技术资料

The peripheral immune system is important in neurodegenerative diseases,both in protecting and inflaming the brain,but the underlying mechanisms remain elusive. Alzheimer’s Disease is commonly preceded by a prodromal period. Here,we report the presence of large Aβ aggregates in plasma from patients with mild cognitive impairment ( n = 38). The aggregates are associated with low level Alzheimer’s Disease-like brain pathology as observed by 11 C-PiB PET and 18 F-FTP PET and lowered CD18-rich monocytes. We characterize complement receptor 4 as a strong binder of amyloids and show Aβ aggregates are preferentially phagocytosed and stimulate lysosomal activity through this receptor in stem cell-derived microglia. KIM127 integrin activation in monocytes promotes size selective phagocytosis of Aβ. Hydrodynamic calculations suggest Aβ aggregates associate with vessel walls of the cortical capillaries. In turn,we hypothesize aggregates may provide an adhesion substrate for recruiting CD18-rich monocytes into the cortex. Our results support a role for complement receptor 4 in regulating amyloid homeostasis. Subject terms: Protein aggregation,Neuroimmunology,Dementia View Publication

In order to further evaluate the parameters whereby intracerebral administration of recombinant α-synuclein (αS) induces pathological phenotypes in mice,we conducted a series of studies where αS fibrils were injected into the brains of M83 (A53T) and M47 (E46K) αS transgenic (Tg) mice,and non-transgenic (nTg) mice. Using multiple markers to assess αS inclusion formation,we find that injected fibrillar human αS induced widespread cerebral αS inclusion formation in the M83 Tg mice,but in both nTg and M47 Tg mice,induced αS inclusion pathology is largely restricted to the site of injection. Furthermore,mouse αS fibrils injected into nTg mice brains also resulted in inclusion pathology restricted to the site of injection with no evidence for spread. We find no compelling evidence for extensive spread of αS pathology within white matter tracts,and we attribute previous reports of white matter tract spreading to cross-reactivity of the αS pSer129/81A antibody with phosphorylated neurofilament subunit L. These studies suggest that,with the exception of the M83 Tg mice which appear to be uniquely susceptible to induction of inclusion pathology by exogenous forms of αS,there are significant barriers in mice to widespread induction of αS pathology following intracerebral administration of amyloidogenic αS. View Publication

Light chain (AL) amyloidosis is a serious systemic disease caused by the deposition of free misfolded immunoglobulin light chains (LCs) in the form of amyloid fibrils within tissues. Cardiac involvement determines prognosis and mortality. An important cytotoxic impact of amyloidogenic prefibrillar LC oligomers on cardiomyocytes is by now established in isolated rodent cardiomyocytes,simple animal models,or cardiomyocyte-like cell lines. However,the response of human cardiomyocytes to this pathogenic condition is currently unknown. In this work,we have set up a human cellular disease model of AL cardiac amyloidosis (AL-CA) in the form of cardiac spheroids,to study the cytotoxic effects of amyloidogenic LCs with regard to contractile function and calcium handling. To mimic the disease in a reconstituted system,soluble amyloidogenic LCs purified from urine of AL-CA patients were added to a mixture of induced pluripotent stem cell-issued human cardiomyocytes (hiPSC-CM) and human primary cardiac fibroblasts,which resulted in formation of spheroids within 7 days. This procedure ensured a uniform pericellular LC distribution within spheroids. LC-treated hiPSC-CM cultures and LC-containing spheroids presented structural and functional defects including: (1) decreased levels and subcellular disorganization of sarcomeric protein alpha-actinin; (2) abnormal accumulation of calcium handling SERCA2a protein; (3) impaired contractility of spheroids and altered calcium transients. Three independent patient-derived LCs had similar effects,albeit to varying degrees,highlighting the patient-specific properties of this type of amyloids. Taken together,these results indicate that the present cardiac spheroid disease model could be appropriate to the study of cardiac cytotoxicity caused by different amyloidogenic LCs in AL-CA patients,contributing to a better understanding and therapeutic handling of the disease. The online version contains supplementary material available at 10.1038/s41598-024-82442-3. View Publication

The ability to yield glucose-responsive pancreatic beta-cells from human pluripotent stem cells in vitro will facilitate the development of the cell replacement therapies for the treatment of Type 1 Diabetes. Here,through the sequential in vitro targeting of selected signaling pathways,we have developed an abbreviated five-stage protocol (25-30 days) to generate human Embryonic Stem Cell-Derived Beta-like Cells (ES-DBCs). We showed that Geltrex,as an extracellular matrix,could support the generation of ES-DBCs more efficiently than that of the previously described culture systems. The activation of FGF and Retinoic Acid along with the inhibition of BMP,SHH and TGF-beta led to the generation of 75% NKX6.1+/NGN3+ Endocrine Progenitors. The inhibition of Notch and tyrosine kinase receptor AXL,and the treatment with Exendin-4 and T3 in the final stage resulted in 35% mono-hormonal insulin positive cells,1% insulin and glucagon positive cells and 30% insulin and NKX6.1 co-expressing cells. Functionally,ES-DBCs were responsive to high glucose in static incubation and perifusion studies,and could secrete insulin in response to successive glucose stimulations. Mitochondrial metabolic flux analyses using Seahorse demonstrated that the ES-DBCs could efficiently metabolize glucose and generate intracellular signals to trigger insulin secretion. In conclusion,targeting selected signaling pathways for 25-30 days was sufficient to generate ES-DBCs in vitro. The ability of ES-DBCs to secrete insulin in response to glucose renders them a promising model for the in vitro screening of drugs,small molecules or genes that may have potential to influence beta-cell function. View Publication

We present a real-time,high-throughput,and cost-effective method of detecting apoptosis in vitro using a previously developed reagent that detects caspase activation by fluorescence. Current methods of assessing apoptosis fail to account for the dimension of time,and thus are limited in data yielded per sample. This reagent allows real-time detection of apoptosis,but until now has been restricted to a costly automated detection system. Here,we describe apoptosis detection with the Essen Bioscience IncuCyte Caspase-3/7 Reagent using a multimode microplate reader,a common instrument in biological laboratories,which may be used prior to or in lieu of the automated system. This modified microplate reader apoptosis assay was validated against the established automated system,and was shown to detect a strong dose-response relationship (automated system r2 = 0.9968,microplate reader r2 = 0.9924). We also propose a quick and reliable method of quantifying cell density by Hoechst 33342 nuclear staining in microplates (r2 = 0.8812 between Hoechst signal and cell density). We assert that the dimension of time should not be overlooked,and that the method presented here is an accessible strategy for many researchers due to low startup cost and precise detection of apoptosis in real time. View Publication

IL-12 is a potent proinflammatory cytokine. The effects of IL-12 are thought to be mediated by IFN-gamma production by NK,NKT,and T cells. In this study,we show that although IL-12 stimulates NK and NK1.1(+) T cells in bulk mouse splenocytes,it does not significantly stimulate purified NK cells,indicating that other cells are required. IL-12 stimulates T cell-deficient spleen cells and those depleted of macrophages. Unexpectedly,the depletion of dendritic cells also has little effect on the stimulation of spleen cells with IL-12. In contrast,B cell depletion almost completely inhibits IL-12-induced IFN-gamma production and B cell-deficient spleen cells are poorly stimulated with IL-12. Furthermore,purified NK cells are stimulated with IL-12 in the presence of purified B cells. Thus,B cells are necessary and also sufficient for the stimulation of purified NK cells with IL-12. Whereas spleen cells from IL-18-deficient mice are not stimulated with IL-12,NK cells purified from IL-18-deficient mice are stimulated with IL-12 in the presence of wild-type (WT) B cells,and WT NK cells are not stimulated with IL-12 in the presence of IL-18-deficient B cells. Cell contact between B and NK cells is also required for IL-12-induced IFN-gamma production. Finally,B cell-deficient mice injected with IL-12 produce significantly less IFN-gamma and IL-18 in the sera than WT mice do. Thus,stimulation of NK cells with IL-12 requires B cell cooperation in vitro as well as in vivo. View Publication

Induced pluripotent stem cell-derived microglia (iMGL) represent an excellent tool in studying microglial function in health and disease. Yet,since differentiation and survival of iMGL are highly reliant on colony-stimulating factor 1 receptor (CSF1R) signaling,it is difficult to use iMGL to study microglial dysfunction associated with pathogenic defects in CSF1R. Serial modifications to an existing iMGL protocol were made,including but not limited to changes in growth factor combination to drive microglial differentiation,until successful derivation of microglia-like cells from an adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) patient carrying a c.2350G > A (p.V784M) CSF1R variant. Using healthy control lines,the quality of the new iMGL protocol was validated through cell yield assessment,measurement of microglia marker expression,transcriptomic comparison to primary microglia,and evaluation of inflammatory and phagocytic activities. Similarly,molecular and functional characterization of the ALSP patient-derived iMGL was carried out in comparison to healthy control iMGL. The newly devised protocol allowed the generation of iMGL with enhanced transcriptomic similarity to cultured primary human microglia and with higher scavenging and inflammatory competence at ~ threefold greater yield compared to the original protocol. Using this protocol,decreased CSF1R autophosphorylation and cell surface expression was observed in iMGL derived from the ALSP patient compared to those derived from healthy controls. Additionally,ALSP patient-derived iMGL presented a migratory defect accompanying a temporal reduction in purinergic receptor P2Y12 ( P2RY12 ) expression,a heightened capacity to internalize myelin,as well as heightened inflammatory response to Pam 3 CSK 4 . Poor P2RY12 expression was confirmed to be a consequence of CSF1R haploinsufficiency,as this feature was also observed following CSF1R knockdown or inhibition in mature control iMGL,and in CSF1R WT/KO and CSF1R WT/E633K iMGL compared to their respective isogenic controls. We optimized a pre-existing iMGL protocol,generating a powerful tool to study microglial involvement in human neurological diseases. Using the optimized protocol,we have generated for the first time iMGL from an ALSP patient carrying a pathogenic CSF1R variant,with preliminary characterization pointing toward functional alterations in migratory,phagocytic and inflammatory activities. The online version contains supplementary material available at 10.1186/s13024-024-00723-x. View Publication

Immunogenicity following an additional dose of Coronavirus disease 2019 (COVID-19) vaccine was investigated in an extended primary series among kidney transplant (KT) recipients. Eighty-five KT participants were randomized to receive either an mRNA (M group; n =??43) or viral vector (V group; n =??42) vaccine. Among them,62% were male,with a median (IQR) age of 50 (43-59) years and post-transplantation duration of 46 (26-82) months. At 2??weeks post-additional dose,there was no difference in the seroconversion rate between the M and V groups (70% vs. 65%,p =??.63). A median (IQR) of anti-RBD antibody level was not statistically different between the M group compared with the V group (51.8 [5.1-591] vs. 28.5 [2.9-119.3] BAU/ml,p =??.18). Furthermore,the percentage of participants with positive SARS-CoV-2 surrogate virus neutralization test results was not statistically different between groups (20% vs. 15%,p =??.40). S1-specific T cell and RBD-specific B cell responses were also comparable between the M and V groups (230 [41-420] vs. 268 [118-510],p =??.65 and 2 [0-10] vs. 2 [0-13] spot-forming units/106 peripheral blood mononuclear cells,p =??.60). In conclusion,compared with an additional dose of viral vector COVID-19 vaccine,a dose of mRNA COVID-19 vaccine did not elicit significantly different responses in KT recipients,regarding either humoral or cell-mediated immunity. (TCTR20211102003). View Publication

Type 1 conventional dendritic cells (cDC1) efficiently cross-present antigens that prime cytotoxic CD8+ T cells. cDC1 therefore constitute conceivable targets in cancer vaccine development. We generated recombinant fusion cancer vaccines that aimed to concomitantly deliver tumor antigen and adjuvant to CD103+ migratory cDC1,following intranasal administration. The fusion vaccine constructs comprised a cDC1-targeting anti-CD103 single chain antibody (aCD103) and a cholera toxin A1 (CTA1) subunit adjuvant,fused with MHC class I and II- or class II-restricted tumor cell antigens to generate a CTA1-I/II-aCD103 vaccine and a CTA1-II-aCD103 vaccine. The immunostimulatory and anti-tumor efficacy of these vaccines was evaluated in murine B16F1-ovalbumin (OVA) melanoma models in C57BL/6 J mice. The CTA1-I/II-aCD103 vaccine was most efficacious and triggered robust tumor antigen-specific CD8+ T cell responses along with a Th17-polarized CD4+ T cell response. This vaccine construct reduced the local growth of implanted B16F1-OVA melanomas and efficiently prevented hematogenous lung metastasis after prophylactic and therapeutic vaccination. Anti-tumor effects of the CTA1-I/II-aCD103 vaccine were antigen-specific and long-lasting. These results imply that adjuvant-containing recombinant fusion vaccines that target and activate cDC1 trigger effective anti-tumor immunity to control tumor growth and metastasis. View Publication

Focal malformations of cortical development (FMCDs) account for the majority of drug-resistant pediatric epilepsy. Postzygotic somatic mutations activating the phosphatidylinositol-4,5-bisphosphate-3-kinase (PI3K)-protein kinase B (AKT)-mammalian target of rapamycin (mTOR) pathway are found in a wide range of brain diseases,including FMCDs. It remains unclear how a mutation in a small fraction of cells disrupts the architecture of the entire hemisphere. Within human FMCD-affected brain,we found that cells showing activation of the PI3K-AKT-mTOR pathway were enriched for the AKT3(E17K) mutation. Introducing the FMCD-causing mutation into mouse brain resulted in electrographic seizures and impaired hemispheric architecture. Mutation-expressing neural progenitors showed misexpression of reelin,which led to a non-cell autonomous migration defect in neighboring cells,due at least in part to derepression of reelin transcription in a manner dependent on the forkhead box (FOX) transcription factor FOXG1. Treatments aimed at either blocking downstream AKT signaling or inactivating reelin restored migration. These findings suggest a central AKT-FOXG1-reelin signaling pathway in FMCD and support pathway inhibitors as potential treatments or therapies for some forms of focal epilepsy. View Publication

MALT1 paracaspase is central for lymphocyte antigen-dependent responses including NF-kappaB activation. We discovered nanomolar,selective allosteric inhibitors of MALT1 that bind by displacing the side chain of Trp580,locking the protease in an inactive conformation. Interestingly,we had previously identified a patient homozygous for a MALT1 Trp580-to-serine mutation who suffered from combined immunodeficiency. We show that the loss of tryptophan weakened interactions between the paracaspase and C-terminal immunoglobulin MALT1 domains resulting in protein instability,reduced protein levels and functions. Upon binding of allosteric inhibitors of increasing potency,we found proportionate increased stabilization of MALT1-W580S to reach that of wild-type MALT1. With restored levels of stable MALT1 protein,the most potent of the allosteric inhibitors rescued NF-kappaB and JNK signaling in patient lymphocytes. Following compound washout,MALT1 substrate cleavage was partly recovered. Thus,a molecular corrector rescues an enzyme deficiency by substituting for the mutated residue,inspiring new potential precision therapies to increase mutant enzyme activity in other deficiencies. View Publication

Establishment of angiogenic circuits that orchestrate blood vessel development and remodeling requires an exquisite balance between the activities of pro- and antiangiogenic factors. However,the logic that permits complex signal integration by vascular endothelium is poorly understood. We demonstrate that a neuropeptide� View Publication