Nucleic acid degradation as barrier to gene delivery: a guide to understand and overcome nuclease activity.

Gene therapy is on its way to revolutionize the treatment of both inherited and acquired diseases, by transferring nucleic acids to correct a disease-causing gene in the target cells of patients. In the fight against infectious diseases, mRNA-based therapeutics have proven to be a viable strategy in the recent Covid-19 pandemic. Although a growing number of gene therapies have been approved, the success rate is limited when compared to the large number of preclinical and clinical trials that have been/are being performed. In this review, we highlight some of the hurdles which gene therapies encounter after administration into the human body, with a focus on nucleic acid degradation by nucleases that are extremely abundant in mammalian organs, biological fluids as well as in subcellular compartments. We overview the available strategies to reduce the biodegradation of gene therapeutics after administration, including chemical modifications of the nucleic acids, encapsulation into vectors and co-administration with nuclease inhibitors and discuss which strategies are applied for clinically approved nucleic acid therapeutics. In the final part, we discuss the currently available methods and techniques to qualify and quantify the integrity of nucleic acids, with their own strengths and limitations.

Crystalline Polyphenylene Covalent Organic Frameworks.

The synthesis of crystalline polyphenylene covalent organic frameworks (COFs) was accomplished by linking fluorinated tris(4-acetylphenyl)benzene building units using aldol cyclotrimerization. The structures of the two COFs, reported here, were confirmed by powder X-ray diffraction techniques, Fourier transform infrared, and solid-state 13C CP/MAS NMR spectroscopy. The results showed that the COFs were porous and chemically stable in corrosive, harsh environments for at least 1 week. Accordingly, postsynthetically modified derivatives of these COFs using primary amines showed CO2 uptake from air and flue gas.

Deconvolving Passive and Active Targeting of Liposomes Bearing LDL Receptor Binding Peptides Using the Zebrafish Embryo Model.

Improving target versus off-target ratio in nanomedicine remains a major challenge for increasing drug bioavailability and reducing toxicity. Active targeting using ligands on nanoparticle surfaces is a key approach but has limited clinical success. A potential issue is the integration of targeting ligands also changes the physicochemical properties of nanoparticles (passive targeting). Direct studies to understand the mechanisms of active targeting and off-targeting in vivo are limited by the lack of suitable tools. Here, the biodistribution of a representative active targeting liposome is analyzed, modified with an apolipoprotein E (ApoE) peptide that binds to the low-density lipoprotein receptor (LDLR), using zebrafish embryos. The ApoE liposomes demonstrated the expected liver targeting effect but also accumulated in the kidney glomerulus. The ldlra-/- zebrafish is developed to explore the LDLR-specificity of ApoE liposomes. Interestingly, liver targeting depends on the LDLR-specific interaction, while glomerular accumulation is independent of LDLR and peptide sequence. It is found that cationic charges of peptides and the size of liposomes govern glomerular targeting. Increasing the size of ApoE liposomes can avoid this off-targeting. Taken together, the study shows the potential of the zebrafish embryo model for understanding active and passive targeting mechanisms, that can be used to optimize the design of nanoparticles.

Association of systemic inflammation with the obesity paradox in cancer: results from multi-cohort studies.

AIMS: This study aimed to explore whether the obesity paradox exists in overall and specific cancers and to investigate the role of systemic inflammation in the obesity paradox. METHODS: The Cox proportional hazard model was used to explore the relationship between body mass index (BMI) and all-cause mortality. The mediated effect was used to investigate the proportion of systemic inflammation mediating the relationship between BMI and cancer survival risk. RESULTS: The survival probability showed a step-like increase with an increase in BMI regardless of pathological stage. Approximately 10.8%-24.0% of the overall association between BMI and all-cause mortality in cancer was mediated by inflammation. In the internal validation, we found evidence of the obesity paradox in all body composition obtained using BIA, with inflammation remaining an important mediating factor. Furthermore, we also validated the existence of the obesity paradox of cancer in NHANES. Systemic inflammation remains an important factor in mediating the association between BMI and prognosis in cancer patients. CONCLUSIONS: The obesity paradox is prevalent in most cancers, except for hepatic biliary cancer and breast cancer. Inflammation may be one of the true features of the obesity paradox in cancer.

Remnant cholesterol is an effective biomarker for predicting survival in patients with breast cancer.

BACKGROUND: Breast cancer is the most common malignancy in women worldwide. The relationship between remnant cholesterol (RC) and the prognosis of patients with breast cancer has not been clearly reported. This study investigated the prognostic value of RC in predicting mortality in patients with breast cancer. METHODS: This study prospectively analysed 709 women patients with breast cancer from the Investigation on Nutrition Status and Clinical Outcome of Common Cancers (INSCOC) project. Restricted cubic splines were used to analyse the dose-response relationship between RC and breast cancer mortality. The Kaplan-Meier method was used to evaluate the overall survival of patients with breast cancer. A Cox regression analyses was performed to assess the independent association between RC and breast cancer mortality. Inverse probability of treatment weighting (IPTW) using the propensity score was used to reduce confounding. Sensitivity analysis was performed after excluding patients with underlying diseases and survival times shorter than one year. RESULTS: A linear dose-response relationship was identified between RC and the risk of all-cause mortality in patients with breast cancer (p = 0.036). Kaplan-Meier survival analysis and log-rank test showed that patients with high RC levels had poorer survival than those with low RC levels (p = 0.007). Univariate and multivariate Cox regression analyses showed that RC was an independent risk factor for mortality in women patients with breast cancer. IPTW-adjusted analyses and sensitivity analyses showed that CR remained a prognostic factor. CONCLUSIONS: RC is an independent risk factor for the prognosis of patients with breast cancer, and patients with higher RC levels have poorer survival.

miR-134-5p inhibits osteoclastogenesis through a novel miR-134-5p/Itgb1/MAPK pathway.

Osteoporosis affects approximately 200 million people and severely affects quality of life, but the exact pathological mechanisms behind this disease remain unclear. Various miRNAs have been shown to play a predominant role in the regulation of osteoclast formation. In this study, we explored the role of miR-134-5p in osteoclastogenesis both in vivo and in vitro. We constructed an ovariectomized (OVX) mouse model and performed microarray analysis using bone tissue from OVX mice and their control counterparts. Quantitative RT-PCR data from bone tissue and bone marrow macrophages (BMMs) confirmed the decreased expression of miR-134-5p in OVX mice observed in microarray analysis. In addition, a decrease in miR-134-5p was also observed during induced osteoclastogenesis of BMMs collected from C57BL/6N mice. Through transfection with miR-134-5p agomirs and antagomirs, we found that miR-134-5p knockdown significantly accelerated osteoclast formation and cell proliferation and inhibited apoptosis. Furthermore, a luciferase reporter assay showed that miR-134-5p directly targets the integrin surface receptor gene Itgb1. Cotransfection with Itgb1 siRNA reversed the effect of the miR-134-5p antagomir in promoting osteoclastogenesis. Moreover, the abundance levels of MAPK pathway proteins phosphorylated-p38 (p-p38) and phosphorylated-ERK (p-ERK) were significantly increased after transfection with the miR-134-5p antagomir but decreased after transfection with the miR-134-5p agomir or Itgb1 siRNA, which indicated a potential relationship between the miR-134-5p/Itgb1 axis and the MAPK pathway. Collectively, these results revealed that miR-134-5p inhibits osteoclast differentiation of BMMs both in vivo and in vitro and that the miR-134-5p/Itgb1/MAPK pathway might be a potential target for osteoporosis therapy.

Hydrazonyl Sultones as Stable Tautomers of Highly Reactive Nitrile Imines for Fast Bioorthogonal Ligation Reaction.

Here we report the design and synthesis of a new class of bioorthogonal reagents called hydrazonyl sultones (HS) that serve as stable tautomers of highly reactive nitrile imines (NI). Compared to the photogenerated NI, HS display a broad range of aqueous stability and tunable reactivity in a 1,3-dipolar cycloaddition reaction, depending on substituents, sultone ring structure, and solvent conditions. DFT calculations have provided vital insights into the HS → NI tautomerism, including a base-mediated anionic tautomerization pathway and a small activation barrier. Comparative kinetic analysis of tetrazole vs HS-mediated cycloadditions reveals that a tiny fraction of the reactive NI (∼15 ppm) is present in the tautomeric mixture, underpinning the extraordinary stability of the six-membered HS. We further demonstrate the utilities of HS in selective modification of bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN)-lysine-containing nanobodies in phosphate buffered saline and fluorescent labeling of a BCN-lysine-encoded transmembrane glucagon receptor on live cells.

Cholesterol-modified prognostic nutritional index (CPNI) as an effective tool for assessing the nutrition status and predicting survival in patients with breast cancer.

BACKGROUND: Malnutrition is associated with poor overall survival (OS) in breast cancer patients; however, the most predictive nutritional indicators for the prognosis of patients with breast cancer are not well-established. This study aimed to compare the predictive effects of common nutritional indicators on OS and to refine existing nutritional indicators, thereby identifying a more effective nutritional evaluation indicator for predicting the prognosis in breast cancer patients. METHODS: This prospective study analyzed data from 776 breast cancer patients enrolled in the "Investigation on Nutritional Status and its Clinical Outcome of Common Cancers" (INSCOC) project, which was conducted in 40 hospitals in China. We used the time-dependent receiver operating characteristic curve (ROC), Kaplan-Meier survival curve, and Cox regression analysis to evaluate the predictive effects of several nutritional assessments. These assessments included the patient-generated subjective nutrition assessment (PGSGA), the global leadership initiative on malnutrition (GLIM), the controlling nutritional status (CONUT), the nutritional risk index (NRI), and the prognostic nutritional index (PNI). Utilizing machine learning, these nutritional indicators were screened through single-factor analysis, and relatively important variables were selected to modify the PNI. The modified PNI, termed the cholesterol-modified prognostic nutritional index (CPNI), was evaluated for its predictive effect on the prognosis of patients. RESULTS: Among the nutritional assessments (including PGSGA, GLIM, CONUT, NRI, and PNI), PNI showed the highest predictive ability for patient prognosis (time-dependent ROC = 0.58). CPNI, which evolved from PNI, emerged as the superior nutritional index for OS in breast cancer patients, with the time-dependent ROC of 0.65. It also acted as an independent risk factor for mortality (p < 0.05). Moreover, the risk of malnutrition and mortality was observed to increase gradually among both premenopausal and postmenopausal age women, as well as among women categorized as non-overweight, overweight, and obese. CONCLUSIONS: The CPNI proves to be an effective nutritional assessment tool for predicting the prognosis of patients with breast cancer.

Tuning the Cross-Linking Density and Cross-Linker in Core Cross-Linked Polymeric Micelles and Its Effects on the Particle Stability in Human Blood Plasma and Mice.

Core cross-linked polymeric micelles (CCPMs) are designed to improve the therapeutic profile of hydrophobic drugs, reduce or completely avoid protein corona formation, and offer prolonged circulation times, a prerequisite for passive or active targeting. In this study, we tuned the CCPM stability by using bifunctional or trifunctional cross-linkers and varying the cross-linkable polymer block length. For CCPMs, amphiphilic thiol-reactive polypept(o)ides of polysarcosine-block-poly(S-ethylsulfonyl-l-cysteine) [pSar-b-pCys(SO2Et)] were employed. While the pCys(SO2Et) chain lengths varied from Xn = 17 to 30, bivalent (derivatives of dihydrolipoic acid) and trivalent (sarcosine/cysteine pentapeptide) cross-linkers have been applied. Asymmetrical flow field-flow fraction (AF4) displayed the absence of aggregates in human plasma, yet for non-cross-linked PM and CCPMs cross-linked with dihydrolipoic acid at [pCys(SO2Et)]17, increasing the cross-linking density or the pCys(SO2Et) chain lengths led to stable CCPMs. Interestingly, circulation time and biodistribution in mice of non-cross-linked and bivalently cross-linked CCPMs are comparable, while the trivalent peptide cross-linkers enhance the circulation half-life from 11 to 19 h.

Association between the Dietary Inflammatory Index and All-Cause Mortality in Adults with Obesity.

INTRODUCTION: The dietary inflammatory index (DII) is associated with numerous chronic noncommunicable diseases. Previous studies have shown that the pro-inflammatory DII categories are associated with abdominal and simple obesity. However, the association between DII and mortality in patients with abdominal obesity and simple overweight or obesity remains unclear. METHODS: We used data from the US National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018. A DII >0 (positive DII) was defined as a pro-inflammatory diet. A restricted cubic spline curve was used to describe the trend between DII and all-cause mortality. We then examined the association between DII and all-cause mortality in different body types using a Cox regression analysis and investigated the differences between sexes. Finally, the mediating effects of systemic inflammation were explored. RESULTS: A pro-inflammatory diet increased all-cause mortality in adults with abdominal obesity (aHR: 1.31, 95% confidence interval [CI]: 1.11-1.54; p < 0.001) and with simple overweight or obesity (aHR: 1.30, 95% CI: 1.11-1.53; p < 0.001). In addition, the most pro-inflammatory DII increased the risk of mortality by 43% (hazard ratio [HR]: Q4 vs. Q1 = 1.43, 95% CI = 1.14-1.79; p = 0.002; p for trend = 0.003) and 39% (HR: Q4 vs. Q1 = 1.39, 95% CI = 1.13-1.74; p = 0.003; p for trend = 0.009) in participants with abdominal obesity and with simple overweight or obesity, respectively. However, this association was not present in normal-sized participants. Compared with men, women resisted the effects of a pro-inflammatory diet. Mediation analysis showed that white blood cell and neutrophil were mediators of the association between DII and all-cause mortality (p < 0.001). CONCLUSION: A pro-inflammatory diet is associated with all-cause mortality in adults with abdominal obesity and simple overweight or obesity, and this effect differs between men and women. Systemic inflammation may mediate the association between DII and all-cause mortality.

Roles of the hsa_circ_0013880/USP32/Rap1b axis in the proliferation and apoptosis of acute myeloid leukemia cells.

Acute myeloid leukemia (AML) is a myeloid malignancy with generally high mortality. Although recent advances in AML research have revealed that circRNAs play significant roles in AML progression, our understanding of the leukemogenic mechanism of circRNAs remains very limited. In this study, increased expression of hsa_circ_0013880 was observed in bone marrow mononuclear cells (BMNCs) of AML patients. Overexpression of hsa_circ_0013880 promotes AML cell proliferation and migration and reduces cell apoptosis. Mechanistically, hsa_circ_0013880 could elevate the expression of USP32, a deubiquitinating enzyme that is highly expressed in the BMNCs of AML patients. Given the deubiquitination function of USP32, we further hypothesize that USP32 may mediate the malignant behaviors of AML cells by regulating the stability of Ras-related protein (Rap1b). At the molecular level, we find that silencing of USP32 increases ubiquitinated Rap1b. Overexpression of Rap1b restores the effects of USP32 knockdown, which further verifies our hypothesis. In addition, we propose another hypothesis that a potential regulatory network among hsa_circ_0013880, miR-148a-3p/miR-20a-5p and USP32 might exist in the development of AML, according to bioinformatics website predictions and our preliminary experimental verification. Overall, our findings will enrich the understanding of the hsa_circ_0013880/USP32/Rap1b axis in AML development, which may contribute to the development of novel therapeutic strategies for AML.

A novel inflammation-nutrition biomarker score for predicting prognosis of patients with cancer: results from a multicenter study.

BACKGROUND: This study aimed to develop an innovative inflammation-nutrition biomarker score (INS) system to stratify the prognoses of patients with cancer. METHODS: A total of 5,221 patients with cancer from multiple centers in China between June 2010 and December 2017 were enrolled in this prospective cohort study. We compared the commonly used inflammation and nutrition biomarkers and selected the most valuable to develop the novel INS system. Survival curves were assessed using the Kaplan-Meier method and the log-rank test to evaluate the difference in survival rates between groups. The Cox proportional hazards model was used to investigate the association between biomarkers and all-cause mortality. RESULTS: As the risk stratification of INS increased (1 to 5), the rate of death for cancer patients gradually increased (25.43% vs. 37.09% vs. 44.59% vs. 56.21% vs. 61.65%, p < 0.001). The INS system was associated with all-cause mortality in patients with cancer. Patients with both high inflammation and nutrition risk (INS = 5) were estimated to have much worse prognosis than those with neither (HR, 2.606; 95%CI, 2.261-3.003, p < 0.001). Subsequently, the results of randomized internal validation also confirmed that INS system had an ideal effect in identifying adverse outcomes. In addition, the INS system could be used as a supplement to pathological stages in prognosis assessment, and had a higher predictive value in comparison with the constitute biomarkers. Patients with a high INS had less functional ability, reduced quality of life, and were at high risk of malnutrition, cachexia, and poor short-term outcomes. CONCLUSION: The INS system based on inflammation and nutrition biomarkers is a simple and effective prognostic stratification tool for patients with cancer, which can provide a valuable reference for clinical prognosis assessment and treatment strategy formulation.

Prognostic importance of systemic inflammation and insulin resistance in patients with cancer: a prospective multicenter study.

BACKGROUND: Systemic inflammation and insulin resistance (IR) are often associated with poor prognosis in cancer. This study aimed to investigate the prognostic value of surrogate systemic inflammation and IR indices in patients with cancer. METHODS: This multicenter prospective study included 5,221 patients with cancer, with a mean age of 59.41±11.15 years, of whom 3,061 (58.6%) were male. The surrogate IR indices included low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LHR) ratio, total cholesterol to high-density lipoprotein cholesterol (TC/ HDL-c) ratio, triglyceride to high-density lipoprotein cholesterol (TG/HDL-c) ratio, and fasting triglyceride glucose (TyG). Prognostic receiver operator characteristic (ROC) curves and C-indices were used to select a better surrogate IR index in patients with cancer. The prognostic value of the indicators was evaluated using univariate and multivariate survival analyses. RESULTS: In this study, the median survival time of patients was 44.5 (40.5-51.4) months, and the overall mortality in the 12-month period was 1,115 (53.7%), with 196 mortality events per 1,000 patient-years of patients' follow-up. The prognostic ROC curve and C-index suggested that the prognostic value of LHR was better than that of the other IR indices. The multivariate-adjusted hazard ratios (HRs) for overall survival (OS) were higher in patients with high C-reactive protein (CRP) (HR, 1.51; 95% confidence interval [CI]: 1.38-1.65) and high LHR (HR, 1.20; 95% CI: 1.06-1.37), respectively. The mortality rate of patients with both high CRP and LHR was 1.75-fold higher than that of patients with both low CRP and LHR. CONCLUSION: Both CRP and LHR showed good survival predictions in patients with cancer. CRP combined with LHR can improve the predictive power of patients with cancer.

Lymphocyte to C-reactive protein ratio could better predict the prognosis of patients with stage IV cancer.

BACKGROUND: Systemic inflammation is currently regarded as a hallmark of cancer. This study aimed to accurately clarify the prognostic value of various inflammatory markers in patients with stage IV cancer. METHODS: This study assessed 2,424 patients with cancer diagnosed with cancer in tumor, node, metastasis (TNM) stage IV. After evaluating the predictive value of 13 inflammatory indicators for patient prognosis using the C index, the lymphocyte C-reactive protein ratio (LCR) was selected to elucidate the prognostic and predictive values in patients with stage IV cancer. Kaplan-Meier and Cox proportional hazards regression models were used to analyze long-term survival. RESULTS: A total of 1,457 men (60.1%) and 967 women (39.9%) diagnosed with TNM stage IV cancer were enrolled. A ratio of 2,814 was defined as the optimal cut-off value for the LCR. The LCR was the most accurate prognosis predictor for patients with stage IV cancer among the 13 inflammatory nutritional markers evaluated. The multivariate-adjusted restricted cubic spline plot suggested that LCR had an L-shaped dose-response association with all-cause mortality risk. Patients with lower LCR levels tended to present with worse prognoses. Kaplan-Meier curves and log-rank test results showed that the high LCR groups (LCR ≥ 2,814) exhibited a better prognosis, whereas patients with stage IV cancer of different sex and tumor types (for example, gastrointestinal tumor, non-gastrointestinal tumor, and lung cancer) had a worse survival time. CONCLUSION: The LCR score can be regarded as a stable and useful biomarker to predict prognosis in patients with TNM stage IV compared to other evaluated inflammation indicators.

TLS/FUS-ERG fusion gene in acute leukemia and myelodysplastic syndrome evolved to acute leukemia: report of six cases and a literature review.

To investigate the pathogenesis and the refractory/relapse mechanisms in patients with t(16;21)(p11;q22), we retrospectively analyzed the clinical data of six cases in our hospital and sixty-two cases reported in the literature. Among the patients in our hospital, five cases were diagnosed as acute leukemia, and one was myelodysplastic syndrome evolved to acute myeloid leukemia, harboring TLS/FUS-ERG fusion gene; all the cases were detected t(16;21)(p11;q22) translocation, and five cases showed additional chromosomal abnormalities. We firstly report a novel three-way translocation t(11;16;21)(q13;p11;q22), which may affect the prognosis of leukemia with TLS-ERG fusion gene because this patient shows a more satisfactory treatment effect and deeper remission. And we found patients with TLS-ERG are more likely to have bone and arthrosis pain. Besides, CD56 and CD123 were positive in these cases, which are related to poor prognosis and the character of refractory. Moreover, some gene mutations are involved, and GATA2 and SMAD4 mutations were identified when the disease progressed from myelodysplastic syndrome to leukemia. Among sixty-two patients reported in the literature, valid positive percent of CD56 and CD123 were 81% and 14.3%, respectively. Mutation of the RUNX1 gene was detected in four cases, and one patient had multiple mutations, including BCOR, PLCG1, DIS3, BRAF, JAK2, and JAK3. The prominent feature of leukemia carrying the TLS/FUS-ERG gene is its poor prognosis. The relevant mechanism includes new mutation, jumping translocation, different transcripts, and so on. The mechanism still acquaints scarcely, which requires further study.

Comprehensive comparison of the prognostic value of systemic inflammation biomarkers for cancer cachexia: a multicenter prospective study.

AIMS: Systemic inflammation plays an important role in cancer cachexia. However, among the systemic inflammatory biomarkers, it is unclear which has optimal prognostic value for cancer cachexia. METHODS: The Kaplan-Meier method was used and the log-rank analysis was performed to estimate survival differences between groups. Cox proportional hazard regression analyses were conducted to assess independent risk factors for all-cause mortality. RESULTS: The C-reactive protein-to-albumin ratio (CAR) was the optimal prognostic assessment tool for patients with cancer cachexia, with 1-, 3-, and 5-year predictive powers of 0.650, 0.658, and 0.605, respectively. Patients with a high CAR had significantly lower survival rates than those with a low CAR. Moreover, CAR can differentiate the prognoses of patients with the same pathological stage. Cox proportional risk regression analyses showed that a high CAR was an independent risk factor for cancer cachexia. For every standard deviation increase in CAR, the risk of poor prognosis for patients with cancer cachexia was increased by 20% (hazard ratio = 1.200, 95% confidence interval = 1.132-1.273, P < 0.001). CONCLUSIONS: CAR is an effective representative of systemic inflammation and a powerful factor for predicting the life function and clinical outcome of patients with cancer cachexia.

Cross-Linkable Polyion Complex Micelles from Polypept(o)ide-Based ABC-Triblock Copolymers for siRNA Delivery.

ABC-type triblock copolymers are a rising platform especially for oligonucleotide delivery as they offer an additional functionality besides the anyhow needed functions of shielding and complexation. The authors present a polypept(o)ide-based triblock copolymer synthesized by amine-initiated ring-opening polymerization (ROP) of N-carboxyanhydrides (NCAs), comprising a shielding block A of polysarcosine (pSar), a poly(S-ethylsulfonyl-l-cystein) (pCys(SO2 Et)) block B for bioreversible and chemo-selective cross-linking and a poly(l-lysine) (pLys) block C for complexation to construct polyion complex (PIC) micelles as vehicle for small interfering RNA (siRNA) delivery. The self-assembly behavior of ABC-type triblocks is investigated to derive correlations between block lengths of the polymer and PIC micelle structure, showing an enormous effect of the ß-sheet forming pCys(SO2 Et) block. Moreover, the block enables the introduction of disulfide cross-links by reaction with multifunctional thiols to increase stability against dilution. The right content of the additional block leads to well-defined cross-linked 50-60 nm PIC micelles purified from production impurities and determinable siRNA loading. These PIC micelles can deliver functional siRNA into Neuro2A and KB cells evaluated by cellular uptake and specific gene knockdown assays.

A1 astrocytes contribute to murine depression-like behavior and cognitive dysfunction, which can be alleviated by IL-10 or fluorocitrate treatment.

BACKGROUND: Astrocytes are crucial regulators in the central nervous system. Abnormal activation of astrocytes contributes to some behavior deficits. However, mechanisms underlying the effects remain unclear. Here, we studied the activation of A1 astrocytes and their contribution to murine behavior deficits. METHODS: A1 astrocytes were induced by treatment with lipopolysaccharide (LPS) in vitro. The functional phenotype of astrocytes was determined by quantitative RT-PCR, ELISA, and immunohistochemistry. To assess the role of A1 astrocytes in vivo, mice were injected intraperitoneally with LPS. Then, murine behaviors were tested, and the hippocampus and cortex were analyzed by quantitative RT-PCR, ELISA, and immunohistochemistry. The function of IL-10 and fluorocitrate on A1 astrocyte activation was also examined. RESULTS: Our results show that astrocytes isolated from B6.129S6-Il10tm1Flv/J homozygotes (IL-10tm1/tm1) were prone to characteristics of A1 reactive astrocytes. Compared with their wild-type counterparts, IL-10tm1/tm1 astrocytes exhibited higher expression of glial fibrillary acidic protein (GFAP). Whether or not they were stimulated with LPS, IL-10tm1/tm1 astrocytes exhibited enhanced expression of A1-specific transcripts and proinflammatory factors IL-1ß, IL-6, and TNFα. In addition, IL-10tm1/tm1 astrocytes demonstrated hyperphosphorylation of STAT3. Moreover, astrocytes from IL-10tm1/tm1 mice showed attenuated phagocytic ability and were neurotoxic. IL-10tm1/tm1 mice demonstrated increased immobility time in the forced swim test and defective learning and memory behavior in the Morris water maze test. Moreover, enhanced neuroinflammation was found in the hippocampus and cortex of IL-10tm1/tm1 mice, accompanying with more GFAP-positive astrocytes and severe neuron loss in the hippocampus. Pretreatment IL-10tm1/tm1 mice with IL-10 or fluorocitrate decreased the expression of proinflammatory factors and A1-specific transcripts in the hippocampus and cortex, and then alleviated LPS-induced depressive-like behavior. CONCLUSION: These results demonstrate that astrocytes isolated from B6.129S6-Il10tm1Flv/J homozygotes are prone to A1 phenotype and contribute to the depression-like behavior and memory deficits. Inhibiting A1 astrocyte activation may be an attractive therapeutic strategy in some neurodegenerative diseases.