Subregions of the fusiform gyrus are differentially involved in the attentional mechanism supporting visual mental imagery in depression.

BACKGROUND: Impaired visual mental imagery is an important symptom of depression and has gradually become an intervention target for cognitive behavioral therapy. METHODS: Our study involved a total of 25 healthy controls (HC) and 23 individuals with moderate depressive symptoms (MD). This study explored the attentional mechanism supporting visual mental imagery impairments in depression using the Vividness of Visual Imagery Questionnaire (VVIQ), attentional network test (ANT), and resting-state functional magnetic resonance imaging (rs-fMRI). The intrinsic activity of attention-related regions relative to those supporting visual mental imagery was identified in depression patients. In addition, a meta-analysis was used to describe the cognitive function related to this intrinsic activity. RESULTS: The global correlation (GCOR) of the right anterior fusiform gyrus (FG) was decreased in depression patients. Attention-related areas were concentrated in the right posterior FG; the anterior and posterior functional connectivity (FC) of the FG was decreased in depression patients. Graph theoretic analysis showed that the degree of the right anterior FG was decreased, the degree of the anterior insula was increased, and the negative connection between these two regions was strengthened in depression patients. In addition, the degree of the right anterior FG, the FC between the subregions of the right FG, and the FC between the right anterior FG and insula were correlated with VVIQ scores; however, this correlation was not significant in depression patients. The meta-analysis suggested that the changes in the anterior FG in depressed patients may stem from difficulties of semantic memory retrieval. CONCLUSION: The changed intrinsic activity of subregions of the FG relative to the semantic memory retrieval may be associated with visual mental imagery impairments in depression.

Perceived stress and brain connectivity in subthreshold depression: Insights from eyes-closed and eyes-open states.

Perceived stress is an acknowledged risk factor for subthreshold depression (StD), and fluctuations in perceived stress are thought to disrupt the harmony of brain networks essential for emotional and cognitive functioning. This study aimed to elucidate the relationship between eye-open (EO) and eye-closed (EC) states, perceived stress, and StD. We recruited 27 individuals with StD and 33 healthy controls, collecting resting state fMRI data under both EC and EO conditions. We combined intrinsic connectivity and seed-based functional connectivity analyses to construct the functional network and explore differences between EC and EO conditions. Graph theory analysis revealed weakened connectivity strength in the right superior frontal gyrus (SFG) and right median cingulate and paracingulate gyrus (MCC) among participants with StD, suggesting an important role for these regions in the stress-related emotions dysregulation. Notably, altered SFG connectivity was observed to significantly relate to perceived stress levels in StD, and the SFG connection emerges as a neural mediator potentially influencing the relationship between perceived stress and StD. These findings highlight the role of SFG and MCC in perceived stress and suggest that understanding EC and EO states in relation to these regions is important in the neurobiological framework of StD. This may offer valuable perspectives for early prevention and intervention strategies in mental health disorders.

Inhibition of the interaction between microglial adenosine 2A receptor and NLRP3 inflammasome attenuates neuroinflammation posttraumatic brain injury.

AIMS: Adenosine 2A receptor (A2A R) is widely expressed in the brain and plays important roles in neuroinflammation, and the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome is a crucial component of the innate immune system while the regulation of A2A R on it in the central nervous system (CNS) has not been clarified. METHODS: The effects of microglial A2A R on NLRP3 inflammasome assembly and activation were investigated in wild-type, A2A R- or NLRP3-knockout primary microglia with pharmacological treatment. Microglial A2A R or NLRP3 conditional knockout mice were used to interrogate the effects of this regulation on neuroinflammation posttraumatic brain injury (TBI). RESULTS: We found that A2A R directly interacted with NLRP3 and facilitated NLRP3 inflammasome assembly and activation in primary microglia while having no effects on mRNA levels of inflammasome components. Inhibition of the interaction via A2A R agonist or knockout attenuated inflammasome assembly and activation in vitro. In the TBI model, microglial A2A R and NLRP3 were co-expressed at high levels in microglia next to the peri-injured cortex, and abrogating of this interaction by microglial NLRP3 or A2A R conditional knockout attenuated the neurological deficits and neuropathology post-TBI via reducing the NLRP3 inflammasome activation. CONCLUSION: Our results demonstrated that inhibition of the interaction between A2A R and NLRP3 in microglia could mitigate the NLRP3 inflammasome assembly and activation and ameliorate the neuroinflammation post-TBI. It provides new insights into the effects of A2A R on neuroinflammation regulation post-TBI and offers a potential target for the treatment of NLRP3 inflammasome-related CNS diseases.

Molecular characterization and functional study of a galectin-9 from a teleost fish, Boleophthalmus pectinirostris.

Galectin-9, a tandem-repeat galectin, plays an important role in the regulation of innate immune response against various microbial infections. Here, galectin-9 from mudskipper (Boleophthalmus pectinirostris) was identified and named as BpGal-9. Putative BpGal-9 contains two conserved carbohydrate recognition domains (CRDs), one CRD within N-terminal (N-CRD) and the other one within C-terminal (C-CRD). Multi-alignment analysis indicated that BpGal-9 shared the highest amino acid sequence identity of 64.3 % with that of Southern platyfish (Xiphophorus maculatus). Phylogenetic analysis showed that BpGal-9 grouped tightly with other teleosts galectin-9 and was most closely related to that of Southern platyfish. BpGal-9 transcripts were more abundant in the intestine, and its expression upregulated significantly in the intestine, kidney, spleen, gills, and skin after Edwardsiella tarda infection. Meanwhile, BpGal-9 expression significantly increased in hemocytes and serum of mudskipper infected by E. tarda. The recombinant BpGal-9 (rBpGal-9) and rBpGal-9C-CRD could agglutinate all tested bacteria, whereas rBpGal-9N-CRD could only agglutinate three kinds of bacteria. When targeting the same bacteria, rBpGal-9 showed stronger agglutinating activities than rBpGal-9C-CRD or rBpGal-9N-CRD. In addition, the induction effect of three recombinant proteins on the mRNA expression of anti-inflammatory cytokines (BpIL-10 and BpTGF-ß) was better than that on the pro-inflammatory cytokines (BpIL-1ß and BpTNF-α). Our result suggested that the N-CRD and C-CRD of galectin-9 contribute differently to its multiple functions in innate immunity in teleosts.

[Correlation of anti-phosphatidylserine/prothrombin antibodies with unexplained recurrent miscarriages].

OBJECTIVE: To investigate whether anti-phosphatidylserine/prothrombin antibodies and its IgG or IgM subtypes were correlated with unexplained recurrent miscarriages. METHODS: In our a single-center retrospective study, 283 patients with at least one unexplained miscarriage who visited the Third Hospital of Peking University between January 2021 and August 2023, aged between 18-40 years, and tested for anti-phosphatidylserine/prothrombin antibodies IgG or IgM subtypes, were included. The patients with either positive IgG or IgM anti-phosphatidylserine/prothrombin antibody were regarded as positive for anti-phosphatidylserine/prothrombin antibody. SPSS 26.0 software was used for statistical analysis. Chi-square test and Logistic regression analysis were used to study the correlation of anti-phosphatidylserine/prothrombin antibodies and its IgG or IgM subtypes with unexplained recurrent miscarriages. And the diagnostic sensitivity, specificity, the positive predictive value, the negative predictive value of anti-phosphatidylserine/prothrombin antibodies and its IgG or IgM subtypes in unexplained miscarriages was calculated with four-fold table. RESULTS: Chi-square analysis showed that anti-phosphatidylserine/prothrombin antibodies and its IgM subtypes were correlated with recurrent miscarriages (both P < 0.05), while the IgG subtype was not correlated with recurrent miscarriages (P>0.05). After adjusting with anticardiolipin antibodies, anti-ß2 glycoprotein antibodies, lupus anticoagulants, antinuclear antibodies, and age by Logistic regression analysis, anti-phosphatidylserine/prothrombin antibodies were correlated with unexplained recurrent miscarriages (OR=2.084, 95%CI 1.045-4.155, P < 0.05), and anti-phosphatidylserine/prothrombin antibody IgM subtypes were correlated with unexplained recurrent miscarriages (OR=2.368, 95%CI 1.187-4.722, P < 0.05).The sensitivity of anti-phosphatidylserine/prothrombin antibody in recurrent miscarriage was 65.43%, the specificity was 48.51%, the positive predictive value was 33.76%, and the negative predictive value was 77.78%. In the patients with recurrent miscarriages with negative classical antiphospholipid antibodies, the sensitivity of anti-phosphatidylserine/prothrombin antibody was 59.09%, the specificity was 63.23%, the positive predictive value was 40.63%, and the negative predictive value was 78.40%. The sensitivity of the anti-phosphatidylserine/prothrombin antibody IgM subtype for the diagnosis of recurrent miscarriage was 65.43%, the specificity was 50.99%, the positive predictive value was 34.87%, and the negative predictive value was 78.63%. CONCLUSION: Anti-phosphatidylserine/prothrombin antibody and IgM subtype antibody are correlated with unexplained recurrent miscarriages in patients with at least one unexplained miscarriage. Whether positive anti-phosphatidylserine/prothrombin antibody or IgM subtype could predict future unexplained recurrent miscarriages warrants a prospective study.

[Comparison of clinical and immunological characteristics between primary Sjögren's syndrome patients with positive and negative anti-SSB antibody].

OBJECTIVE: To analyze the differences of clinical manifestations and laboratory features between primary Sjögren's syndrome (pSS) patients with positive and negative anti-Sjögren's syndrome type B (SSB) antibody. METHODS: The clinical data of pSS patients hospitalized in Department of Rheumato-logy and Immunology, Peking University Third Hospital were retrospectively analyzed to investigate the differences of clinical and laboratory features between anti-SSB positive and negative groups. The t test, Mann-Whitney U test, Chi-square test and Fisher's exact probability were used for analysis. RESULTS: A total of 142 pSS patients were enrolled in this study, including 137 females and 5 males with a mean age of (54.8±13.3) years. The anti-SSB positive group included 44 patients accounting for 31.0% of the pSS patients. The anti-SSB positive pSS patients were younger at disease onset and at visit [age at visit: (50.9±14.5) years vs. (56.5±12.4) years; age at onset: (42.2±14.8) years vs. (49.5±15.3) years, P < 0.05]. The patients with anti-SSB positive more frequently presented with rash (29.5% vs. 14.3%, P < 0.05), enlargement of parotid glands (27.3% vs. 8.2%, P < 0.05), renal tubular acidosis (15.9% vs. 4.2%, P < 0.05), immune thrombocytopenia (9.1% vs. 1.0%, P < 0.05), rheumatoid factor (RF) positive (85.0% vs. 49.4%, P < 0.05), higher RF and antinuclear antibody (ANA) titers (median: 89.8 IU/mL vs. 20.5 IU/mL; median: 320 vs. 160, P < 0.05), anti-Sjögren's syndrome type A (SSA) antibody positive (97.7% vs. 64.3%, P < 0.05), elevation of γ globulin (71.4% vs. 38.5%, P < 0.05), higher levels of IgG (median: 21.0 g/L vs. 15.6 g/L, P < 0.05), higher proportions of CD3-CD19+ cells [(21.0±11.9)% vs. (13.7±9.6)%, P < 0.05] and lower proportions of CD3+ cells [(67.2±14.4)% vs. (76.6%±13.1)%, P < 0.05] than those negative. However, the anti-SSB positive group was less likely to show anti-mitochondrial antibodies (AMA)-M2 positivity (10.5% vs. 35.6%, P < 0.05). Glucocorticoids (90.9% vs. 73.5%, P < 0.05) and immunosuppressants (54.5% vs. 36.7%, P < 0.05) were more frequently used in anti-SSB positive pSS patients than those negative. CONCLUSION: The anti-SSB positive pSS patients were younger at disease onset while more frequently presenting with various symptoms, higher levels of other antibodies and activation of B cells than those negative. Glucocorticoids and immunosuppressants were more frequently used, indicating that anti-SSB positive group presented with a more severe clinal phenotype.

Corrigendum: Nitazoxanide, an antiprotozoal drug, reduces bone loss in ovariectomized mice by inhibition of RANKL-induced osteoclastogenesis.

[This corrects the article DOI: 10.3389/fphar.2021.781640.].

Molecular characterization and antimicrobial activity of NK-lysin in black scraper (Thamnaconus modestus).

NK-lysin (NKL) is a positively charged antimicrobial peptide with broad-spectrum bactericidal activities. In this study, the cDNA sequence of NKL (TmNKL) from black scraper (Thamnaconus modestus) was cloned, which encodes a predicted polypeptide of 150 amino acids that contains a surfactant protein B domain with three disulfide bonds. Phylogenetically, TmNKL was most closely related to its teleost counterpart from tiger puffer (Takifugu rubripes). Expression analysis demonstrated that TmNKL transcripts were constitutively expressed in all tested tissues, with the highest expression levels in the gills. Its expression was significantly upregulated in the gills, head kidney, and spleen after infection with Vibrio parahaemolyticus. A linear peptide (TmNKLP40L) and a disulfide-type peptide (TmNKLP40O) were further synthesized and results showed that disulfide bonds are not essential for bactericidal activities of TmNKL, and that both forms of TmNKL exhibited potent bactericidal activities against 4 gram- negative bacteria, including V. parahaemolyticus, V. alginolyticus, Edwardsiella tarda, and V. harveyi. Observed antimicrobial activities are likely due to the effects of TmNKLP40L and TmNKLP40O treatment on disrupting the integrity of both inner and outer membrane of V. parahaemolyticus, resulting in hydrolysis of bacterial genomic DNA. Damaged cell membranes and leakage of intracellular contents were further confirmed using scanning and transmission microscopy. Moreover, administration of 1.0 µg/g TmNKLP40L or TmNKLP40O significantly decreased bacterial load in tissues and thus, pronouncedly enhanced the survival of V. parahaemolyticus-infected fish. Overall, our results demonstrated that TmNKL is a potent innate effector and provides protective effects against bacterial infection.

Knockdown of adenosine A2A receptors in hippocampal neurons prevents post-TBI fear memory retrieval.

The formation of fear memory is crucial in emotional disorders such as PTSD and anxiety. Traumatic brain injury (TBI) can cause emotional disorders with dysregulated fear memory formation; however, their cross-interaction remains unclear and hurdled the treatment against TBI-related emotional disorders. While adenosine A2A receptor(A2AR) contributes to the physiological regulation of fear memory, this study aimed to evaluate the A2AR role and possible mechanisms in post-TBI fear memory formation using a craniocerebral trauma model, genetically modified A2AR mutant mice, and pharmacological A2AR agonist CGS21680 and antagonist ZM241385. Our finding showed (i) TBI enhanced mice freezing levels (fear memory) at seven days post-TBI; (ii) The A2AR agonist CGS21680 enhanced the post-TBI freezing levels; conversely, the A2AR antagonist ZM241385 reduced mice freezing level; further (iii) Genetic knockdown of neuronal A2AR in the hippocampal CA1, CA3, and DG regions reduced post-TBI freezing levels, while A2AR knockout in DG region yielded the most reduction in fear memory; finally, (iv) AAV-CaMKII-Cre virus-mediated DG deletion of A2AR on excitatory neurons led to a significant decreased freezing levels post-TBI. These findings indicate that brain trauma increases fear memory retrieval post-TBI, and A2AR on DG excitatory neurons plays a crucial role in this process. Importantly, inhibition of A2AR attenuates fear memory enhancement, which provides a new strategy to prevent fear memory formation/enhancement after TBI.

Molecular and functional characterization of a ladderlectin-like molecule from ayu (Plecoglossus altivelis).

Ladderlectin is a member of C-type lectins (CTLs) in teleost fish and involved in innate immune defense. In this study, ayu (Plecoglossus altivelis) ladderlecin-like (PaLL-like) sequence was cloned, which encodes a polypeptide of 172 amino acids that includes a signal peptide and characteristic C-type lectin-like domains (CTLDs). Phylogenetically, PaLL-like was most closely related to its teleost counterpart from shishamo smelt (Spirinchus lanceolatus). Expression analysis revealed a ubiquitous expression profile, with highest expression detected in liver and its expression was up-regulated following Vibiro anguillarum infection. Similar to canonical CTLs, PaLL-like exhibited carbohydrate-binidng capacities to a wide range of well-defined mono-/di-saccharides and likely confer PaLL-like the ability to agglutinate all tested bacterial, including three Gram-positive species (i.e., Listeria monocytogenes, Staphylococcus aureus and Streptococcus iniae) and eight Gram-negative species (i.e., Edwardsiella tarda, Aeromonas (A.) hydrophila, Escherichia coli, Vibrio (V.) harveyi, V. anguillarum, V. parahemolyticus, A. versoni and V. vulnificus), in a calcium-dependent manner. Further functional studies revealed that PaLL-like displayed immunomodulatory activities leading to enhanced bactericidal activity of serum, pathogen opsonization and macrophage activation with increased expression of pro-inflammatory cytokines (i.e., PaIL-1ß and PaTNF-α). Collectively, these immunomodulatory activities of PaLL-like suppressed proliferations of V. anguillarum in targeted tissued in vivo and likely contributed to the increased survival rate of infected-fish. Overall, our results demonstrated PaLL-like is a critical component of innate immunity and provides protective effects against bacterial infection.

Acute, chronic, and genotoxic studies on the protopine total alkaloids of the Macleaya cordata (willd.) R. Br. in rodents.

The protopine alkaloids are widely distributed within the opium poppy family and have a wide range of pharmacological effects. MPTA is a product of the protopine total alkaloids extracted from the Macleaya cordata (Willd.) R. Br. Previously, we reported good anti-inflammatory activity of MPTA as well as oral acute and sub-chronic toxicity studies in rats. In order to perform a systematic toxicological safety assessment of MPTA, oral acute toxicity, genotoxicity (bone marrow cell chromosome aberration test, sperm abnormality test, bone marrow cell micronucleus test, and rat teratogenicity test), and chronic toxicity in mice were performed in this study. In the oral acute toxicity test, the LD50 in ICR mice was 481.99 mg/kg, with 95% confidence limits ranging from 404.27 to 574.70 mg/kg. All three mutagenicity tests tested negative in the range of 60.25-241.00 mg/kg. The results of the teratogenicity test in rats showed no reproductive or embryonic developmental toxicity at only 7.53 mg/kg, which can be considered as a no observed effect level (NOEL) for the teratogenicity test. Therefore, MPTA is safe for use at the doses tested, but attention should be paid to the potential risk to pregnant animals and the safety evaluation and toxicity mechanisms in target animals should be further investigated.

Preclinical safety evaluation of Macleaya Cordata extract: A re-assessment of general toxicity and genotoxicity properties in rodents.

Macleaya cordata extract (MCE) is widely used for its diverse pharmacological actions and beneficial effects on farm animals. Modern pharmacological studies have shown that it has anti-inflammatory, anti-cancer, and anti-bacterial activities, and is gradually becoming a long-term additive veterinary drug used to improve animal intestinal health and growth performance. Although some evidence points to the DNA mutagenic potential of sanguinarine (SAN), a major component of MCE, there is a lack of sufficient basic toxicological information on the oral route, posing a potential safety risk for human consumption of food of animal origin. In this study, we assessed the acute oral toxicity, repeated 90-day oral toxicity and 180-day chronic toxicity of MCE in rats and mice and re-evaluated the genotoxicity of MCE using a standard combined in vivo and ex vivo assay. In the oral acute toxicity test, the LD50 for MCE in rats and mice was 1,564.55 mg/kg (95% confidence interval 1,386.97-1,764.95 mg/kg) and 1,024.33 mg/kg (95% confidence interval 964.27-1,087.30 mg/kg), respectively. The dose range tested had no significant effect on hematology, clinical chemistry, and histopathological findings in rodents in the long-term toxicity assessment. The results of the bacterial reverse mutation, sperm abnormality and micronucleus test showed negative results and lack of mutagenicity and teratogenicity; the results of the rat teratogenicity test showed no significant reproductive or embryotoxicity. The results indicate that MCE was safe in the dose range tested in this preclinical safety assessment. This study provides data to support the further development of maximum residue limits (MRLs) for MCE.

Exploring the Anti-inflammatory Effects of Protopine Total Alkaloids of Macleaya Cordata (Willd.) R. Br.

Macleaya cordata (Willd). R. Br. is a Chinese medicinal plant commonly used externally to treat inflammatory-related diseases such as arthritis, sores, and carbuncles. This study aimed to evaluate the anti-inflammatory activity of protopine total alkaloids (MPTAs) in Macleaya cordata (Willd.) R. Br. in vivo tests in rats with acute inflammation showed that MPTA (2.54 and 5.08 mg/kg) showed significant anti-inflammatory activity 6 h after carrageenan injection. Similarly, MPTA (3.67 and 7.33 mg/kg) showed significant anti-inflammatory activity in the mouse ear swelling test. In addition, the potential mechanisms of the anti-inflammatory effects of MPTA were explored based on network pharmacology and molecular docking. The two main active components of MPTA, protopine and allocryptopine, were identified, and the potential targets and signaling pathways of MPTA's anti-inflammatory effects were initially revealed using tools and databases (such as SwissTargetPrediction, GeneCards, and STRING) combined with molecular docking results. This study provides the basis for the application of MPTA as an anti-inflammatory agent.

Ablation of GSDMD Attenuates Neurological Deficits and Neuropathological Alterations After Traumatic Brain Injury.

Pyroptosis plays a significant role in neuroinflammation after traumatic brain injury (TBI). However, the role of pyroptosis executor Gasdermin D (GSDMD) in neurological deficits and neuropathological alterations after TBI have not been elucidated. Our results demonstrated that GSDMD-KO exerted striking neuroprotective effects on motor dysfunction and neuropathological alterations (loss of synaptic proteins, microglia activation, astrogliosis, dendrite injury, and neuron death) at 3 days after TBI. GSDMD-KO inhibited the expression and release of pro-inflammatory cytokine releases (IL-1ß and TNF-α) while promoting those of anti-inflammatory cytokines (IL-10 and TGF-ß1). The temporal pattern of diverse inflammasome signals showed long-lasting elevations of NLRP3, caspase 1, and caspase 1 p20 after TBI, rather than NLRP1, NLRC4 or AIM2, similar to the change in GSDMD postinjury; and NLRP3-KO not only inhibited the expression and cleavage of GSDMD but also attenuated the loss of synaptic proteins and neurological deficits. Notably, RNA sequencing showed both GSDMD-KO and NLRP3-KO reversed the global expression of neuroinflammation- and neuropathology-related genes after TBI. Our findings proved that the inhibition of GSDMD exerts neuroprotective effects after TBI and is mainly driven by the NLRP3 inflammasome. GSDMD serves as a potent therapeutic target for the treatment of TBI.

Safety assessment of MPTA: An oral acute and 90-day sub-chronic toxicity study in Sprague-Dawley rats.

MPTA is a novel extract product derived from Macleaya cordata (Willd.) R. Br., which has good anti-inflammatory and antioxidant activity. The aim of this study was to investigate the acute oral toxicity and 90-day sub-chronic oral toxicity of MPTA. In the acute toxicity study, 50 SD rats of both sexes were randomly divided into 5 groups and dosed in a gradient from 197.53 mg/kg to 1000.00 mg/kg bw. Toxic effects were observed up to 14 days and LD50 was calculated. In a subchronic toxicity test, male and female SD rats were orally dosed repeatedly with 96.40, 19.28, 3.86 mg/kg bw of MPTA for 90 days. In addition, a control group was set up in the subchronic study. The acute toxicity test showed that the oral LD50 of MPTA was 481.99 mg/kg with a 95% confidence interval of 404.24-574.70 mg/kg. MPTA did not appear to induce toxic effects in the longer term in terms of food and water consumption, weight gain, haematological and clinical biochemical parameters and pathological examination. The first data on the potential toxicity of MPTA was provided to highlight the safety of short-term to longer-term oral administration of MPTA, and the experimental results yield and establish a NOEAL of 96.40 mg/kg/d for MPTA.

High glutamate concentration reverses the inhibitory effect of microglial adenosine 2A receptor on NLRP3 inflammasome assembly and activation.

NLRP3 inflammasome plays a crucial role in the innate immune system. Our group previously reported that the microglial adenosine 2A receptor (A2AR) regulates canonical neuroinflammation, which is affected by the glutamate concentration. However, the regulatory effect of A2AR on NLRP3 inflammasome and the effects of glutamate concentration remain unknown. Therefore, we aimed to investigate the regulatory effect of microglial A2AR on NLRP3 inflammasome assembly and activation as well as the effects of glutamate concentration on the inflammasome assembly and activation. Experiments were conducted on magnetically sorted primary microglia from P14 mice. The results showed that pharmacological A2AR activation ameliorated NLRP3 activation under no or low glutamate concentrations, but this effect was reversed by high glutamate concentrations. Moreover, the mRNA levels of NLRP3 inflammasome-related genes were not affected by A2AR activation or the glutamate concentration. We further demonstrated that A2AR activation inhibited the interaction between NLRP3 and caspase 1 under no or low glutamate concentrations while promoting their interaction under high glutamate concentrations. The oligomerization of ASC also showed a similar trend. In conclusion, our findings proved that the high glutamate concentration could reverse the inhibition of A2AR on NLRP3 inflammasome activation by modulating its assembly, which provides new insights into the regulatory effect of A2AR on neuroinflammation under different pathological conditions.

Nitazoxanide, an Antiprotozoal Drug, Reduces Bone Loss in Ovariectomized Mice by Inhibition of RANKL-Induced Osteoclastogenesis.

Nitazoxanide (NTZ) is an FDA-approved anti-parasitic drug with broad-spectrum anti-infective, anti-inflammatory, and antineoplastic potential. However, its regulatory effects on osteoclastogenesis and the underlying mechanisms remain unclear. The present study found that NTZ potently inhibited osteoclast formation at the early stage of receptor activator of NF-κB ligand-induced osteoclastogenesis in a concentration-dependent manner at a non-growth inhibitory concentration. NTZ suppressed actin ring formation and decreased osteoclast marker gene expression, including TRAP, MMP9, and cathepsin K. NTZ significantly impaired the bone resorption activity of osteoclasts. In vivo, ovariectomized mice were treated with 50, 100 and 200 mg/kg/d NTZ for 3 months. NTZ (100 mg/kg/d) administration markedly reduced ovariectomy-induced bone loss by suppressing osteoclast activity. Mechanistically, osteoclastogenesis blockade elicited by NTZ resulted from inhibition of STAT3 phosphorylation, and reduction of the Ca2+ fluorescence intensity and NFATc1 expression. NTZ weakened the binding between STAT3 and the NFATc1 promoter region. Furthermore, enforced NFATc1 expression partly rescued the impaired osteoclast differentiation in NTZ-treated RAW264.7 cells. In summary, NTZ could inhibit osteoclastogenesis and bone loss through modulation of the receptor activator of NF-κB ligand-induced STAT3-NFATc1 signaling pathway, which might be a potential alternative treatment regimen against bone destruction-related diseases including osteoporosis.

Molecular characterization and chemotaxis assay of a CC motif chemokine ligand 25 from Japanese sea bass (Lateolabrax japonicus).

CC motif chemokine ligand 25 (CCL25) is a key chemokine that attracts various types of leukocytes, such as activated peritoneal macrophages. However, information on CCL25 in fish is limited. Here, a CCL25 gene (LjCCL25) was identified from Japanese sea bass (Lateolabrax japonicus), showing upregulation in multiple tissues against Vibrio harveyi infection. The recombinant LjCCL25 (rLjCCL25) only significantly induced the migration of monocytes/macrophages (MO/MΦ) both in vitro and in vivo, but didn't induce that of neutrophils or lymphocytes. Additionally, rLjCCL25 only induced migration of the lipopolysaccharide-stimulated MO/MΦ (M1 type). Knockdown of Japanese sea bass CC chemokine receptor 9 (LjCCR9) expression in MO/MФ by RNA interference inhibited the LjCCL25-induced chemotaxis of resting and M1 type MO/MФ. Moreover, administration of 300 ng/g rLjCCL25 effectively increased the survival of V. harveyi-infected fish and decreased bacterial load. Our study demonstrates that LjCCL25 functions as an MO/MФ chemoattractant via LjCCR9 in Japanese sea bass against V. harveyi.

Iguratimod inhibits osteoclastogenesis by modulating the RANKL and TNF-α signaling pathways.

BACKGROUND: Iguratimod, a small molecular drug, has been proven to have effective bone protection for treatment of patients with bone loss-related diseases, such as rheumatoid arthritis (RA). However, the exact bone protective mechanism of iguratimod remains to be determined. The purpose of this study was to better explore the underlying mechanism of bone protection of iguratimod. METHODS: Bone marrow monocytes from C57/BL6 mice were stimulated with either RANKL or TNF-α plus M-CSF. The effects of iguratimod on morphology and function of osteoclasts were confirmed by TRAP staining and bone resorption assay, respectively. The expression of osteoclast related genes was detected by RT-PCR and the activation of signal pathway was detected by Western blotting. We used rodent models of osteoporosis (ovariectomy) and of arthritis (modified TNF-α-induced osteoclastogenesis) to evaluate the osteoprotective effect of iguratimod in vivo. RESULTS: Iguratimod potently inhibited osteoclast formation in a dose-dependent manner at the early stage of RANKL-induced osteoclastogenesis, whereas iguratimod had no effect on M-CSF-induced proliferation and RANK expression in bone marrow monocytes. Bone resorption was significantly reduced by both early and late addition of iguratimod. Administration of iguratimod prevented bone loss in ovariectomized mice. The blockage of osteoclastogenesis elicited by iguratimod results from abrogation of the p38、ERK and NF-κB pathways induced by RANKL. Importantly, Iguratimod also dampened TNF-α-induced osteoclastogenesis in vitro and attenuated osteoclasts generation in vivo through disrupting NF-κB late nuclear translocation without interfering with IκBα degradation. CONCLUSIONS: Iguratimod not only suppresses osteoclastogenesis by interfering with RANKL and TNF-α signals, but also inhibits the bone resorption of mature osteoclasts. These results provided promising evidence for the therapeutic application of iguratimod as a unique treatment option against RA and especially in prevention of bone loss.

MOSPD2 is a receptor mediating the LEAP-2 effect on monocytes/macrophages in a teleost, Boleophthalmus pectinirostris.

Liver-expressed antimicrobial peptide 2 (LEAP-2) is a cationic peptide that plays an important role in a host's innate immune system. We previously demonstrated that mudskipper ( Boleophthalmus pectinirostris) LEAP-2 (BpLEAP-2) induces chemotaxis and activation of monocytes/ macrophages (MO/MФ). However, the molecular mechanism by which BpLEAP-2 regulates MO/MΦ remains unclear. In this study, we used yeast two-hybrid cDNA library screening to identify mudskipper protein(s) that interacted with BpLEAP-2, and characterized a sequence encoding motile sperm domain-containing protein 2 (BpMOSPD2). The interaction between BpLEAP-2 and BpMOSPD2 was subsequently confirmed by co-immunoprecipitation (Co-IP). Sequence analyses revealed that the predicted BpMOSPD2 contained an N-terminal extracellular portion composed of a CRAL-TRIO domain and a motile sperm domain, a C-terminal transmembrane domain, and a short cytoplasmic tail. Phylogenetic tree analysis indicated that BpMOSPD2 grouped tightly with fish MOSPD2 homologs and was most closely related to that of the Nile tilapia ( Oreochromis niloticus). The recombinant BpMOSPD2 was produced by prokaryotic expression and the corresponding antibody was prepared for protein concentration determination. RNA interference was used to knockdown BpMOSPD2 expression in the mudskipper MO/MФ, and the knockdown efficiency was confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Knockdown of BpMOSPD2 significantly inhibited BpLEAP-2-induced chemotaxis of mudskipper MO/MФ and BpLEAP-2-induced bacterial killing activity. Furthermore, knockdown of BpMOSPD2 inhibited the effect of BpLEAP-2 on mRNA expression levels of BpIL-10, BpTNFα, BpIL-1ß, and BpTGFß in MO/MФ. In general, BpMOSPD2 directly interacted with BpLEAP-2, and mediated the effects of BpLEAP-2 on chemotaxis and activation of mudskipper MO/MФ. This is the first identification of MOSPD2 as a receptor for LEAP-2.