SARS-CoV-2 induces blood-brain barrier and choroid plexus barrier impairments and vascular inflammation in mice.

The coronavirus disease of 2019 (COVID-19) pandemic has led to more than 700 million confirmed cases and nearly 7 million deaths. Although severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus mainly infects the respiratory system, neurological complications are widely reported in both acute infection and long-COVID cases. Despite the success of vaccines and antiviral treatments, neuroinvasiveness of SARS-CoV-2 remains an important question, which is also centered on the mystery of whether the virus is capable of breaching the barriers into the central nervous system. By studying the K18-hACE2 infection model, we observed clear evidence of microvascular damage and breakdown of the blood-brain barrier (BBB). Mechanistically, SARS-CoV-2 infection caused pericyte damage, tight junction loss, endothelial activation and vascular inflammation, which together drive microvascular injury and BBB impairment. In addition, the blood-cerebrospinal fluid barrier at the choroid plexus was also impaired after infection. Therefore, cerebrovascular and choroid plexus dysfunctions are important aspects of COVID-19 and may contribute to neurological complications both acutely and in long COVID.

Curcumin protects from LPS-induced activation of astrocytes via AMPK pathway.

Curcumin, a phenolic pigment, plays an inhibitory role in astrocytes activation which are involved in the pathogenesis of neurological diseases and inflammatory responses. The present study aimed to investigate the underlying regulatory mechanism behind the therapeutic effect of curcumin on the lipopolysaccharide (LPS)-activated astrocytes in vitro. Specifically, we investigated the inhibitory effect of curcumin on LPS-induced astrocyte's proliferation. Additionally, we investigated whether the adenosine-monophosphate-activated protein kinase signaling (AMPK) pathway was involved in this process. Our data demonstrated that curcumin significantly increased the level of phosphorylated AMPK protein in LPS-activated astrocytes. In addition, our data demonstrated that curcumin play an inhibitory role on the migration, autophagy, the pro-inflammatory mediators by the AMPK signaling pathway in LPS-activated astrocytes. These results could shed light on understanding of molecular mechanism for the inhibition of curcumin on migration, autophagy, and the pro-inflammatory mediators during the process of astrocyte activation, and might contribute to a promising therapeutic intervention in the neurological diseases-related astrocytes activation.

Bioengineering of a human physiologically relevant microfluidic blood-cerebrospinal fluid barrier model.

The human blood-cerebrospinal fluid barrier (hBCSFB) plays a crucial role in regulating brain interstitial fluid homeostasis, and disruption of the hBCSFB is associated with various neurological diseases. Generation of a BCSFB model with human physiologically relevant structural and functional features is crucial to reveal the cellular and molecular basis of these diseases and discover novel neurologic therapeutic agents. Unfortunately, thus far, few humanized BCSFB models are available for basic and preclinical research. Here, we demonstrate a bioengineered hBCSFB model on a microfluidic device constructed by co-culturing primary human choroid plexus epithelial cells (hCPECs) and human brain microvascular endothelial cells (hBMECs) on the two sides of a porous membrane. The model reconstitutes tight junctions of the hBCSFB and displays a physiologically relevant molecular permeability. Using this model, we further generate a neuropathological model of the hBCSFB under neuroinflammation. Overall, we expect that this work will offer a high-fidelity hBCSFB model for studying neuroinflammation-related diseases.

Rational Design and Acoustic Assembly of Human Cerebral Cortex-Like Microtissues from hiPSC-Derived Neural Progenitors and Neurons.

Development of biologically relevant and clinically relevant human cerebral cortex models is demanded by mechanistic studies of human cerebral cortex-associated neurological diseases and discovery of preclinical neurological drug candidates. Here, rational design of human-sourced brain-like cortical tissue models is demonstrated by reverse engineering and bionic design. To implement this design, the acoustic assembly technique is employed to assemble hiPSC-derived neural progenitors and neurons separately in a label-free and contact-free manner followed by subsequent neural differentiation and culture. The generated microtissues encapsulate the neuronal microanatomy of human cerebral-cortex tissue that contains six-layered neuronal architecture, a 400-µm interlayer distance, synaptic connections between interlayers, and neuroelectrophysiological transmission. Furthermore, these microtissues are infected with herpes simplex virus type I (HSV-1) virus, and the HSV-induced pathogenesis associated with Alzheimer's disease is determined, including neuron loss and the expression of Aß. Overall, a high-fidelity human-relevant in vitro histotypic model is provided for the cerebral cortex, which will facilitate wide applications in probing the mechanisms of neurodegenerative diseases and screening the candidates for neuroprotective agents.

Microglia innate immune response contributes to the antiviral defense and blood-CSF barrier function in human choroid plexus organoids during HSV-1 infection.

The choroid plexus (ChP) is the source of cerebrospinal fluid (CSF). The ChP-CSF system not only provides the necessary cushion for the brain but also works as a sink for waste clearance. During sepsis, pathogens and host immune cells can weaken the ChP barrier and enter the brain, causing cerebral dysfunctions known as sepsis-associated encephalophagy. Here, we used human ChP organoid (ChPO) to model herpes simplex virus type 1 (HSV-1) infection and found ChP epithelial cells were highly susceptible to HSV-1. Since the current ChPO model lacks a functional innate immune component, particularly microglia, we next developed a new microglia-containing ChPO model, and found microglia could effectively limit HSV-1 infection and protect epithelial barrier in ChPOs. Furthermore, we found the innate immune cyclic GMP-AMP synthase (cGAS)-STING pathway and its downstream interferon response were essential, as cGAS inhibitor RU.512 or STING inhibitor H-151 abolished microglia antiviral function and worsened ChP barrier in organoids. These results together indicated that cGAS-STING pathway coordinates antiviral response in ChP and contributes to treating sepsis or related neurological conditions.

Cerebral Organoids for Modeling of HSV-1-Induced-Amyloid ß Associated Neuropathology and Phenotypic Rescue.

Herpes simplex virus type I (HSV-1) infection is a potential risk factor involved in the Amyloid ß (Aß) associated neuropathology. However, further understanding of the neuropathological effects of the HSV-1 infection is hampered by the limitations of existing infection models due to the distinct differences between human brains and other mammalians' brains. Here we generated cerebral organoid models derived from pluripotent stem cells to investigate the HSV-induced Aß associated neuropathology and the role of antiviral drugs in the phenotypic rescue. Our results identified that the HSV-1-infected cerebral organoids recapitulated Aß associated neuropathology including the multicellular Aß deposition, dysregulated endogenous AD mediators, reactive gliosis, neuroinflammation, and neural loss, indicating that cerebral organoids offer an opportunity for modeling the interaction of HSV-1 with the complex phenotypes across the genetic, cellular, and tissue levels of the human Alzheimer's disease (AD). Furthermore, we identified that two antiviral drugs, namely Ribavirin (RBV) and Valacyclovir (VCV), inhibited HSV-1 replication and rescued the neuropathological phenotypes associated with AD in the HSV-1-infected cerebral organoids, implying their therapeutic potential to slow down the progression of AD. Our study provides a high-fidelity human-relevant in-vitro HSV-1 infection model to reconstitute the multiscale neuropathological features associated with AD and discover therapeutic drug candidates relevant to the AD viral hypothesis.

Global Evolution of Skeletal Muscle Tissue Engineering: A Scientometric Research.

Skeletal muscle tissue engineering (SMTE) is of great significance in the study of skeletal muscle physiology and pathology, which could be used in skeletal muscle graft. The scientometric analysis of SMTE can help researchers to quickly understand the evolutive history, status, novelties, and trend of this field. In this study, we performed a scientometric study that can be used to construct and visualize networks of SMTE using VOSviewer. A total of 1384 documents published between 1994 and 2020 were retrieved and analyzed. Our results showed that number of publications in SMTE has increased slowly from 1994 to 2014 and has increased rapidly from 2015 to 2020. The geographical distribution of publications in terms of total publications about SMTE is concentrated in Europe and the United States. The most productive institution was University of Michigan, while Harvard University and the University of Pittsburgh were ranked the second and third places. SMTE influenced a wide spectrum of disciplines, including Biology and Medicine and Physical Sciences. In addition, the research hotspot of SMTE was expanding from seed cells to the combination with advanced strategies (electrostatic spinning, bioprinting, and materials) for emulating the highly bionic engineered skeletal muscle tissues. This study provided a unique perspective for understanding the history and trends of SMTE, which could help to promote the rapid development of the field. Impact statement Skeletal muscle tissue engineering (SMTE), which acts as an important branch of tissue engineering, hold a great promise in the study of skeletal muscle physiology and pathology. The field of SMTE has developed rapidly in recent decades while still lacking studies based on scientometric methods. This article provided the first scientometric study of SMTE from development trends and evolution of the field. The results indicated that the field of SMTE was experiencing rapid growth and had a significant impact on multiple fields, particularly in Biology and Medicine and Physical Sciences.

Peri-tumoral brain edema associated with glioblastoma correlates with tumor recurrence.

Glioblastoma is the most common malignant tumor of the brain. Despite advances in treatment, the prognosis for the condition has remained poor. Glioblastoma is often associated with peritumoral brain edema (PTBE), which can result in increased intracranial pressure and devastating neurological sequelae if left untreated. Surgery is the main treatment for glioblastoma, however current international surgical guidelines do not specify whether glioblastoma-induced PTBE tissue should be resected. In this study, we analyzed treatment outcomes of PTBE using surgical resection. We performed a retrospective analysis of 255 cases of glioblastoma between 2014 and 2016, and found that a significant proportion of patients had a degree of PTBE. We found that surgical resection led to reduction in midline shift that had resulted from edema, however, postoperative complications and KPS scores were not significantly different in the two conditions. We also observed a delay in glioblastoma recurrence in patients undergoing PTBE tissue resection vs patients without resection of PTBE tissue. Interestingly, there was an abnormal expression of tumor associated genes in PTBE, which has not been previously been found. Taken together, this study indicates that glioblastoma-induced PTBE should be investigated further particularly as the tumor microenvironment is a known therapeutic target and therefore interactions between the microenvironment and PTBE should be explored. This study also highlights the importance of resection of PTBE tissue to not only reduce the mechanical obstruction associated with edema but also to delay recurrence of glioblastoma.

Herpes simplex virus type 1 infection leads to neurodevelopmental disorder-associated neuropathological changes.

Neonatal herpes simplex virus type 1 (HSV-1) infections contribute to various neurodevelopmental disabilities and the subsequent long-term neurological sequelae into the adulthood. However, further understanding of fetal brain development and the potential neuropathological effects of the HSV-1 infection are hampered by the limitations of existing neurodevelopmental models due to the dramatic differences between humans and other mammalians. Here we generated in vitro neurodevelopmental disorder models including human induced pluripotent stem cell (hiPSC)-based monolayer neuronal differentiation, three-dimensional (3D) neuroepithelial bud, and 3D cerebral organoid to study fetal brain development and the potential neuropathological effects induced by the HSV-1 infections. Our results revealed that the HSV-1-infected neural stem cells (NSCs) exhibited impaired neural differentiation. HSV-1 infection led to dysregulated neurogenesis in the fetal neurodevelopment. The HSV-1-infected brain organoids modelled the pathological features of the neurodevelopmental disorders in the human fetal brain, including the impaired neuronal differentiation, and the dysregulated cortical layer and brain regionalization. Furthermore, the 3D cerebral organoid model showed that HSV-1 infection promoted the abnormal microglial activation, accompanied by the induction of inflammatory factors, such as TNF-α, IL-6, IL-10, and IL-4. Overall, our in vitro neurodevelopmental disorder models reconstituted the neuropathological features associated with HSV-1 infection in human fetal brain development, providing the causal relationships that link HSV biology with the neurodevelopmental disorder pathogen hypothesis.

Global Trends of Organoid and Organ-On-a-Chip in the Past Decade: A Bibliometric and Comparative Study.

Organoid and organ-on-a-chip have evolved as two critical but distinct approaches to develop human physiologically and pathologically relevant in vitro models. Although rapid progress has been witnessed in the past decade, there is no systematic comparison of their status and trends based on the scientometric analysis. In this study, we performed a comparative study of organoid and organ-on-a-chip using bibliometric methods. A total of 2790 documents published between 2009 and 2018 were retrieved and analyzed. Our results showed that both organoid and organ-on-a-chip had experienced rapid growth in their academic and social impacts and influenced a wide spectrum of disciplines, but with a major distinct focus on Cell Biology and Nanoscience Nanotechnology, respectively. The hotspots of organoid research were expanding from in vitro differentiation of Lgr5 stem cells to mechanistic studies of diseases, while the hotspots of the organ-on-a-chip research were transiting from the establishment of microfluidic devices for in vitro cell culture to stem cell differentiation and tissue engineering. Interestingly, there was a growing trend of combining organoid with organ-on-a-chip in the last few years. This comparative study presented a unique perspective to understand the evolutive history and future trends of organoid and organ-on-a-chip for emerging human relevant in vitro organotypic models. Impact statement Organoid and organ-on-a-chip, which served as emerging human physiologically and pathologically relevant in vitro models, hold a great promise to revolutionize the conventional paradigm in basic and clinical research. The fields of organoid and organ-on-a-chip have advanced rapidly over the past decade while lacking comparative studies based on bibliometric methods. This article provided the first scientometric study of these two fields from the unique perspectives of their research hotspots, influencing scientific areas, and global trends. Our bibliometric work will provide a quantitative and timely summary of these two fields for the researchers in the tissue engineering field.

Mesenchymal stem cells inhibited the inflammation and oxidative stress in LPS-activated microglial cells through AMPK pathway.

Microglia are the resident mononuclear immune cells of the central nervous system (CNS) and the activation of microglia contributes to the production of excessive neurotoxic factors. In particular, the overproduction of neurotoxic factors has critical effects on the development of brain injuries and neurodegenerative diseases. The human bone marrow-derived mesenchymal stem cells (hBM-MSCs) have blossomed into an effective approach with great potential for the treatment of neurodegenerative diseases and gliomas. The present study aimed to investigate the mechanism behind the therapeutic effect of hBM-MSCs on the activation of microglia in vitro. Specifically, the hBM-MSCs significantly inhibited the proliferation of lipopolysaccharide-activated microglial cells (LPS)-activated microglial cells. Additionally, we investigated whether the adenosine-monophosphate-activated protein kinase signaling (AMPK) pathway was involved in this process. Our data demonstrated that hBM-MSCs significantly increased the phosphorylated AMPK in LPS-activated microglial cells. In addition, our study indicated the inhibitory effect of hBM-MSCs on the pro-inflammatory mediators and oxidative stress by the AMPK pathway in LPS-activated microglial cells. These results could shed light on the understanding of the molecular basis for the inhibition of hBM-MSCs on LPS-activated microglial cells and provide a molecular mechanism for the hBM-MSCs implication in brain injuries and neurodegenerative diseases.

Curcumin potentiates the galbanic acid-induced anti-tumor effect in non-small cell lung cancer cells through inhibiting Akt/mTOR signaling pathway.

BACKGROUND: Galbanic acid (GBA), which is known as a sesquiterpene coumarin, has been reported to have various anti-tumor activities in different cells. Our study intended to investigate whether curcumin potentiates GBA-induced anti-tumor effect in non-small cell lung cancer cells. MATERIALS AND METHODS: The combined effect of GBA and curcumin on cell viability was examined by MTT analysis. Cellular apoptosis was evaluated by flow cytometry analysis. Autophagy was defined by autophagosome observed by confocal microscopy after infected with GFP-LC3 adenovirus. In addition, the expression of marker proteins involved in cell apoptosis, autophagy, and Akt/mTOR signaling pathway were estimated by qRT-PCR and Western Blotting assay. RESULTS: 15 µM curcumin combined with 40 µM GBA could obtain better synergistic repressive efficacy on cell viability and notably induced cell apoptosis in A549 cells. Besides, curcumin in alliance with GBA could significantly inhibit cell migration and invasion. GFP-LC3 infection experiments elaborated that curcumin could potentiate GBA induced cell autophagy and restrain the phosphorylation of Akt/mTOR/P70s6k signaling pathway. What's more, the reaction of migration, apoptosis, and autophagy induced by curcumin and GBA treatment could be reversed by mTOR inhibitor rapamycin and AKT activator insulin.

NADPH Oxidase Signaling Pathway Mediates Mesenchymal Stem Cell-Induced Inhibition of Hepatic Stellate Cell Activation.

BACKGROUND: Bone marrow-derived mesenchymal stem cells (BMSCs) have blossomed into an effective approach with great potential for the treatment of liver fibrosis. The aim of this study was to investigate the underlying antifibrosis mechanisms by which the BMSC inhibit activated hepatic stellate cells (HSCs) in vivo and in vitro. METHODS: To study the effect of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) on activated HSCs, we used HSCs and the coculture systems to evaluate the inhibition of activated HSCs from the aspects of the apoptosis of activated HSCs. In addition, activation of NADPH oxidase pathway and the changes in liver histopathology were tested by using the carbon tetrachloride- (CCl4-) induced liver fibrosis in mice. RESULTS: Introduction of hBM-MSCs significantly inhibited the proliferation of activated HSCs by inducing the apoptosis process of activated HSCs. The effect of hBM-MSCs reduced the signaling pathway of NADPH oxidase in activated HSCs. Besides, the signaling pathway of NADPH oxidase mediated hBM-MSC upregulation of the expression of the peroxisome proliferator-activated receptor γ and downregulation of the expression of α1(I) collagen and alpha-smooth muscle actin (α-SMA) in activated HSCs. Moreover, the hBM-MSC-induced decrease in the signaling pathway of NADPH oxidase was accompanied by the decrease of the activated HSC number and liver fibrosis in a mouse model of CCl4-induced liver fibrosis. CONCLUSION: The hBM-MSCs act as a promising drug source against liver fibrosis development with respect to hepatopathy as a therapeutic target.

Curcumin Inhibits Monocyte Chemoattractant Protein-1 Expression in TNF-α induced Astrocytes Through AMPK Pathway.

Curcumin, a phenolic pigment, plays an inhibitory role in astrocytes activation, a key step for neuropathic pain (NP). The present study aimed to investigate the mechanism behind the therapeutic effect of Curcumin on NP in vitro. Specifically, we investigated the inhibitory effect of Curcumin on tumor necrosis factor-α (TNF-α)-induced astrocyte migration. We also studied the effects of Curcumin on monocyte chemoattractant protein-1(MCP-1) expression and activity, as well as super oxide dismutase-2 (SOD2) expression and activity in TNF-α-induced astrocytes. Additionally, we investigated whether the adenosine-monophosphate-activated protein kinase signaling (AMPK) pathway was involved in this process. Our data demonstrated that Curcumin inhibited TNF-α-induced astrocytes migration, decreased MCP-1 expression, and up-regulated SOD2 expression in TNF-α-induced astrocytes in vitro. Our study also indicated that this process was mediated through the AMPK signaling pathway, as addition of Curcumin significantly increased the level of phosphorylated AMPK protein. Furthermore, the specific AMPK activator AICAR (5-aminoimidazole-4-carboxamide 1-D-ribofuranoside) mimicked the effects of Curcumin, whereas a selective AMPK inhibitor Compound C (also called dorsomorphin) partially blocked its function. These results could shed light on understanding of the molecular basis for the inhibition of Curcumin on MCP-1 expression during the process of astrocyte activation, and provide a molecular mechanism for using Curcumin in neuropathic pain.

Sex-determining region Y-box 9 acts downstream of NADPH oxidase to influence the effect of leptin on PPARγ1 expression in hepatic stellate cells.

Leptin, an adipocyte-derived hormone, promotes liver fibrogenesis and inhibits the expression of peroxisome-proliferator activated receptor γ (PPARγ), a key transcription factor in inhibition of hepatic stellate cell (HSC) activation, in HSCs. This research aimed to further investigate the mechanisms underlying leptin regulation of PPARγ1 in HSCs in vivo and in vitro. Results demonstrated that sex-determining region Y-box 9 (Sox9) could bind to a site around -2275 within leptin response region of PPARγ1 promoter and inhibited PPARγ1 expression. Sox9 upregulated the expressions of α1(I)collagen and alpha-smooth muscle actin in HSCs. Leptin stimulated Sox9 expression and Sox9 binding to PPARγ1 promoter. The signaling pathways of NADPH oxidase, ß-catenin, and delta-like homolog1 (DLK1) mediated leptin upregulation of Sox9 expression. Moreover, there existed crosstalk between NADPH oxidase pathway and ß-catenin or DLK1 signaling pathway. Human liver specimens of cirrhosis were shown to be of a large number of the positive HSCs for p47phox (playing a central role in NADPH oxidase activity), 4-hydroxynonenal (a lipid peroxidation product), Sox9, and α-smooth muscle actin whereas PPARγ-positive HSCs were rarely detected. These results might deepen understanding of the molecular mechanisms for leptin inhibition of PPARγ1 expression in HSCs and for the liver fibrosis associated with leptin.

Curcumin regulates peroxisome proliferator-activated receptor-γ coactivator-1α expression by AMPK pathway in hepatic stellate cells in vitro.

Curcumin exerts an inhibitory effect on hepatic stellate cell (HSC) activation, a key step for liver fibrogenesis, and on liver fibrosis by up-regulation of peroxisome proliferator-activated receptor-γ (PPARγ) expression. PPARγ plays a crucial role in suppression of HSC activation. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) functions as a co-activator for PPARγ. Therefore, researches on the effect of curcumin on PGC-1α might contribute to understanding of the mechanisms underlying curcumin inhibition of HSC activation and liver fibrosis through PPARγ. The present study aimed to investigate the effect of curcumin on PGC-1α expression in HSCs in vitro and examine the underlying molecular mechanisms by western blot, reat-time PCR, and transfection. Our results showed that curcumin stimulation increased PGC-1α expression and the effects of curcumin on PGC-1α expression were correlated with the activation of adenosine monophosphate-activated protein kinase (AMPK). Curcumin increased superoxide dimutase-2 (SOD2) transcription and activity by AMPK/PGC-1α axis. Moreover, PGC-1α was demonstrated to inhibit α1(I) collagen (a marker for liver fibrosis) transcription in cultured HSCs. These results demonstrated the promotion effect of curcumin on PGC-1α expression through AMPK pathway, which led to the increases in PPARγ activity and in SOD-2 transcription and activity. These data might suggest a possible new explanation for the inhibitory effect of curcumin on HSC activation and on liver fibrogenesis.

GATA binding protein 2 mediates leptin inhibition of PPARγ1 expression in hepatic stellate cells and contributes to hepatic stellate cell activation.

Hepatic stellate cell (HSC) activation is a crucial step in the development of liver fibrosis. Peroxisome-proliferator activated receptor γ (PPARγ) exerts a key role in the inhibition of HSC activation. Leptin reduces PPARγ expression in HSCs and plays a unique role in promoting liver fibrosis. The present studies aimed to investigate the mechanisms underlying leptin regulation of PPARγ1 (a major subtype of PPARγ) in HSCs in vivo and in vitro. Results revealed a leptin response region in mouse PPARγ1 promoter and indicated that the region included a GATA binding protein binding site around position -2323. GATA binding protein-2 (GATA-2) could bind to the site and inhibit PPARγ1 promoter activity in HSCs. Leptin induced GATA-2 expression in HSCs in vitro and in vivo. GATA-2 mediated leptin inhibition of PPARγ1 expression by its binding site in PPARγ1 promoter in HSCs and GATA-2 promoted HSC activation. Leptin upregulated GATA-2 expression through ß-catenin and sonic hedgehog pathways in HSCs. Leptin-induced increase in GATA-2 was accompanied by the decrease in PPARγ expression in HSCs and by the increase in the activated HSC number and liver fibrosis in vivo. Our data might suggest a possible new explanation for the promotion effect of leptin on liver fibrogenesis.