deleted on chromosome ten (Pten), a negative regulator of the PI3K pathway, plays a role in macrophage-mediated resistance to Leishmania, we generated C57BL/6 mice lacking Pten specifically in macrophages (LysMCrePten(flox/flox) mice). Examination of lesions resulting from Leishmania major infection showed that LysMCrePten(flox/flox) mice were more susceptible to the parasite than wild-type (WT) mice in the early phase of the infection, but were eventually able to eliminate the pathogen. In vitro Pten-deficient macrophages showed a reduced ability to kill parasites in response to IFN-gamma treatment, possibly because the mutant cells exhibited decreased TNF secretion that correlated with reductions in inducible nitric oxide synthase expression and nitric oxide production. In response to various TLR ligands, Pten-deficient macrophages produced less TNF and IL-12 but more IL-10 than WT cells. However, analysis of cells in the lymph nodes draining L. major inoculation sites indicated that both LysMCrePten(flox/flox) and WT mice developed normal Th1 responses following L. major infection, in line with the ability of LysMCrePten(flox/flox) mice to eventually eliminate the parasite. Our results indicate that the efficient clearance of intracellular parasites requires Pten in macrophages.     

PTEN/PI3k/AKT Regulates Macrophage Polarization in Emphysematous mice

Macrophages play an important role in the pathogenesis of COPD. Macrophage polarization towards the M2 phenotype has been observed in the lung tissues of COPD patients and cigarette smokers. The molecular basis of this process remains unclear, and it has not been completely illuminated in animal models of emphysema. In our study, we combined cigarette smoke (CS) exposure with intraperitoneal injection of cigarette smoke extract (CSE) to build an emphysema model. We found by immunohistochemical staining and flow cytometry that the expression level of CD206 and the ratio of M2 to M1 macrophages was increased in emphysematous mice. We also demonstrated that decreased protein level for phosphatase and tensin homology deleted on chromosome ten (PTEN) and increased total protein levels for phosphorylation ‐protein kinase B (p‐AKT) in the lung tissue of emphysematous mice and in CSE‐treated RAW264.7 cells. In both bone marrow‐derived macrophages (BMDMs) from emphysematous mice and CSE‐treated RAW264.7 cells, we observed by RT‐PCR that the mRNA levels of M2 macrophage‐related markers and cytokines were increased. Furthermore, M1 macrophage‐related markers and cytokines were decreased. Meanwhile we treated BMDMs from emphysematous mice and CSE‐treated RAW264.7 cells with the phosphoinositide 3‐kinase (PI3K)/Akt inhibitor (LY294002), we observed a reduction in RNA levels of M2 macrophage‐related markers and cytokines. In conclusion, we confirmed that macrophage M2 polarization was induced in emphysematous mice generated by CS exposure combined with intraperitoneal injection of CSE. We also showed that M2 polarization was mediated through PTEN/PI3k/AKT pathway activation.     

The PPAR-γ agonist pioglitazone modulates inflammation and induces neuroprotection in parkinsonian monkeys

Background and Purpose

Oligodendrocyte (OL) death is important in focal cerebral ischemia. TIMP-3 promotes apoptosis in ischemic neurons by inhibiting proteolysis of TNF-α superfamily of death receptors. Since OLs undergo apoptosis during ischemia, we hypothesized that TIMP-3 contributes to OL death.

Methods

Middle cerebral artery occlusion (MCAO) was induced in Timp-3 knockout (KO) and wild type (WT) mice with 24 or 72 h of reperfusion. Cell death in white matter was investigated by stereology and TUNEL. Mature or immature OLs were identified using antibodies against glutathione S-transferase-π (GST-π) and galactocerebroside (GalC), respectively. Expression and level of proteins were examined using immunohistochemistry and immunoblotting. Protein activities were determined using a FRET peptide.

Results

Loss of OL-like cells was detected at 72 h only in WT ischemic white matter where TUNEL showed greater cell death. TIMP-3 expression was increased in WT reactive astrocytes. GST-π was reduced in ischemic white matter of WT mice compared with WT shams with no difference between KO and WT at 72 h. GalC level was significantly increased in both KO and WT ischemic white matter at 72 h. However, the increase in GalC in KO mice was significantly higher than WT; most TUNEL-positive cells in ischemic white matter expressed GalC, suggesting TIMP-3 deficiency protects the immature OLs from apoptosis. There were significantly higher levels of cleaved caspase-3 at 72 h in WT white matter than in KO. Greater expression of MMP-3 and -9 was seen in reactive astrocytes and/or microglia/macrophages in WT at 72 h. We found more microglia/macrophages in WT than in KO, which were the predominant source of increased TNF-α detected in the ischemic white matter. TACE activity was significantly increased in ischemic WT white matter, which was expressed in active microglia/macrophages and OLs.

Conclusions

Our results suggested that focal ischemia leads to proliferation of immature OLs in white matter and that TIMP-3 contributes to a caspase-3-dependent immature OL death via TNF-α-mediated neuroinflammation. Future studies will be needed to delineate the role of MMP-3 and MMP-9 that were increased in the Timp-3 wild type.     

Galectin-3 deficiency enhances type 2 immune cell-mediated myocarditis in mice

Experimental autoimmune myocarditis (EAM) is a mouse model of immune-mediated myocarditis and cardiomyopathy. The role of Galectin-3 (Gal-3), a β-galactoside-binding lectin, in autoimmune myocarditis has not been studied. Therefore, the aim of this study was to delineate the role of Gal-3 in myosin peptide-induced autoimmune myocarditis in mice. EAM was induced in relatively resistant C57BL/6J mice (wild type, WT) and in mice with a targeted deletion of Gal-3 gene (Gal-3KO) by immunization with myosin peptide MyHCα_334–352. Gal-3KO mice developed more severe myocarditis and more pronounced heart hypertrophy than WT mice. Increased infiltration of CD45⁺ leucocytes, CD3⁺ T cells, F4/80⁺ macrophages, and eosinophils was observed in hearts of Gal-3KO mice compared to WT mice on day 21 after EAM induction. Moreover, hearts of Gal-3KO mice had more T helper type 2 (Th2) cells, alternatively activated M2 macrophages, higher amounts of IgG deposits, and higher serum levels of IL-4 and IL-33 than WT mice. Ablation of Gal-3 in Th1-dominant C57BL/6J mice that are relatively resistant to EAM resulted in more severe disease characterized by type 2 cardiac inflammation. The complex effects of Gal-3 on EAM progression might be important in the consideration of therapeutic options for the treatment of EAM.