乳腺微钙化促进乳腺癌骨转移的研究进展

乳腺癌是女性发病率最高的癌症,在过去的十年中,全球发病率持续上升,死亡率高居不下。最新的统计学研究表明,仅2018年,全球范围内检测出约210万乳腺癌病例,其中近63万患者死亡,因而也是女性死亡率最高的癌症^[1]。然而,许多癌症患者的死亡并非由于肿瘤在原发部位生长,而是在于肿瘤侵袭或转移至其他部位,其中乳腺癌最容易发生骨转移^[2]。在临床上,骨转移常给患者带来极大的痛苦,严重影响患者生活质量。     

运动重置骨骼肌生物钟调控线粒体质量控制的研究进展

<正>昼夜节律是指生物体的行为、生理和生化反应呈现出近24 h的节律活动,这些节律受生物钟系统控制调节。流行病学调查表明,长时间的光照或轮班工作扰乱了生物钟系统,导致生物钟基因节律性表达出现紊乱,不仅增加了罹患肿瘤^[1]、心血管疾病^[2]、糖尿病及肥胖等代谢系统疾病^[3]的风险,也可能造成骨骼肌质量^[4]及运动能力下降^[5]。     

巨噬细胞铁超载在动脉粥样硬化中的研究进展

<正>动脉粥样硬化性心血管疾病(atherosclerotic car-diovascular disease, ASCVD)是目前全球主要死因之一，据世界卫生组织报告估计，每年有1 790万人死于心血管疾病，占所有死亡人数的32%^[1-2]。动脉粥样硬化(atherosclerosis, AS)是ASCVD最主要的病理学改变。它的发生和发展涉及脂质堆积、氧化应激、炎症以及血管和血细胞功能障碍，最终可能导致其临床并发症-诸如心肌梗死和中风等^[3-5]。     

肺癌骨转移治疗中纳米材料应用的研究进展

<正>根据世界卫生组织国际癌症研究机构(IARC)发布的“2020年全球新发癌症病例”报道,全球肺癌新发病例约220万例,死亡约180万例,肺癌是癌症死亡的主要原因。肺癌骨转移发生率为30%～40%,46%的肺癌骨转移患者并发疼痛、高钙血症、病理性骨折等骨相关事件(SRE)^[1,2]。     

转移性乳腺癌生物学标志物检测：2022版ASCO指南解读

<正>乳腺癌是女性最常见的恶性肿瘤，每年新增病例约230万(11.7%)^[1],其中3%～8%的乳腺癌患者初诊时已发生转移^[2],早期患者即使采用手术及规范治疗，仍有30%～40%的患者发生复发转移。转移性乳腺癌(metastatic breast cancer, MBC)患者预后差，5年生存率仅为20%^[2]。虽然MBC临床难以治愈，但可通过新型治疗药物的研发、治疗模式的优化来缓解患者的临床症状，改善患者的生活质量，进一步延长患者的生存期。     

比较两种固定液过度固定乳腺癌组织对FISH法检测HER2基因的影响

<正>FISH技术常用于检测和定位染色体上特定的DNA序列^[1],有利于病理鉴别诊断^[2]、指导临床靶向用药^[3]和监测肿瘤的复发^[4]。组织标本的前处理对确保临床检验结果的准确性尤为重要,固定是组织处理中最重要的环节,也是整个制片过程中最无法补救的一步^[5],组织过度固定或固定不足均会对检测结果造成影响^[6]。乳腺癌穿刺样本,在离体后即加入固定液中保存,由于周末节假日等原因,部分样本未能及时送至病理科,穿刺组织体积较小易出现固定过度,在制片中常存在消化难和杂交背景亮等问题。     

脂噬抑制细胞泡沫化在动脉粥样硬化中作用的研究进展

<正>动脉粥样硬化(atherosclerosis, AS)是多数心脑血管疾病致死的重要原因之一。全球疾病研究表明,AS性心脏病在全球流行,发病数已由1990年的约1亿例增长为2019年的1.8亿例^[1];在2020年流行病调查中发现30岁以上颈动脉内膜增厚的比率为27.6%^[2]。同时,国家心血管病中心发布的《中国心血管健康与疾病报告2021》中指出我国心血管病人数达3.3亿,每5例死亡中就有2例死于心血管病。     

YTHDC1 m6A修饰调控与疾病发病机制的研究进展

<正>表观遗传学是指DNA序列不变的情况下，基于非基因序列改变所致的基因表达水平的变化^[1]，如DNA甲基化^[2]、RNA甲基化^[3]、组蛋白修饰^[4]、染色质构象变化^[5]等。表观遗传学在真核生物中的变化主要是调控细胞增殖^[6-7]、分化^[8]、代谢^[3,9]、周期循环^[10]以及免疫调控^[11]等生物学过程，这一过程中通过某些调控分子量的变化或发生结构修饰变化等，进而靶向调节下游靶基因的生物学效应。     

同一批次外周血BRCA基因二代测序检测出现多个相同突变的原因

<正>二代测序检测具有对一份标本同时检测多基因、多位点、多种变异类型的明显优势^[1],BRCA基因的致病性变异与乳腺癌、卵巢癌等肿瘤的发生密切相关，同时还是PARA抑制剂治疗相关的生物学标志物^[2]。针对BRCA1/2基因有无热点变异，国内对BRCA1/2基因的检测一般采用二代测序高通量测序方法^[3]。我科在日常检测工作中出现新的BRCA基因二代测序数据分析问题，现介绍如下。     

T细胞耗竭发生机制及其在免疫治疗中的研究进展

肿瘤治疗是现今世界最主要的医学难题之一,据2019年肿瘤统计年鉴报道,世界约有176万肿瘤新发和60万死亡病例,肿瘤也是美国的第二大死亡原因。在肿瘤病程中,由于抗原的持续性刺激,CD8⁺T细胞逐渐分化为耗竭T细胞,其特征是抑制性受体的积累、效应功能的降低和增殖能力的下降。由于T细胞耗竭对控制肿瘤发生与发展非常重要,近些年来,有关T细胞耗竭的研究发展迅猛,尤其是发现了PD-1⁺TCF1⁺CD8⁺祖细胞群以及胸腺细胞选择相关高迁移率族蛋白（thymocyte selection-associated high mobility group box, TOX）在T细胞耗竭表观遗传方面的重要性,这些内容对深入理解肿瘤免疫过程以及改善免疫治疗方案有着十分重要的意义。文章就T细胞耗竭的发生机制、表观遗传调控以及逆转方法的相关研究进展作一综述。     

Functional role of Alix in HIV-1 replication

Retroviral Gag proteins encode small peptide motifs known as late domains that promote the release of virions from infected cells by interacting directly with host cell factors. Three types of retroviral late domains, with core sequences P(T/S)AP, YPX_nL, and PPPY, have been identified. HIV-1 encodes a primary P(T/S)AP-type late domain and an apparently secondary late domain sequence of the YPX_nL type. The P(T/S)AP and YPX_nL motifs interact with the endosomal sorting factors Tsg101 and Alix, respectively. Although biochemical and structural studies support a direct binding between HIV-1 p6 and Alix, the physiological role of Alix in HIV-1 biology remains undefined. To elucidate the function of the p6–Alix interaction in HIV-1 replication, we introduced a series of mutations in the p6 Alix binding site and evaluated the effects on virus particle production and virus replication in a range of cell types, including physiologically relevant primary T cells and macrophages. We also examined the effects of the Alix binding site mutations on virion morphogenesis and single-cycle virus infectivity. We determined that the p6–Alix interaction plays an important role in HIV-1 replication and observed a particularly severe impact of Alix binding site mutations when they were combined with mutational inactivation of the Tsg101 binding site.     

Human monocytes kill M-CSF-expressing glioma cells by BK channel activation

In this study, human monocytes/macrophages were observed to kill human U251 glioma cells expressing membrane macrophage colony-stimulating factor (mM-CSF) via a swelling and vacuolization process called paraptosis. Human monocytes responded to the mM-CSF-transduced U251 glioma cells, but not to viral vector control U251 glioma cells (U251-VV), by producing a respiratory burst within 20 min. Using patch clamp techniques, functional big potassium (BK) channels were observed on the membrane of the U251 glioma cell. It has been previously reported that oxygen indirectly regulates BK channel function. In this study, it was demonstrated that prolonged BK channel activation in response to the respiratory burst induced by monocytes initiates paraptosis in selected glioma cells. Forced BK channel opening within the glioma cells by BK channel activators (phloretin or pimaric acid) induced U251 glioma cell swelling and vacuolization occurred within 30 min. U251 glioma cell cytotoxicity, induced by using BK channel activators, required between 8 and 12 h. Swelling and vacuolization induced by phloretin and pimaric acid was prevented by iberiotoxin, a specific BK channel inhibitor. Confocal fluorescence microscopy demonstrated BK channels co-localized with the endoplasmic reticulum and mitochondria, the two targeted organelles affected in paraptosis. Iberiotoxin prevented monocytes from producing death in mM-CSF-expressing U251glioma cells in a 24 h assay. This study demonstrates a novel mechanism whereby monocytes can induce paraptosis via the disruption of internal potassium ion homeostasis.     

Sendai virus budding in the course of an infection does not require Alix and VPS4A host factors

Closing the Sendai virus C protein open reading frames (rSeV-DeltaC virus) results in the production of virus particles with highly reduced infectivity. Besides, the Sendai virus C proteins interact with Alix/AIP1 and Alix suppression negatively affects Sendai virus like particle (VLP) budding. Similarly, the Sendai virus M protein has been shown to interact with Alix. On this basis, it has been suggested that Sendai virus budding involves recruitment of the multivesicular body formation machinery. We follow, here, the production of SeV particles upon regular virus infection. We find that neither Alix suppression nor dominant negative-VPS4A expression, applied separately or in combination, affects physical or infectious virion production. This contrasts with the observed decrease of SV5 virion production upon dominant negative-VPS4A expression. Finally, we show that suppression of more than 70% of a GFP/C protein in the background of a rSeV-DeltaC virus infection has no effect either on SeV particle production or on virus particle infectivity. Our results contrast with what has been published before. Possible explanations for this discrepancy are discussed.     

Early increase of apoptosis-linked gene-2 interacting protein X in areas of kainate-induced neurodegeneration

Apoptosis-linked gene-2 interacting protein X (Alix) is thought to be involved in both cell death and vesicular trafficking. We examined Alix expression 2 h, 6 h and 24 h after triggering seizure-dependent neuronal death by i.p. kainic acid injection. In the hippocampus, intense, transient immunolabelling was observed in the strata lucidum, oriens and radiatum, areas of high synaptic activity. The similarity of this distribution to those of synaptophysin and endophilin suggests a presynaptic localisation. Alix labelling was increased in neuronal cell bodies in kainate-sensitive regions before or concomitant with the first signs of oedema and/or neuronal eosinophilia. The increase persisted 24 h after kainate-injection in CA3 and the piriform cortex which are areas with massive swelling and numerous pyknotic neurons. This suggests that Alix may play an early role in the mechanisms leading to cell death. Taken together, our results suggest that Alix may be a molecular link between synaptic functioning and neuronal death.     

Recruitment of Alix/AIP1 to the plasma membrane by Sendai virus C protein facilitates budding of virus-like particles

Sendai virus (SeV) is unique in that one of the viral accessory proteins, C, enhances budding of virus-like particles (VLPs) formed by SeV matrix protein M by physically interacting with Alix/AIP1. C protein itself does not have the ability to form VLPs, while M protein provides viral budding force, like other enveloped viruses. Here we show that SeV C protein recruits Alix/AIP1 to the plasma membrane (PM) to facilitate VLP budding. SeV M-VLP budding is sensitive to overexpression of a dominant-negative (DN) form of VPS4A only in the presence of the C proteins, which is able to recruit Alix/AIP1 to the PM. Our results indicate that SeV M and C proteins play separate roles in the budding process: M protein drives budding and C protein enhances the efficiency of the utilization of cellular MVB sorting machinery for efficient VLP budding.     

The conserved carboxyl terminus of human parainfluenza virus type 2 V protein plays an important role in virus growth

Our previous results have shown that some residues of V protein-specific domain in human parainfluenza virus type 2 (hPIV2) are essential not only for STAT protein degradation but also for promoting virus growth. Here, we demonstrated that the virus growth of these recombinant hPIV2s (rPIV2) expressing mutated V proteins were improved in HeLa cell transiently expressing the wild-type V protein, but not in the cells constitutively expressing it. Consequently, we identified the region of the V protein that is essential for its oligomerization and for complex formation with NP protein. We also identified a host protein, AlP1/Alix, involved in apoptosis and efficient budding of several enveloped viruses as an interacting partner of the V and NP proteins. Depletion of AIP1/Alix by small interfering RNA suppressed virus growth. These data suggest that the conserved carboxyl terminus of the V protein plays an important role in virus growth.     

Human macrophages simultaneously express membrane-C1q and Fc-receptors for IgG

Membrane C1q (mC1q) of macrophages (MPhi) is a precursor of the IgG-binding serum protein C1q. Thus, mC1q potentially provides one of several Fcgamma binding sites of mature MPhi and we analyzed whether simultaneous expression occurs of established receptors for IgG, FcgammaRI, II, and III, and mC1q during in vitro differentiation of MPhi. Using flow cytometry, immunoprecipitation combined with Western blotting and Northern blot analysis mC1q was hardly detected in freshly isolated blood monocytes, but increasingly in developing monocyte-derived MPhi. Laser scanning fluorescence microscopy confirmed the membrane localization of mC1q. Two-color-staining flow cytometry experiments indicated that mC1q and all three types of FcgammaRs are simultaneously expressed on mature monocyte-derived MPhi. A high correlation was found for the expression of mC1q and FcgammaRs, in particular FcgammaRII, but not mC1q and CD14, another marker of monocytes/MPhi.     

Distinct subcellular expression of endogenous polycystin-2 in the plasma membrane and Golgi apparatus of MDCK cells.

Polycystin-2 is a predicted integral membrane protein with non-selective cation channel activity. The protein is encoded by the PKD2 gene, which is mutated in approximately 15% of patients with autosomal dominant polycystic kidney disease (ADPKD). Polycystin-2 can interact with the transmembrane protein polycystin-1, the product of the PKD1 gene. However, endoplasmic reticulum (ER) localization was reported for (heterologously expressed) polycystin-2 in cultured cells and baso-lateral localization has been reported in renal tissues. Using two polyclonal antisera raised against polycystin-2 we demonstrated distinct expression of the endogenous protein in the Golgi apparatus and the plasma membrane of MDCK cells. In contrast, most of the heterologously expressed polycystin-2 (PC2-EGFP) remained in the ER, substantially overlapping with the staining pattern of protein-disulfide isomerase (PDI), a marker for the ER. Only in a small subset of these cells weak plasma membrane signals were observed. Membrane staining was also suggested by immunoelectron microscopy and was confirmed by subcellular fractionation on sucrose density gradients. The plasma membrane staining disappeared following extraction with a buffer containing Triton X-100, whereas signals for polycystin-1 and E-cadherin remained visible, suggesting that polycystin-2 is neither tightly bound to the Triton X-100 insoluble cytoskeleton, nor to these proteins. We conclude that endogenous polycystin-2 is transported via the Golgi apparatus to the plasma membrane and has a broader membrane localization than polycystin-1. These data suggest that polycystin-2 can move freely in certain regions of the membrane where it probably functions as a channel, activated by, or in complex with, polycystin-1.     

Ultrastructural Patterns of the Activated Cell Death Programs in the Human Brain

Abstract

The authors analyzed by transmission electron microscopy (TEM) neurosurgical samples obtained from patients with cerebral tumors, neurotrauma, cerebral ischemia, Moyamoya disease, encephalitis, etc. Their observations concern a variety of dying cell types by different programmed death pathways, including apoptosis, paraptosis, autophagy, autoschizis, programmed necrosis, as well as combined and coexisting forms. This ample work pointed out not only the role of TEM in cell death diagnosis, but the biological differences in cell behavior and beneficial or detrimental effects of suicides for homeostasis, survival, or normal functioning of a tissue, like the integrated vascular tissue and brain parenchyma.     

Significance of the YLDL motif in the M protein and Alix/AIP1 for Sendai virus budding in the context of virus infection

Sendai virus (SeV) M protein has a YLDL motif, which is essential for budding of virus-like particles (VLPs) by expression of the M protein. We investigated the importance of the YLDL motif for SeV budding. Virus budding of an M-deficient SeV was not rescued by transient expression of motif mutants, M-A2 (ALDA) and M-A4 (AAAA), and viruses possessing those mutations hardly propagated in cultured cells. However, a budding-competent revertant virus, SeV M-A2R, was obtained from SeV M-A2, and nucleotide sequencing showed an ALDV sequence at the motif instead of the ALDA sequence derived from M-A2. The M-A2R protein rescued budding of an M-deficient SeV, formed VLPs when expressed with viral C protein, and restored the capacity to bind with Alix/AIP1. The results indicate that the YLDL motif is essential for efficient budding in the context of virus infection and suggest involvement of Alix/AIP1 in SeV budding.