Macrophage-mediated immune response aggravates hearing disfunction caused by the disorder of mitochondrial dynamics in cochlear hair cells.

Mitochondrial dynamics is essential for maintaining the physiological function of the mitochondrial network, and its disorders lead to a variety of diseases. Our previous study identified mitochondrial dynamics controlled anti-tumor immune responses and anxiety symptoms. However, how mitochondrial dynamics affects auditory function in the inner ear remains unclear. Here, we show that the deficiency of FAM73a or FAM73b, two mitochondrial outer membrane proteins that mediate mitochondrial fusion, leads to outer hair cells (HCs) damage and progressive hearing loss in FVB/N mice. Abnormal mitochondrial fusion causes elevated oxidative stress and apoptosis of HCs in the early stage. Thereafter, the activation of macrophages and CD4+ T cell is found in the mutant mice with the increased expression of the inflammatory cytokines IL-12 and IFN-γ compared with control mice. Strikingly, a dramatically decreased number of macrophages by Clophosome®-A-Clodronate Liposomes treatment alleviates the hearing loss of mutant mice. Collectively, our finding highlights that FAM73a or FAM73b deficiency affects HCs survival by disturbing the mitochondrial function, and the subsequent immune response in the cochleae worsens the damage of HCs.

Development of a pre-column derivatization ultra-high-performance liquid chromatography method for polysaccharide and monosaccharide quantification in Lycium barbarum.

Given the limited specificity and accuracy observed in the current official colorimetric quantification of polysaccharide in Lycium barbarum, our study aims to establish a novel, specific, accurate, and economic pre-column derivatization ultra-high-performance liquid chromatography (UHPLC) method for determining the monosaccharide and polysaccharide content in L. barbarum. The optimization of extraction, hydrolysis, and derivatization (using 1-phenyl-3-methyl-5-pyrazolone) processes for polysaccharide from L. barbarum was conducted initially, followed by separation of nine monosaccharides within 20 min using UHPLC with a C18 column. Subsequently, a novel method known as quantitative analysis of multiple components by single marker was developed, utilizing either additive 2-deoxy-D-ribose or any monosaccharide present in the sample as a single reference standard to simultaneously detect the contents of polysaccharide and nine monosaccharides in L. barbarum. To validate the accuracy of the established method, the quantitative results of our approach were compared to both external and internal standard method methods. The minimal relative errors in the quantitative determination of monosaccharides among the three methods confirmed the dependability of the method. By analyzing 20 batches of L. barbarum samples, D-galacturonic acid exhibited the highest content and the polysaccharide levels ranged from 3.02 to 13.04 mg/g. All data implied the specificity and accuracy of the method.

A subunit vaccine based on Brucella rBP26 induces Th1 immune responses and M1 macrophage activation.

Brucellosis is a global zoonotic infection caused by Brucella bacteria, which poses a significant burden on society. While transmission prevention is currently the most effective method, the absence of a licenced vaccine for humans necessitates the urgent development of a safe and effective vaccine. Recombinant protein-based subunit vaccines are considered promising options, and in this study, the Brucella BP26 protein is expressed using prokaryotic expression systems. The immune responses are evaluated using the well-established adjuvant CpG-ODN. The results demonstrate that rBP26 supplemented with a CpG adjuvant induces M1 macrophage polarization and stimulates cellular immune responses mediated by Th1 cells and CD8 + T cells. Additionally, it generates high levels of rBP26-specific antibodies in immunized mice. Furthermore, rBP26 immunization activates, proliferates, and produces cytokines in T lymphocytes while also maintaining immune memory for an extended period of time. These findings shed light on the potential biological function of rBP26, which is crucial for understanding brucellosis pathogenesis. Moreover, rBP26 holds promise as an effective subunit vaccine candidate for use in endemic areas.

Integrating untargeted and targeted LC-MS-based metabolomics to identify the serum metabolite biomarkers for tuberculosis.

Given the limitations of untargeted metabolomics in precise metabolite quantification, our current research employed a novel approach by integrating untargeted and targeted metabolomics utilizing ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) to analyze the metabolic profile and potential biomarkers for tuberculosis (TB). A cohort of 36 TB patients and 36 healthy controls (HC) was enlisted to obtain serum samples. Multivariate pattern recognition and univariate statistical analysis were employed to screen and elucidate the differential metabolites, whereas dot plots and receiver operating characteristic (ROC) curves were established for the identification of potential biomarkers of TB. The results indicated a distinct differentiation between the two groups, identifying 99 metabolites associated with five primary metabolic pathways in relation to TB. Of these, 19 metabolites exhibited high levels of sensitivity and specificity, as evidenced by the area under curve values approaching 1. Following targeted quantitative analysis, three potential metabolites, namely, L-asparagine, L-glutamic acid, and arachidonic acid, were demonstrated excellent discriminatory ability as evidenced by the results of the ROC curve, dot plots, and random forest model. Particularly noteworthy was the enhanced diagnostic efficacy of the combination of these three metabolites compared to singular biomarkers, suggesting their potential utility as serum biomarkers for TB diagnosis.

Serum metabolic profile evidence for relationship between schizophrenia and depression: An untargeted metabolomics.

Given the genetic and clinical overlap observed between schizophrenia and depression, the present study was to identify the similarities and differences in serum metabolic profiles between patients with schizophrenia and depression. Global metabolomics research methods based on UHPLC-QTOF-MS/MS were performed. A total of 113 and 118 differential metabolites were screened and identified in depression and schizophrenia groups, respectively, as compared to health control; among those, 94 differential metabolites were shared by both. Pathway analysis indicated arginine and proline metabolism, alanine, aspartate, and glutamate metabolism were two significant metabolic pathways both in depression and schizophrenia groups as compared with health control groups, respectively. Similarly, 77 differential metabolites were identified between depression and schizophrenia groups, in which, serum N-acetylglutamine and isovalerylglycine levels showed significant differences between patients with depression and schizophrenia with p values less than 0.001 and without significant outliers. Sphingolipid metabolism was identified as a significant metabolic pathway distinguishing between depression and schizophrenia groups based on pathway analysis. Conclusively, common alterations in arginine and proline metabolism, alanine, aspartate, and glutamate metabolism were observed in patients with schizophrenia and depression; whereas differences in serum N-acetylglutamine and isovalerylglycine levels as well as sphingolipid metabolism were discovered between the two categories of patients.

Pharmacokinetic, Tissue Distribution, Metabolite, and Toxicity Evaluation of the Matrine Derivative, (6aS, 10S, 11aR, 11bR, 11cS)-10-Methylaminododecahydro-3a, 7a-Diaza-benzo (de) Anthracene-8-thione.

MASM, a structurally modified derivative of matrine, exhibits superior efficacy in reducing inflammation and liver injury in rats when compared to matrine. This study aims to investigate the pharmacokinetic profile and acute toxicity of MASM. Pharmacokinetic results revealed that MASM exhibited rapid absorption, with a Tmax ranging from 0.21 ± 0.04 h to 1.31 ± 0.53 h, and was eliminated slowly, with a t1/2 of approximately 10 h regardless of the route of administration (intravenous, intraperitoneal, or intragastric). The absolute intragastric bioavailability of MASM in rats was determined to be 44.50%, which was significantly higher than that of matrine (18.5%). MASM was detected in all rat tissues including the brain, and through the utilization of stable isotope-labeled compounds and standard references, ten metabolites of MASM, namely sophocarpine, oxysophocarpine, and oxymatrine, were tentatively identified. The LD50 of MASM in mice was determined to be 94.25 mg/kg, surpassing that of matrine (83.21 mg/kg) based on acute toxicity results. Histopathological and biochemical analysis indicated no significant alterations in the primary organs of the low- to medium-dosage groups of MASM. These findings provide valuable insights into the efficacy and toxicity profile of MASM.

Serum exosomal microRNA transcriptome profiling in subacute spinal cord injured rats.

MicroRNAs (miRNAs) are involved in a series of pathology of spinal cord injury (SCI). Although, locally expressed miRNAs have advantages in studying the pathological mechanism, they cannot be used as biomarkers. The "free circulation" miRNAs can be used as biomarkers, but they have low concentration and poor stability in body fluids. Exosomal miRNAs in body fluids have many advantages comparing with free miRNAs. Therefore, we hypothesized that the specific miRNAs in the central nervous system might be transported to the peripheral circulation and concentrated in exosomes after injury. Using next-generation sequencing, miRNA profiles in serum exosomes of sham and subactue SCI rats were analyzed. The results showed that SCI can lead to changes of serum exosomal miRNAs. These changed miRNAs and their associated signaling pathways may explain the pathological mechanism of suacute SCI. More importantly, we found some valuable serum exosomal miRNAs for diagnosis and prognosis of SCI.

Serum exosomal microRNA transcriptome profiling in subacute spinal cord injured rats.

MicroRNAs (miRNAs) are involved in a series of pathology of spinal cord injury (SCI). Although, locally expressed miRNAs have advantages in studying the pathological mechanism, they cannot be used as biomarkers. The "free circulation" miRNAs can be used as biomarkers, but they have low concentration and poor stability in body fluids. Exosomal miRNAs in body fluids have many advantages comparing with free miRNAs. Therefore, we hypothesized that the specific miRNAs in the central nervous system might be transported to the peripheral circulation and concentrated in exosomes after injury. Using next-generation sequencing, miRNA profiles in serum exosomes of sham and subactue SCI rats were analyzed. The results showed that SCI can lead to changes of serum exosomal miRNAs. These changed miRNAs and their associated signaling pathways may explain the pathological mechanism of suacute SCI. More importantly, we found some valuable serum exosomal miRNAs for diagnosis and prognosis of SCI.

CRID3, a blocker of apoptosis associated speck like protein containing a card, ameliorates murine spinal cord injury by improving local immune microenvironment.

BACKGROUND: After spinal cord injury (SCI), destructive immune cell subsets are dominant in the local microenvironment, which are the important mechanism of injury. Studies have shown that inflammasomes play an important role in the inflammation following SCI, and apoptosis-associated speck-like protein containing a card (ASC) is the adaptor protein shared by inflammasomes. Therefore, we speculated that inhibiting ASC may improve the local microenvironment of injured spinal cord. Here, CRID3, a blocker of ASC oligomerization, was used to study its effect on the local microenvironment and the possible role in neuroprotection following SCI. METHODS: Murine SCI model was created using an Infinite Horizon impactor at T9 vertebral level with a force of 50 kdynes and CRID3 (50 mg/kg) was intraperitoneally injected following injury. ASC and its downstream molecules in inflammasome signaling pathway were measured by western blot. The immune cell subsets were detected by immunohistofluorescence (IHF) and flow cytometry (FCM). The spinal cord fibrosis area, neuron survival, myelin preservation, and functional recovery were assessed. RESULTS: Following SCI, CRID3 administration inhibited inflammasome-related ASC and caspase-1, IL-1ß, and IL-18 activation, which consequently suppressed M1 microglia, Th1 and Th1Th17 differentiation, and increased M2 microglia and Th2 differentiation. Accordingly, the improved histology and behavior have also been found. CONCLUSIONS: CRID3 may ameliorate murine SCI by inhibiting inflammasome activation, reducing proinflammatory factor production, restoring immune cell subset balance, and improving local immune microenvironment, and early administration may be a promising therapeutic strategy for SCI.

Transcriptome profile of rat genes in bone marrow-derived macrophages at different activation statuses by RNA-sequencing.

The underlying mechanisms of macrophage polarization have been detected by genome-wide transcriptome analysis in a variety of mammals. However, the transcriptome profile of rat genes in bone marrow-derived macrophages (BMM) at different activation statuses has not been reported. Therefore, we performed RNA-Sequencing to identify gene expression signatures of rat BMM polarized in vitro with different stimuli. The differentially expressed genes (DEGs) among unactivated (M0), classically activated pro-inflammatory (M1), and alternatively activated anti-inflammatory macrophages (M2) were analyzed by using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. In this study, not only we have identified the changes of global gene expression in rat M0, M1 and M2, but we have also made clear systematically the key genes and signaling pathways in the differentiation process of M0 to M1 and M2. These will provide a foundation for future researches of macrophage polarization.

NLRP2 negatively regulates antiviral immunity by interacting with TBK1.

Nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are intracellular pattern recognition receptors (PRRs) that regulate a variety of inflammatory and host defense responses. Unlike the well-established NLRs, the roles of NLRP2 are controversial and poorly defined. Here, we report that NLRP2 acts as a negative regulator of TANK-binding kinase 1 (TBK1)-mediated type I interferon (IFN) signaling. Mechanistically, NLRP2 interacted directly with TBK1, and this binding disrupted the interaction of TBK1 and interferon regulatory factor 3 (IRF3), which interfered with TBK1-induced IRF3 phosphorylation. IFNs induce a series of proteins that have well-known antiviral or immune-regulatory functions, and tight control of the IFN signaling cascade is critical for limiting tissue damage and preventing autoimmunity. Our studies indicate that the NLRP2-TBK1 axis may serve as an additional signaling cascade to maintain immune homeostasis in response to viral infection.

MiR-129-3p favors intracellular BCG survival in RAW264.7 cells by inhibiting autophagy via Atg4b.

Autophagy plays an important role in the fight against Mycobacterium tuberculosis infection. Massive researches proved that miRNAs could be the regulators of autophagy, which implied miRNAs could favor MTB invasion or latent infection. In our study, multiple bioinformatics databases and software were used to seek and lock the miRNAs associating with regulation of autophagy. Notably, a novel miR-129-3p was found and its target gene Atg4b showed grand potential in mediation of autophagy. Moreover, BCG infection triggered miR-129-3p overexpression in RAW264.7 cells. Up-regulation of miR-129-3p decreased mRNA or protein level of Atg4b and resulted in the inhibition of autophagy. The antagomir of miR-129-3p had the opposite impact. The LC3 puncta formation in RAW264.7 cells were also affected after transfection of miR-129-3p mimic or antagomir. The mRFP-GFP-LC3 analysis indicated that mimic of miR-129-3p impaired autophagic flux while antagomir improved autophagy. The CFU assay results showed that miR-129-3p promoted the intracellular survival of BCG in macrophages. Consequently, these data suggested that miR-129-3p could favor MTB survival by inhibiting autophagy via Atg4b.

Screening of reference genes and quantitative real-time PCR detection and verification in Dermatophagoides farinae under temperature stress.

Dermatophagoides farinae is an important source of indoor allergens that shows strong tolerance to external temperatures. However, the regularity and mechanism of tolerance are still unclear. Based on our previous RNA-seq and annotation of D. farinae under temperature stress, it is planned to identify differentially expressed genes (DEGs) involved in the temperature stress response by quantitative real-time PCR (qRT-PCR). However, the lack of reference genes directly limited the detection and confirmation of DEGs. Accordingly, in this study, we have selected six candidates as reference genes in D. farinae: 60S RP L11, 60S RP L21, α tubulin, GAPDH, Der f Mal f 6, and calreticulin, and evaluated their expression stabilities as affected by heat and cold stresses, using geNorm, NormFinder, BestKeeper, comparative ΔCt and RefFinder methods. Then the expression level of 15 DEGs were detected and verified. geNorm analysis showed that α tubulin and calreticulin were the most stable reference genes under heat stress and cold stress of D. farinae. Similar evaluation results were obtained by NormFinder and BestKeeper, in which 60S RP L21 and α tubulin were the most stable reference genes. By comparative ΔCt method and a comprehensive evaluation of RefFinder, α tubulin was identified as the most ideal reference gene of D. farinae under heat and cold stresses. Furthermore, qRT-PCR detection results of 15 DEGs were almost identical to the RNA-seq results, indicating that α tubulin is stable as a reference gene. This study provided technical support for DEGs expression studies in D. farinae using qRT-PCR.

Increased ceruloplasmin expression caused by infiltrated leukocytes, activated microglia, and astrocytes in injured female rat spinal cords.

Ceruloplasmin (Cp), an enzyme containing six copper atoms, has important roles in iron homeostasis and antioxidant defense. After spinal cord injury (SCI), the cellular components in the local microenvironment are very complex and include functional changes of resident cells and the infiltration of leukocytes. It has been confirmed that Cp is elevated primarily in astrocytes and to a lesser extent in macrophages following SCI in mice. However, its expression in other cell types is still not very clear. In this manuscript, we provide a sensible extension of these findings by examining this system within a female Sprague-Dawley rat model and expanding the scope of inquiry to include additional cell types. Quantitative reverse transcription polymerase chain reaction and Western blot analysis revealed that the Cp mRNA and protein in SCI tissue homogenates were quite consistent with prior publications. However, we observed that Cp was expressed not only in GFAP+ astrocytes (consistent with prior reports) but also in CD11b+ microglia, CNPase+ oligodendrocytes, NeuN+ neurons, CD45+ leukocytes, and CD68+ activated microglia/macrophages. Quantitative analysis proved that infiltrated leukocytes, activated microglia/macrophages, and astrocytes should be the major sources of increased Cp.

Immunologic properties and therapeutic efficacy of a multivalent epitope-based vaccine against four Helicobacter pylori adhesins (urease, Lpp20, HpaA, and CagL) in Mongolian gerbils.

BACKGROUND: Therapeutic vaccination is a desirable alternative for controlling Helicobacter pylori (H. pylori) infection. Attachment to the gastric mucosa is the first step in establishing bacterial colonization, and adhesins, which are on the surface of H. pylori, play a pivotal role in binding to human gastric mucosa. MATERIALS AND METHODS: In the present study, we constructed a multivalent epitope-based vaccine named CFAdE with seven carefully selected antigenic fragments from four H. pylori adhesins (urease, Lpp20, HpaA and CagL). The specificity, immunogenicity and ability to produce neutralizing antibodies of CFAdE were evaluated in BALB/c mice. After that, its therapeutic efficacy and protective immune mechanisms were explored in H. pylori-infected Mongolian gerbils. RESULTS: The results indicated that CFAdE could induce comparatively high levels of specific antibodies against urease, Lpp20, HpaA and CagL. Additionally, oral therapeutic immunization with CFAdE plus polysaccharide adjuvant (PA) significantly decreased H. pylori colonization compared with oral immunization with urease plus PA, and the protection was correlated with IgG and sIgA antibody and antigen-specific CD4+ T cells. CONCLUSIONS: This study indicated that the multivalent epitope-based vaccine, which targeted multiple adhesins in adherence of H. pylori to the gastric mucosa, is more effective than the univalent vaccine targeting urease only. This multivalent epitope-based vaccine may be a promising therapeutic candidate vaccine against H. pylori infection.

Baculovirus-mediated endostatin and angiostatin activation of autophagy through the AMPK/AKT/mTOR pathway inhibits angiogenesis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a highly vascularized carcinoma, and targeting its neovascularization represents an effective therapeutic approach. Our previous study demonstrated that the baculovirus-mediated endostatin and angiostatin fusion protein (BDS-hEA) effectively inhibits the angiogenesis of vascular endothelial cells and the growth of HCC tumors. However, the mechanism underlying its anti-angiogenic effect remains unclear. Increasing evidence suggests that autophagy has a significant impact on the function of vascular endothelial cells and response to cancer therapy. Hence, the objective of this research was to investigate the correlation between BDS-hEA-induced angiogenesis inhibition and autophagy, along with potential regulatory mechanisms. Our results demonstrated that BDS-hEA induced autophagy in EA.hy926 cells, as evidenced by the increasing number of autophagosomes and reactive oxygen species, accompanied by an upregulation of Beclin-1, LC3-II/LC3-I, and p62 protein expression. Suppression of autophagy using 3-methyladenine attenuated the functions of BDS-hEA-induced EA.hy926 cells, including the viability, proliferation, invasion, migration, and angiogenesis. Moreover, BDS-hEA induced autophagy by downregulating the expression of CD31, VEGF, and VEGFR2, as well as phosphorylated protein kinase B (p-AKT) and phosphorylated mammalian target of rapamycin (p-mTOR), while concurrently upregulating phosphorylated AMP-activated protein kinase (p-AMPK). The in vivo results further indicated that inhibition of autophagy by chloroquine significantly impeded the ability of BDS-hEA to suppress HCC tumor growth in mice. Mechanistically, BDS-hEA prominently facilitated autophagic apoptosis in tumor tissues and decreased the levels of ki67, CD31, VEGF, MMP-9, p-AKT, and p-mTOR while simultaneously enhancing the p-AMPK expression. In conclusion, our findings suggest that BDS-hEA induces autophagy as a cytotoxic response by modulating the AMPK/AKT/mTOR signaling pathway, thereby exerting anti-angiogenic effects against HCC.

Serum metabolomics reveals the metabolic profile and potential biomarkers of ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease that significantly impairs physical function in young individuals. However, the identification of radiographic changes in AS is frequently delayed, and the diagnostic efficacy of biomarkers like HLA-B27 remains moderately effective, with unsatisfactory sensitivity and specificity. In contrast to existing literature, our current experiment utilized a larger sample size and employed both untargeted and targeted UHPLC-QTOF-MS/MS based metabolomics to identify the metabolite profile and potential biomarkers of AS. The results indicated a notable divergence between the two groups, and a total of 170 different metabolites were identified, which were associated with the 6 primary metabolic pathways exhibiting a correlation with AS. Among these, 26 metabolites exhibited high sensitivity and specificity with area under curve (AUC) values greater than 0.8. Subsequent targeted quantitative analysis discovered 3 metabolites, namely 3-amino-2-piperidone, hypoxanthine and octadecylamine, exhibiting excellent distinguishing ability based on the results of the ROC curve and the Random Forest model, thus qualifying as potential biomarkers for AS. Summarily, our untargeted and targeted metabolomics investigation offers novel and precise insights into potential biomarkers for AS, potentially enhancing diagnostic capabilities and furthering the comprehension of the condition's pathophysiology.

Genetic deletion of the apoptosis associated speck like protein containing a card in LysM+ macrophages attenuates spinal cord injury by regulating M1/M2 polarization through ASC-dependent inflammasome signaling axis.

Apoptosis associated speck like protein containing a card (ASC), the key adaptor protein of the assembly and activation of canonical inflammasomes, has been found to play a significant role in neuroinflammation after spinal cord injury (SCI). The previous studies indicated that widely block or knockout ASC can ameliorate SCI. However, ASC is ubiquitously expressed in infiltrated macrophages and local microglia, so further exploration is needed on which type of cell playing the key role. In this study, using the LysMcre;Ascflox/flox mice with macrophage-specifc ASC conditional knockout (CKO) and contusive SCI model, we focus on evaluating the specific role of ASC in lysozyme 2 (LysM)+ myeloid cells (mainly infiltrated macrophages) in this pathology. The results revealed that macrophage-specifc Asc CKO exhibited the follow effects: (1) A significant reduction in the numbers of infiltrated macrophages in the all phases of SCI, and activated microglia in the acute and subacute phases. (2) A significant reduction in ASC, caspase-1, interleukin (IL)-1ß, and IL-18 compared to control mice. (3) In the acute and subacute phases of SCI, M1 subset differentiation was inhibited, and M2 differentiation was increased. (4) Histology and hindlimb motor recoveries were improved. In conclusion, this study elucidates that macrophage-specific ASC CKO can improve nerve function recovery after SCI by regulating M1/M2 polarization through inhibiting ASC-dependent inflammasome signaling axis. This indicates that ASC in peripheral infiltrated macrophages may play an important role in SCI pathology, at least in mice, could be a potential target for treatment.

A comparative UHPLC-QTOF-MS/MS-based metabolomics approach reveals the metabolite profiling of wolfberry sourced from different geographical origins.

Wolfberry, known as Goji berry, is the fruit of Lycium barbarum L. (LB). As a famous functional food and TCM, the cost and efficacy of LB are closely linked to its geographical origin. The present study aimed to establish an effective method for distinguishing LB from different geographical origins. By employing UHPLC-QTOF-MS/MS combined with multivariate analysis, the metabolite profiling of LB (199 batches) obtained from Ningxia, Gansu, Qinghai, and Xinjiang, was evaluated. The results demonstrated that the method effectively distinguished LB from the four regions, with a total of 148 different metabolites being detected. Subsequent assessment using heat maps, Venn analysis, receiver operating characteristics curves and dot plots revealed 21 of these metabolites exhibited exceptional sensitivity and specificity, with under-curve values approaching 1, thus indicating their potential as biomarkers for LB. These findings strongly support the suitability of UHPLC-QTOF-MS/MS-based metabolomics as an effective approach to identify the source of LB.

Exosomes derived from vMIP-II-Lamp2b gene-modified M2 cells provide neuroprotection by targeting the injured spinal cord, inhibiting chemokine signals and modulating microglia/macrophage polarization in mice.

Inflammation is one of the key injury factors for spinal cord injury (SCI). Exosomes (Exos) derived from M2 macrophages have been shown to inhibit inflammation and be beneficial in SCI animal models. However, lacking targetability restricts their application prospects. Considering that chemokine receptors increase dramatically after SCI, viral macrophage inflammatory protein II (vMIP-II) is a broad-spectrum chemokine receptor binding peptide, and lysosomal associated membrane protein 2b (Lamp2b) is the key membrane component of Exos, we speculated that vMIP-II-Lamp2b gene-modified M2 macrophage-derived Exos (vMIP-II-Lamp2b-M2-Exo) not only have anti-inflammatory properties, but also can target the injured area by vMIP-II. In this study, using a murine contusive SCI model, we revealed that vMIP-II-Lamp2b-M2-Exo could target the chemokine receptors which highly expressed in the injured spinal cords, inhibit some key chemokine receptor signaling pathways (such as MAPK and Akt), further inhibit proinflammatory factors (such as IL-1ß, IL-6, IL-17, IL-18, TNF-α, and iNOS), and promote anti-inflammatory factors (such as IL-4 and Arg1) productions, and the transformation of microglia/macrophages from M1 into M2. Moreover, the improved histological and functional recoveries were also found. Collectively, our results suggest that vMIP-II-Lamp2b-M2-Exo may provide neuroprotection by targeting the injured spinal cord, inhibiting some chemokine signals, reducing proinflammatory factor production and modulating microglia/macrophage polarization.