Novel CSF biomarkers for diagnosis and integrated analysis of neuropsychiatric systemic lupus erythematosus: based on antibody profiling.

BACKGROUND: Neuropsychiatric systemic lupus erythematosus (NPSLE), with various morbidities and multiple manifestations in the central nervous system, remains a limited standard for diagnosis. Our study was to discover novel biomarkers for improving the diagnostic efficiency for NPSLE. METHODS: We performed a quantitative planar protein antibody microarray to screen 1000 proteins in cerebrospinal fluid from controls, systemic lupus erythematosus (SLE, non-NPSLE) patients, and NPSLE patients. Differentially expressed proteins (DEPs) as candidate biomarkers were developed into a custom multiplexed protein antibody array for further validation in an independent larger cohort. Subsequently, we used least absolute shrinkage and selection operator regression (LASSO) analysis and multivariable logistic regression analysis for optimizing feature selection and constructing a diagnostic model. A receiver operating characteristic curve (ROC) was generated to assess the effectiveness of the models. RESULTS: The expression of 29 proteins in CSF was significantly altered in the comparison of the three groups. We selected 17 proteins as candidate biomarkers in accordance with protein interaction analysis. In the larger cohort, we identified 5 DEPs as biomarkers for NPSLE, including TCN2, CST6, KLK5, L-selectin, and Trappin-2. The diagnostic model included 3 hub proteins (CST6, TCN2, KLK5) and was best at discriminating NPSLE from SLE patients. These CSF biomarkers were also highly associated with disease activity. In addition, there were 6 molecules with remarkable changes in NPSLE CSF and hippocampus, which indicated the consistency of the environment in the brain and the promising molecular targets in the pathogenesis of NPSLE. CONCLUSIONS: The dual-chips screening strategy demonstrated KLK5, L-selectin, Trappin-2, TCN2, and CST6 as CSF biomarkers for diagnosing NPSLE.

Systemic administration of Shikonin ameliorates cognitive impairment and neuron damage in NPSLE mice.

Shikonin is an anti-inflammatory natural herbal drug extracted from Lithospermum erythrorhizon and its therapeutic effect on neuropsychiatric systemic lupus erythematosus (NPSLE) is yet unknown. In our study, Shikonin significantly reversed the cognitive impairment and alleviated the brain tissue damage in NPSLE mice. The permeability of blood-brain barrier was also verified to be repaired in Shikonin-treated NPSLE mice. In particular, we found that Shikonin alleviated neuroinflammation through inhibiting ß-catenin signaling pathway, thereby depressing the activation of microglia and the loss of neuronal synapses. Overall, Shikonin may be a promising candidate drug for NPSLE through diminishing neuroinflammation and repairing neuron damage.

Halofuginone ameliorates systemic lupus erythematosus by targeting Blk in myeloid-derived suppressor cells.

Systemic lupus erythematosus (SLE) is a multisystemic, inflammatory autoimmune disease. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells participated in the pathogenesis of SLE. MDSCs has been considered a potential therapeutic target for lupus. As traditional Chinese medicine, Halofuginone (HF) has the extensive immunomodulatory effects on some autoimmune disorders. Our research was dedicated to discovering therapeutic efficacy of HF for lupus to explore novel mechanisms on MDSCs. We found that HF prominently alleviated the systemic symptoms especially nephritis in Imiquimod-induced lupus mice, and simultaneously repaired the immune system, reflected in the alteration of autoantibodies. HF diminished the quantity of MDSCs in lupus mice, and induced apoptosis of MDSCs. Through RNA sequencing performed on the sorted MDSC from lupus mice and HF-treated lupus mice, B lymphoid tyrosine kinase (Blk, a non-receptor cytoplasmic tyrosine kinase) was screened as the target molecule of HF. It's proven that HF had two independent effects on Blk. On the one hand, HF increased the mRNA expression of Blk in MDSCs by inhibiting the nuclear translocation of p65/p50 heterodimer. On the other hand, HF enhanced the kinase activity of Blk in MDSCs through direct molecular binding. We further investigated that Blk suppressed the phosphorylation of downstream ERK signaling pathway to increase the apoptosis of MDSCs. In conclusion, our study illustrated that HF alleviated the disease progression of lupus mice by targeting Blk to promote the apoptosis of MDSCs, which indicated the immunotherapeutic potential of HF to treat lupus.

Small molecule compound K-7174 attenuates neuropsychiatric manifestations in lupus-prone mice.

The neuropsychiatric manifestations of systemic lupus erythematosus (NPSLE) present significant morbidity and mortality due to frequent non-response or adverse effects of the current clinical drugs. The disruption of the blood-brain barrier (BBB) contributes to inflammatory NPSLE disease progression. K-7174, a highly piperazine-derived compound, inhibits leukocyte adhesion and inflammatory factor expression. The present study aimed to comprehensively assess the treatment effect of neurobehavioral deficits in MRL/lpr mice, a validated neuropsychiatric lupus model. The intraperitoneal injection of K-7174 alleviated lupus-like symptoms and improved cognitive dysfunction in MRL/lpr mice. Also, it significantly attenuated neuronal degeneration and decreased serum albumin deposition in the hippocampus. Furthermore, K-7174 acted directly on the brain microvascular endothelial bEnd.3 cells and reduced the BBB permeability, manifested by inhibiting the activation of brain microvascular endothelial cells and increasing the expression of tight junctions (TJs). Notably, in vitro experiments showed that K-7174 alleviates the decreased ZO1 and Occludin expression in bEnd.3 cells caused by lactate increase, improving cell permeability via the MCT4/NKAP/CREB signaling pathway. These findings suggested that K-7174 mediates the attenuation of NPSLE in MRL/lpr mice, indicating a promising therapeutic strategy for NPSLE.

A hybrid metal-organic framework nanomedicine-mediated photodynamic therapy and hypoxia-activated cancer chemotherapy.

The hypoxic tumor microenvironment and photodynamic therapy (PDT)-aggravated hypoxia compromise the anticancer efficacy of chemotherapy, immunotherapy, and PDT. Thus, sophisticated nanomedicines that can activate their anticancer capability in situ in response to specific stimuli need to be developed. This study aimed to construct a hybrid nanomedicine that activated chemotherapy by inducing hypoxia, which synergized with PDT to promote antitumor outcomes, contrary to the strategies focusing on reversing tumor hypoxia. The hybridization of a porphyrin metal-organic framework (MOF) and gold nanoparticles (AuNPs) enhanced the stability of the hybrid nanomedicine against the phosphate in blood, thereby preventing the premature drug release during blood circulation. The surface modification with polyethylene glycol (PEG) markedly increased the tumor accumulation of the hybrid MOF nanomedicine, which encapsulated a hypoxia-activated prodrug (tirapazamine, TPZ), by enhancing its colloidal stability and pharmacokinetics. The loaded TPZ was rapidly released from the nanomedicine in response to the concentrated intracellular phosphate after cellular uptake, and was then converted into a potent anticancer drug in a hypoxic microenvironment exacerbated by continuous O2 consumption during PDT. In vitro and in vivo experiments demonstrated that the synergistic PDT and hypoxia-activated chemotherapy exhibited enhanced antitumor therapeutic efficiency and superior antimetastatic effect, and effectively ablated the tumor without recurrence. Therefore, the sophisticated nanomedicine reported here, which eliminated cancer cells by inducing a hypoxic tumor microenvironment, showed translational potential in future therapeutic development.

Hydroxychloroquine induces apoptosis of myeloid-derived suppressor cells via up-regulation of CD81 contributing to alleviate lupus symptoms.

BACKGROUND: Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that results from widespread immune complex deposition and secondary tissue injury. Hydroxychloroquine (HCQ) has been used clinically to treat SLE, while its exact mechanism has still remained elusive. Some studies have shown that myeloid-derived suppressor cells (MDSCs) play a vital role in the regulation of SLE. In this study, we aimed to explore the effects of HCQ on the apoptosis of MDSCs in lupus mice and its possible molecular regulatory mechanism. METHODS: We constructed the imiquimod (IMQ)-induced lupus model in mice. The proportion and apoptosis of MDSCs were measured by flow cytometry. CD81-overexpressed adeno-associated virus was intraperitoneally injected into the lupus mice. We also transfected the CD81 siRNA into bone marrow-derived MDSCs, and employed qRT-PCR and Western blotting to quantify the level of CD81. RESULTS: The results showed that HCQ ameliorated IMQ-induced lupus symptoms, and simultaneously inhibited the expansion of MDSCs. In particular, HCQ induced the apoptosis of MDSCs, and also up-regulated the expression level of CD81 in MDSCs, which might indicate the relationship between the expression level of CD81 and the apoptosis of MDSCs. CD81 was further confirmed to participate in the apoptosis of MDSCs and lupus disease progression by overexpressing CD81 in vivo. Molecular docking experiment further proved the targeting effect of HCQ on CD81. And then we interfered CD81 in bone marrow derived MDSCs in vitro, and it was revealed that HCQ rescued the decreased expression level of CD81 and relieved the immune imbalance of Th17/Treg cells. CONCLUSION: In summary, HCQ promoted the apoptosis of MDSCs by up-regulating the expression level of CD81 in MDSCs, and ultimately alleviated lupus symptoms. Our results may assist scholars to develop further effective therapies for SLE.

The correlation between proteoglycan 2 and neuropsychiatric systemic lupus erythematosus.

The proposed pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) mainly includes ischemia and neuroinflammation mechanisms. Protein encoded by Proteoglycan 2 (PRG2) mRNA is involved in the immune process related to eosinophils, also being found in the placenta and peripheral blood of pregnant women. We evaluated the correlation between PRG2 and NPSLE for the first time and found that PRG2 protein was overexpressed in the serum of patients with NPSLE and correlated with the SLE disease activity index (SLEDAI) subset scores of psychosis. Moreover, we investigated the correlation between hippocampal PRG2 level and hippocampally dependent learning and memory ability in MRL/lpr mice, and discovered that the number of PRG2+GFAP+ astrocytes in the cortex and hypothalamus and the number of PRG2+IBA-1+ microglia in the hippocampus and cortex significantly increased in the MRL/lpr mice. These data provided a reference for the follow-up exploration of the role of PRG2 in SLE or other diseases.

Pyruvate kinase isoform M2 impairs cognition in systemic lupus erythematosus by promoting microglial synaptic pruning via the ß-catenin signaling pathway.

BACKGROUND: Neuropsychiatric systemic lupus erythematosus (NPSLE) is a severe complication, which involves pathological damage to the brain and cognitive function. However, its exact mechanism of action still remains unclear. In this study, we explored the role of microglia in the cognitive dysfunction of NPSLE mice. We also analyzed and compared the metabolites in the hippocampal tissues of the lupus model and control mice. METHODS: MRL/MpJ-Faslpr (MRL/lpr) female mice were used as the NPSLE mouse model. Metabolomics was used to assess hippocampal glycolysis levels. Glucose, lactic acid, IL-6, and IL-1ß of the hippocampus were detected by ELISA. Based on the glycolysis pathway, we found that pyruvate kinase isoform M2 (PKM2) in the hippocampus was significantly increased. Thus, the expression of PKM2 was detected by qRT-PCR and Western blotting, and the localization of PKM2 in microglia (IBA-1+) or neurons (NeuN+) was assessed by immunofluorescence staining. Flow cytometry was used to detect the number and phenotype of microglia; the changes in microglial phagocytosis and the ß-catenin signaling pathway were detected in BV2 cells overexpressing PKM2. For in vivo experiments, MRL/lpr mice were treated with AAV9-shPKM2. After 2 months, Morris water maze and conditional fear tests were applied to investigate the cognitive ability of mice; H&E and immunofluorescence staining were used to evaluate brain damage; flow cytometry was used to detect the phenotype and function of microglia; neuronal synapse damage was monitored by qRT-PCR, Western blotting, and immunofluorescence staining. RESULTS: Glycolysis was elevated in the hippocampus of MRL/lpr lupus mice, accompanied by increased glucose consumption and lactate production. Furthermore, the activation of PKM2 in hippocampal microglia was observed in lupus mice. Cell experiments showed that PKM2 facilitated microglial activation and over-activated microglial phagocytosis via the ß-catenin signaling pathway. In vivo, AAV9-shPKM2-treated mice showed decreased microglial activation and reduced neuronal synapses loss by blocking the ß-catenin signaling pathway. Furthermore, the cognitive impairment and brain damage of MRL/lpr mice were significantly relieved after microglial PKM2 inhibition. CONCLUSION: These data indicate that microglial PKM2 have potential to become a novel therapeutic target for treating lupus encephalopathy.

MAGI2-AS3 inhibits breast cancer by downregulating DNA methylation of MAGI2.

Breast cancer is one of the most threatening diseases for women. Long noncoding RNAs were reported to be involved in breast cancer development. In this study, we analyzed The Cancer Genome Atlas breast cancer tissue high-throughput sequencing data and screened and validated the low-expressing long noncoding RNA named MAGI2-AS3. Through gene coexpression analysis, we found that MAGI2-AS3 has a good expression correlation with MAGI2. Overexpression of MAGI2-AS3 or MAGI2 in breast cancer cells MCF-7 would inhibit the Wnt/ß-catenin pathway and inhibit cell proliferation and migration. Gene structure and DNA methylation analysis results indicated that MAGI2-AS3 may act as a cis-acting regulatory element downregulating the DNA methylation level of the MAGI2 promoter region, and the DNA demethylase TET1 inhibitor can reverse MAGI2-AS3 overexpression caused upregulation of MAGI2 and cellular effects. Our findings reveal the role of MAGI2-AS3 in breast cancer and provide potential novel therapeutic targets for metastatic breast cancer intervention.