A T-cell antigen atlas for meningioma: novel options for immunotherapy

脑膜瘤T细胞抗原图谱：免疫治疗的新选择

Meningiomas are the most common primary intracranial tumors. Although most symptomatic cases can be managed by surgery and/or radiotherapy, a relevant number of patients experience an unfavorable clinical course and additional treatment options are needed. As meningiomas are often perfused by dural branches of the external carotid artery, which is located outside the blood-brain barrier, they might be an accessible target for immunotherapy. However, the landscape of naturally presented tumor antigens in meningioma is unknown. We here provide a T-cell antigen atlas for meningioma by in-depth profiling of the naturally presented immunopeptidome using LC-MS/MS. Candidate target antigens were selected based on a comparative approach using an extensive immunopeptidome data set of normal tissues. Meningioma-exclusive antigens for HLA class I and II are described here for the first time. Top-ranking targets were further functionally characterized by showing their immunogenicity through in vitro T-cell priming assays. Thus, we provide an atlas of meningioma T-cell antigens which will be publicly available for further research. In addition, we have identified novel actionable targets that warrant further investigation as an immunotherapy option for meningioma.

脑膜瘤是最常见的颅内原发肿瘤。虽然大多数有症状的病例可以通过手术和/或放射治疗来处理，但也有相当数量的患者经历了不利的临床过程，需要额外的治疗选择。由于脑膜瘤通常由位于血脑屏障外的颈外动脉的硬膜支灌流，因此脑膜瘤可能是免疫治疗的靶点。然而，脑膜瘤中自然呈现的肿瘤抗原的情况尚不清楚。在这里，我们提供了脑膜瘤的T细胞抗原图谱，通过使用LC-MS/MS对自然呈现的免疫肽进行深入的剖析，基于使用广泛的正常组织的免疫肽数据集的比较方法来选择候选靶抗原。脑膜瘤专属抗原的人类白细胞抗原I和II是第一次在这里描述。通过体外T细胞启动试验显示其免疫原性，进一步对顶级靶标进行了功能鉴定。因此，我们提供了脑膜瘤T细胞抗原的图谱，该图谱将公开可供进一步研究。此外，我们已经确定了新的可操作的靶点，值得进一步研究作为脑膜瘤的免疫治疗选择。

REF: Medici G, Freudenmann LK, Velz J, et al. A T-cell antigen atlas for meningioma: novel options for immunotherapy. Acta Neuropathol. 2023;146(2):173-190. doi:10.1007/s00401-023-02605-w PMID: 37368072 PMCID: PMC10329067

Tau seeding and spreading in vivo is supported by both AD-derived fibrillar and oligomeric tau

Tau在体内的播种和扩散受到AD来源的纤维和寡聚体tau的支持

Insoluble fibrillar tau, the primary constituent of neurofibrillary tangles, has traditionally been thought to be the biologically active, toxic form of tau mediating neurodegeneration in Alzheimer's disease. More recent studies have implicated soluble oligomeric tau species, referred to as high molecular weight (HMW) due to its properties on size exclusion chromatography, in tau propagation across neural systems. These two forms of tau have never been directly compared. We prepared sarkosyl insoluble and HMW tau from the frontal cortex of Alzheimer patients and compared their properties using a variety of biophysical and bioactivity assays. Sarkosyl insoluble fibrillar tau is comprised of abundant paired helical filaments (PHF) as quantified by electron microscopy (EM), and is more resistant to proteinase K, compared to HMW tau which is mostly in an oligomeric form. Sarkosyl insoluble and HMW tau are nearly equivalent in potency in a HEK cell bioactivity assay for seeding aggregates and their injection reveals similar local uptake into hippocampal neurons in PS19 Tau transgenic mice. However, the HMW preparation appears to be far more potent in inducing a glial response including Clec7a-positive rod-microglia in the absence of neurodegeneration or synapse loss and promotes more rapid propagation of misfolded tau to distal, anatomically connected regions, such as entorhinal and perirhinal cortices. These data suggest that soluble HMW tau has similar properties to fibrillar sarkosyl insoluble tau with regard to tau seeding potential but may be equal or even more bioactive with respect to propagation across neural systems and activation of glial responses, both relevant tau-related Alzheimer phenotypes.

不溶性纤维tau是神经纤维缠结的主要成分，传统上被认为是具有生物活性的有毒形式的tau，介导阿尔茨海默病的神经退化。最近的研究表明，可溶性低聚tau物种，由于其在尺寸排除层析上的性质而被称为高分子量(HMW)，与tau在神经系统中的繁殖有关。这两种形式的tau从未被直接比较过。我们从阿尔茨海默病患者的额叶皮质制备了肌糖不溶性和HMW tau，并使用各种生物物理和生物活性分析比较了它们的性质。根据电子显微镜(EM)的定量，Sarkosyl不溶性纤维tau由大量成对的螺旋细丝(PHF)组成，并且与HMW tau相比，Sarkosyl不溶性tau对蛋白酶K更具抵抗力，HMW tau主要以低聚形式存在。在HEK细胞生物活性测定中，Sarkosyl Unsolble和HMW tau在种子聚集体的HEK细胞生物活性测定中的效力几乎相同，它们的注射在PS19 Tau转基因小鼠的海马神经元中显示出类似的局部摄取。然而，在没有神经变性或突触丢失的情况下，HMW制剂似乎在诱导包括Clec7a阳性的视杆小胶质细胞在内的胶质反应方面要有效得多，并促进错误折叠的tau更快地传播到远端解剖连接的区域，如内嗅觉和虹膜周围皮质。这些数据表明，在tau的播种潜力方面，可溶性的HMW tau与纤维状的肌糖不溶性tau具有相似的性质，但在跨神经系统传播和激活神经胶质反应方面可能具有相同的甚至更高的生物活性，这两种都是tau相关的阿尔茨海默病表型。

REF: Mate De Gerando A, Welikovitch LA, Khasnavis A, et al. Tau seeding and spreading in vivo is supported by both AD-derived fibrillar and oligomeric tau. Acta Neuropathol. 2023;146(2):191-210. doi:10.1007/s00401-023-02600-1 PMID: 37341831 PMCID: PMC10329061

Mutation ∆K281 in MAPT causes Pick’s disease

MAPT基因突变∆K281导致皮克氏病

Two siblings with deletion mutation ∆K281 in MAPT developed frontotemporal dementia. At autopsy, numerous inclusions of hyperphosphorylated 3R Tau were present in neurons and glial cells of neocortex and some subcortical regions, including hippocampus, caudate/putamen and globus pallidus. The inclusions were argyrophilic with Bodian silver, but not with Gallyas-Braak silver. They were not labelled by an antibody specific for tau phosphorylated at S262 and/or S356. The inclusions were stained by luminescent conjugated oligothiophene HS-84, but not by bTVBT4. Electron cryo-microscopy revealed that the core of tau filaments was made of residues K254-F378 of 3R Tau and was indistinguishable from that of Pick's disease. We conclude that MAPT mutation ∆K281 causes Pick's disease.

两名携带∆K281缺失突变的兄弟姐妹患上额颞叶痴呆。在尸检中，新皮质的神经元和胶质细胞以及一些皮质下区域，包括海马区、尾壳核和苍白球，可见大量过度磷酸化的3R Tau包涵体。包裹体与Bodian银亲银，但与Galyas-Braak银不亲银。它们没有被在S262和/或S356磷酸化的tau特异性抗体标记。荧光共轭低聚硫酚HS-84可使包裹体显色，而bTVBT4不显色。电子冷冻显微镜显示，tau丝的核心是由3R Tau的K254-F378残基组成的，与Pick病的核心没有区别。我们认为MAPT突变∆K281导致Pick‘s病。

REF: Schweighauser M, Garringer HJ, Klingstedt T, et al. Mutation ∆K281 in MAPT causes Pick's disease. Acta Neuropathol. 2023;146(2):211-226. doi:10.1007/s00401-023-02598-6 PMID: 37351604 PMCID: PMC10329087

Transcriptomic profiling of Parkinson's disease brains reveals disease stage specific gene expression changes

帕金森病脑的转录图谱揭示疾病阶段特异性基因表达的变化

Parkinson´s disease (PD) is a progressive neurodegenerative disorder characterized by both motor and non-motor symptoms. Aggravation of symptoms is mirrored by accumulation of protein aggregates mainly composed by alpha-synuclein in different brain regions, called Lewy bodies (LB). Previous studies have identified several molecular mechanisms as autophagy and inflammation playing a role in PD pathogenesis. Increased insights into mechanisms involved in early disease stages and driving the progression of the LB pathology are required for the development of disease-modifying strategies. Here, we aimed to elucidate disease stage-specific transcriptomic changes in brain tissue of well-characterized PD and control donors. Together our results indicate that transcriptomic dysregulation and associated functional changes are highly disease stage-specific, which has major implications for the study of neurodegenerative disorders.

帕金森S病(PD)是一种进行性神经退行性疾病，以运动和非运动症状为特征。症状的加重反映为主要由α-突触核蛋白组成的蛋白质聚集体在不同的大脑区域积累，称为路易小体(Lb)。先前的研究已经确定了自噬和炎症在帕金森病发病机制中发挥作用的几个分子机制。对于疾病修正策略的发展，需要对早期疾病阶段涉及的机制和推动LB型病理学进展的机制有更深入的了解。在这里，我们的目标是阐明帕金森病患者和对照供者脑组织中疾病阶段特异性转录改变。综上所述，我们的结果表明，转录调控失调和相关的功能变化是高度疾病阶段特异性的，这对神经退行性疾病的研究具有重要意义。

REF: Cappelletti C, Henriksen SP, Geut H, et al. Transcriptomic profiling of Parkinson's disease brains reveals disease stage specific gene expression changes. Acta Neuropathol. 2023;146(2):227-244. doi:10.1007/s00401-023-02597-7 PMID: 37347276 PMCID: PMC10329075

Mutant LRRK2 exacerbates immune response and neurodegeneration in a chronic model of experimental colitis

突变型LRRK2加重实验性结肠炎慢性模型的免疫反应和神经变性

The link between the gut and the brain in Parkinson's disease (PD) pathogenesis is currently a subject of intense research. Indeed, gastrointestinal dysfunction is known as an early symptom in PD and inflammatory bowel disease (IBD) has recently been recognised as a risk factor for PD. The leucine-rich repeat kinase 2 (LRRK2) is a PD- and IBD-related protein with highest expression in immune cells. In this study, we provide evidence for a central role of LRRK2 in gut inflammation and PD. Taken together, our results link LRRK2 with the immune response in colitis and provide evidence that gut inflammation can impact brain homeostasis and contribute to neurodegeneration in PD.

帕金森氏病(PD)发病机制中肠道和大脑之间的联系目前是一个密集的研究主题。事实上，胃肠功能障碍被认为是帕金森病的早期症状，炎症性肠病(IBD)最近被认为是帕金森病的危险因素。富含亮氨酸的重复蛋白2(LRRK2)是PD和IBD相关蛋白，在免疫细胞中表达水平最高。在这项研究中，我们提供了LRRK2在肠道炎症和帕金森病中发挥核心作用的证据。综上所述，我们的结果将LRRK2与结肠炎的免疫反应联系起来，并提供了肠道炎症可以影响大脑稳态并导致帕金森病神经变性的证据。

REF: Cabezudo D, Tsafaras G, Van Acker E, Van den Haute C, Baekelandt V. Mutant LRRK2 exacerbates immune response and neurodegeneration in a chronic model of experimental colitis. Acta Neuropathol. 2023;146(2):245-261. doi:10.1007/s00401-023-02595-9 PMID: 37289222 PMCID: PMC10328902

Central and peripheral myeloid-derived suppressor cell-like cells are closely related to the clinical severity of multiple sclerosis

中枢和外周髓系来源的抑制性细胞样细胞与多发性硬化的临床严重程度密切相关

Multiple sclerosis (MS) is a highly heterogeneous demyelinating disease of the central nervous system (CNS) that needs for reliable biomarkers to foresee disease severity. Recently, myeloid-derived suppressor cells (MDSCs) have emerged as an immune cell population with an important role in MS. The monocytic-MDSCs (M-MDSCs) share the phenotype with Ly-6Chi-cells in the MS animal model, experimental autoimmune encephalomyelitis (EAE), and have been retrospectively related to the severity of the clinical course in the EAE. However, no data are available about the presence of M-MDSCs in the CNS of MS patients or its relation with the future disease aggressiveness. In this work, we show for the first time cells exhibiting all the bona-fide phenotypical markers of M-MDSCs associated with MS lesions, whose abundance in these areas appears to be directly correlated with longer disease duration in primary progressive MS patients. In summary, our data point to M-MDSC load as a factor to be considered for future studies focused on the prediction of disease severity in EAE and MS.

多发性硬化症(MS)是一种高度异质性的中枢神经系统脱髓鞘疾病，需要可靠的生物标志物来预测疾病的严重程度。近年来，髓系细胞来源的抑制细胞(MDSCs)作为一种免疫细胞群在MS发病中起着重要作用，在MS动物模型实验性自身免疫性脑脊髓炎(EAE)中，单核细胞MDSCs(M-MDSCs)与Ly-6CHI细胞具有相同的表型，并与EAE的临床病程严重程度密切相关。然而，没有关于MS患者中枢神经系统中M-MDSCs的存在及其与未来疾病侵袭性的关系的数据。在这项工作中，我们首次展示了与MS病变相关的M-MDSCs的所有真正表型标记，其在这些区域的丰度似乎与原发进展性MS患者较长的病程直接相关。总之，我们的数据指出，M-MDSC负荷是未来专注于预测EAE和MS疾病严重程度的研究需要考虑的一个因素。

REF: Ortega MC, Lebrón-Galán R, Machín-Díaz I, et al. Central and peripheral myeloid-derived suppressor cell-like cells are closely related to the clinical severity of multiple sclerosis. Acta Neuropathol. 2023;146(2):263-282. doi:10.1007/s00401-023-02593-x PMID: 37243699 PMCID: PMC10329064

From methylation to myelination: epigenomic and transcriptomic profiling of chronic inactive demyelinated multiple sclerosis lesions

从甲基化到髓鞘形成：慢性非活动性脱髓鞘多发性硬化症病变的表观基因组和转录图谱

In the progressive phase of multiple sclerosis (MS), the hampered differentiation capacity of oligodendrocyte precursor cells (OPCs) eventually results in remyelination failure. We have previously shown that DNA methylation of Id2/Id4 is highly involved in OPC differentiation and remyelination. In this study, we took an unbiased approach by determining genome-wide DNA methylation patterns within chronically demyelinated MS lesions and investigated how certain epigenetic signatures relate to OPC differentiation capacity. Our data indicate that OPCs within chronically demyelinated MS lesions acquire an inhibitory phenotype, which translates into hypermethylation of crucial myelination-related genes. Altering the epigenetic status of MBP can restore the differentiation capacity of OPCs and possibly boost (re)myelination.

在多发性硬化症(MS)的进展期，少突胶质前体细胞(OPC)的分化能力受阻，最终导致再髓鞘失败。我们先前已经证明，Id2/Id4的DNA甲基化与OPC的分化和重新髓鞘形成密切相关。在这项研究中，我们采取了一种公正的方法，在慢性脱髓鞘的MS病变中确定了全基因组DNA甲基化模式，并调查了某些表观遗传特征与OPC分化能力的关系。我们的数据表明，慢性脱髓鞘MS病变中的OPC获得了一种抑制表型，这转化为关键的髓鞘形成相关基因的高甲基化。改变MBP的表观遗传状态可以恢复OPC的分化能力，并可能促进(重新)髓鞘形成。

REF: Tiane A, Schepers M, Reijnders RA, et al. From methylation to myelination: epigenomic and transcriptomic profiling of chronic inactive demyelinated multiple sclerosis lesions. Acta Neuropathol. 2023;146(2):283-299. doi:10.1007/s00401-023-02596-8 PMID: 37286732 PMCID: PMC10328906

Defective cerebellar ryanodine receptor type 1 and endoplasmic reticulum calcium ‘leak’ in tremor pathophysiology

震颤病理生理学中小脑Ryanodine受体1型缺陷和内质网钙“泄漏”

Essential Tremor (ET) is a prevalent neurological disease characterized by an 8-10 Hz action tremor. Molecular mechanisms of ET remain poorly understood. Clinical data suggest the importance of the cerebellum in disease pathophysiology, and pathological studies indicate Purkinje Cells (PCs) incur damage. Our recent cerebellar cortex and PC-specific transcriptome studies identified alterations in calcium (Ca2+) signaling pathways that included ryanodine receptor type 1 (RyR1) in ET. RyR1 is an intracellular Ca2+release channel located on the Endoplasmic Reticulum (ER), and in cerebellum is predominantly expressed in PCs. Under stress conditions, RyR1 undergoes several post-translational modifications (protein kinase A [PKA] phosphorylation, oxidation, nitrosylation), coupled with depletion of the channel-stabilizing binding partner calstabin1, which collectively characterize a "leaky channel" biochemical signature. In this study, we found markedly increased PKA phosphorylation at the RyR1-S2844 site, increased RyR1 oxidation and nitrosylation, and calstabin1 depletion from the RyR1 complex in postmortem ET cerebellum. The data collectively support that stress-associated ER Ca2+leak via RyR1 may contribute to tremor pathophysiology.

原发性震颤(Essential Tremor，ET)是一种以8-10赫兹动作震颤为特征的神经系统疾病。ET的分子机制仍知之甚少。临床数据表明小脑在疾病病理生理学中的重要性，病理研究表明浦肯野细胞(PC)受到损害。我们最近的小脑皮质和PC特异性转录组研究发现，包括ET中Ryanodine受体1(RyR1)在内的钙(Ca+)信号通路发生了变化。RyR1是一种位于内质网(ER)的细胞内钙释放通道，在小脑中主要表达于PC。在应激条件下，RyR1经历了几次翻译后修饰(蛋白激酶A[PKA]的磷酸化、氧化、亚硝化)，加上稳定通道的结合伙伴calstain1的耗尽，这些共同表征了“泄漏通道”的生化特征。在这项研究中，我们发现在死后的小脑中，RyR1-S2844位点的PKA磷酸化显著增加，RyR1的氧化和亚硝化作用增加，RyR1复合体中的Calstain1被耗尽。这些数据共同支持，通过RyR1的应激相关的内质网钙离子泄漏可能有助于震颤的病理生理学。

REF: Martuscello RT, Chen ML, Reiken S, et al. Defective cerebellar ryanodine receptor type 1 and endoplasmic reticulum calcium 'leak' in tremor pathophysiology. Acta Neuropathol. 2023;146(2):301-318. doi:10.1007/s00401-023-02602-z PMID: 37335342 PMCID: PMC10350926

Individual myasthenia gravis autoantibody clones can efficiently mediate multiple mechanisms of pathology

单个重症肌无力自身抗体克隆可有效地介导多种病理机制

Serum autoantibodies targeting the nicotinic acetylcholine receptor (AChR) in patients with autoimmune myasthenia gravis (MG) can mediate pathology via three distinct molecular mechanisms: complement activation, receptor blockade, and antigenic modulation. However, it is unclear whether multi-pathogenicity is mediated by individual or multiple autoantibody clones. Using an unbiased B cell culture screening approach, we generated a library of 11 human-derived AChR-specific recombinant monoclonal autoantibodies (mAb) and assessed their binding properties and pathogenic profiles using specialized cell-based assays. The findings provide new insight into the immunopathology of MG, demonstrating that single autoreactive clones can efficiently mediate multiple modes of pathology. Current therapeutic approaches targeting only one autoantibody-mediated pathogenic mechanism may be evaded by autoantibodies with multifaceted capacity.

自身免疫性重症肌无力(MG)患者血清中针对烟碱型乙酰胆碱受体(AChR)的自身抗体可通过三种不同的分子机制介导病理改变：补体激活、受体阻断和抗原调节。然而，目前尚不清楚多致病性是由单个自身抗体克隆还是多个自身抗体克隆介导的。使用无偏倚的B细胞培养筛选方法，我们建立了11个人源性AChR特异性重组单抗(MAb)的文库，并使用专门的基于细胞的分析方法评估了它们的结合特性和病原学特征。这一发现为MG的免疫病理机制提供了新的见解，表明单个自身反应克隆可以有效地介导多种病理模式。目前仅针对一种自身抗体介导的致病机制的治疗方法可能会被具有多方面能力的自身抗体所回避。

REF: Pham MC, Masi G, Patzina R, et al. Individual myasthenia gravis autoantibody clones can efficiently mediate multiple mechanisms of pathology. Acta Neuropathol. 2023;146(2):319-336. doi:10.1007/s00401-023-02603-y PMID: 37344701