INT-777 attenuates NLRP3-ASC inflammasome-mediated neuroinflammation via TGR5/cAMP/PKA signaling pathway after subarachnoid hemorrhage in rats

BACKGROUND

Inflammasome-mediated neuroinflammation plays an important role in the pathogenesis of early brain injury (EBI) following subarachnoid hemorrhage (SAH). The activation of the TGR5 receptor has been shown to be neuroprotective in a variety of neurological diseases. This study aimed to investigate the effects of the specific synthetic TGR5 agonist, INT-777, in attenuating NLRP3-ASC inflammasome activation and reducing neuroinflammation after SAH.

METHODS

One hundred and eighty-four male Sprague Dawley rats were used. SAH was induced by the endovascular perforation. INT-777 was administered intranasally at 1 h after SAH induction. To elucidate the signaling pathway involved in the effect of INT-777 on inflammasome activation during EBI, TGR5 knockout CRISPR and PKA inhibitor H89 were administered intracerebroventricularly and intraperitoneally at 48 h and 1 h before SAH. The SAH grade, short- and long-term neurobehavioral assessments, brain water content, western blot, immunofluorescence staining, and Nissl staining were performed.

RESULTS

The expressions of endogenous TGR5, p-PKA, and NLRP3-ASC inflammasome were increased after SAH. INT-777 administration significantly decreased NLRP3-ASC inflammasome activation in microglia, reduced brain edema and neuroinflammation, leading to improved short-term neurobehavioral functions at 24 h after SAH. The administration of TGR5 CRISPR or PKA inhibitor (H89) abolished the anti-inflammation effects of INT-777, on NLRP3-ASC inflammasome, pro-inflammatory cytokines (IL-6, IL-1β, and TNF-a), and neutrophil infiltration at 24 h after SAH. Moreover, early administration of INT-777 attenuated neuronal degeneration in hippocampus on 28 d after SAH.

CONCLUSIONS

INT-777 attenuated NLRP3-ASC inflammasome-dependent neuroinflammation in the EBI after SAH, partially via TGR5/cAMP/PKA signaling pathway. Early administration of INT-777 may serve as a potential therapeutic strategy for EBI management in the setting of SAH.

Inhibition of lysophosphatidic acid receptor 1 attenuates neuroinflammation via PGE2/EP2/NOX2 signalling and improves the outcome of intracerebral haemorrhage in mice

Lysophosphatidic acid receptor 1 (LPA1) plays a critical role in proinflammatory processes in the central nervous system by modulating microglia activation. The aim of this study was to explore the anti-inflammatory effects and neurological function improvement of LPA1 inhibition after intracerebral haemorrhage (ICH) in mice and to determine whether prostaglandin E2 (PGE2), E-type prostaglandin receptor 2 (EP2), and NADPH oxidase 2 (NOX2) signalling are involved in LPA1-mediated neuroinflammation. ICH was induced in CD1 mice by autologous whole blood injection. AM966, a selective LPA1 antagonist, was administered by oral gavage 1 h and 12 h after ICH. The LPA1 endogenous ligand, LPA was administered to verify the effect of LPA1 activation. To elucidate potential inflammatory mechanisms of LPA1, the selective EP2 activator butaprost was administered by intracerebroventricular injection with either AM966 or LPA1 CRISPR knockout (KO). Water content of the brain, neurobehavior, immunofluorescence staining, and western blot were performed. After ICH, EP2 was expressed in microglia whereas LPA1 was expressed in microglia, neurons, and astrocytes, which peaked after 24 h. AM966 inhibition of LPA1 improved neurologic function, reduced brain oedema, and suppressed perihematomal inflammatory cells after ICH. LPA administration aggravated neurological deficits after ICH. AM966 treatment and LPA1 CRISPR KO both decreased the expressions of PGE2, EP2, NOX2, NF-κB, TNF-α, IL-6, and IL-1β expressions after ICH, which was reversed by butaprost. This study demonstrated that inhibition of LPA1 attenuated neuroinflammation caused by ICH via PGE2/EP2/NOX2 signalling pathway in mice, which consequently improved neurobehavioral functions and alleviated brain oedema. LPA1 may be a promising therapeutic target to attenuate ICH-induced secondary brain injury.

Melanocortin 1 receptor attenuates early brain injury following subarachnoid hemorrhage by controlling mitochondrial metabolism via AMPK/SIRT1/PGC-1α pathway in rats

Mitochondria-mediated oxidative stress and apoptosis contribute greatly to early brain injury (EBI) following subarachnoid hemorrhage (SAH). This study hypothesized that activation of melanocortin 1 receptor (MC1R), using BMS-470539, attenuates EBI by controlling mitochondrial metabolism after SAH. Methods: We utilized BMS-470539, MSG-606, selisistat, and PGC-1α to verify the neuroprotective effects of MC1R. We evaluated short- and long-term neurobehavior after SAH. Western blotting, immunofluorescence, and Golgi staining techniques were performed to assess changes in protein levels. Results: The results of western blotting suggested that the expression of SIRT1 and PGC-1α were increased, reaching their peaks at 24 h following SAH. Moreover, BMS-470539 treatment notably attenuated neurological deficits, and also reduced long-term spatial learning and memory impairments caused by SAH. The underlying neuroprotective mechanisms of the BMS-470539/MC1R system were mediated through the suppression of oxidative stress, apoptosis, and mitochondrial fission by increasing the levels of SIRT1, PGC-1α, UCP2, SOD, GPx, Bcl-2, cyto-Drp1, and ATP, while decreasing the levels of cleaved caspase-3, Bax, mito-Drp1, ROS, GSH/GSSG, and NADPH/NADP+ ratios. The neuroprotective effects of the BMS-470539/MC1R system were significantly abolished by MSG-606, selisistat, and PGC-1α siRNA. Conclusions: The activation of MC1R with BMS-470539 significantly attenuated EBI after SAH by suppressing the oxidative stress, apoptosis, and mitochondrial fission through the AMPK/SIRT1/PGC-1α signaling pathway.

The Stroke-Induced Blood-Brain Barrier Disruption: Current Progress of Inspection Technique, Mechanism, and Therapeutic Target

Stroke is one of the leading causes of mortality and morbidity worldwide. The blood-brain barrier (BBB) is a characteristic structure of microvessel within the brain. Under normal physiological conditions, the BBB plays a role in the prevention of harmful substances entering into the brain parenchyma within the central nervous system. However, stroke stimuli induce the breakdown of BBB leading to the influx of cytotoxic substances, vasogenic brain edema, and hemorrhagic transformation. Therefore, BBB disruption is a major complication, which needs to be addressed in order to improve clinical outcomes in stroke. In this review, we first discuss the structure and function of the BBB. Next, we discuss the progress of the techniques utilized to study BBB breakdown in in-vitro and in-vivo studies, along with biomarkers and imaging techniques in clinical settings. Lastly, we highlight the mechanisms of stroke-induced neuroinflammation and apoptotic process of endothelial cells causing BBB breakdown, and the potential therapeutic targets to protect BBB integrity after stroke. Secondary products arising from stroke-induced tissue damage provide transformation of myeloid cells such as microglia and macrophages to pro-inflammatory phenotype followed by further BBB disruption via neuroinflammation and apoptosis of endothelial cells. In contrast, these myeloid cells are also polarized to anti-inflammatory phenotype, repairing compromised BBB. Therefore, therapeutic strategies to induce anti-inflammatory phenotypes of the myeloid cells may protect BBB in order to improve clinical outcomes of stroke patients.

The Dual Role of Microglia in Blood-Brain Barrier Dysfunction after Stroke

It is well-known that stroke is one of the leading causes of death and disability all over the world. After a stroke, the blood-brain barrier subsequently breaks down. The BBB consists of endothelial cells surrounded by astrocytes. Microglia, considered the long-living resident immune cells of the brain, play a vital role in BBB function. M1 microglia worsen BBB disruption, while M2 microglia assist in repairing BBB damage. Microglia can also directly interact with endothelial cells and affect BBB permeability. In this review, we are going to discuss the mechanisms responsible for the dual role of microglia in BBB dysfunction after stroke.

Pituitary Adenylate Cyclase-Activating Polypeptide: A Promising Neuroprotective Peptide in Stroke

The search for viable, effective treatments for acute stroke continues to be a global priority due to the high mortality and morbidity. Current therapeutic treatments have limited effects, making the search for new treatments imperative. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a well-established cytoprotective neuropeptide that participates in diverse neural physiological and pathological activities, such as neuronal proliferation, differentiation, and migration, as well as neuroprotection. It is considered a promising treatment in numerous neurological diseases. Thus, PACAP bears potential as a new therapeutic strategy for stroke treatment. Herein, we provide an overview pertaining to the current knowledge of PACAP, its receptors, and its potential neuroprotective role in the setting of stroke, as well as various mechanisms of neuroprotection involving ionic homeostasis, excitotoxicity, cell edema, oxidative stress, inflammation, and cell death, as well as the route of PACAP administration.

Delayed Recanalization-How Late Is Not Too Late?

Stroke has become the second most prevalent cause of mortality in the world. Currently, the treatment of ischemic stroke is based on thrombolytic and thrombectomy therapy shortly after the ischemic event (≤ 4.5 h for thrombolytic strategies; ≤ 6 h for thrombectomy strategies). However, the majority of patients are unable to receive prompt treatment, particularly in undeveloped countries. Alternative solutions are lacking for those patients that miss the optimal window of opportunity for treatment. Recently, new developments in imaging techniques and intravascular interventional devices enable the expansion of the window of opportunity for treating stroke patients. Clinical studies have reported that delayed recanalization at 24 h, or even more than 1 month, was beneficial for some patients. However, the mechanisms of neuroprotection that underly the delayed recanalization in these ischemic stroke patients remain unclear. In this review, we will summarize the clinical studies of delayed recanalization, and organize them according to the duration of occlusion. Additionally, we will discuss the changing guidelines and possible mechanisms based on animal research, and attempt to draw conclusions and future perspectives.

[Study on the best entry region and trajectory of anterior transpedicular root screws]

Objective: To evaluate the best entry region and trajectory of anterior transpedicular root screws (ATPRS). Methods: From January 2018 to May 2019, 50 cervical CT date integral of healthy people were selected from Ningbo No. 6 Hospital and were confirmed no obvious defect. Of these, 24 cases were males and 26 were females, aged 20-49 (32±5) years. The CT data was imported into Mimics by DICOM format, then 3D reconstruction was performed. In the coronal plane, the area from the centreline of the anterior of C(3-7) to the left Z-line(marked a line through the intersection of the anterior of the luschak joint and upper endplates, parallel to the centralline of the anterior of the vertebral body) was divided into nine areas. Then virtual screw with diameter of 3.5 mm was inserted. Record the length of screw of each area (L), the angle between screw and the posterior of the vertebral body in horizontal plane(α), the angle between screw and the anterior of the vertebral body in sagittal plane (β), individually. The data between groups were compared by independent sample t test. Results: The best regions were zone 9 of C(3), C(4); zone 8, 9 of C(5); zone 2-3, 5-9 of C(6); zone 1-9 of C(7) in men. And these were zone 9 of C(3); zone 3, 6, 8 and 9 of C(4), C(5); zone 2-3, 5-9 of C(6); zone 1-9 of C(7) in women. The distribution of best region was almost the same in men and women, zone 9 of each segment was the best region, and the screw length was the longest. It increased gradually from C(3) to C(7). C(3) had the least region, C(4) and C(5) had less, while C(6) and C(7) had the most. The horizontal angle of C(3-7) in men and women were 44.0°-47.2°, 40.2°-45.3° in zone 1, 4 and 7, respectively; 35.1°-41.4°, 34.6°-38.7° in zone 2, 5 and 8, respectively; 30.0°-37.2°, 30.2°-34.5° in zone 3, 6 and 9, respectively; and it demonstrated a gradually decreased trend. The sagittal angle of C(3-7) in men and women was 85.3°-97.4°, 80.5°-88.9° in zone 1-3, respectively; 101.2°-113.7°, 101.0°-109.3° in zone 4-6, respectively; 116.6°-128.8°, 119.9°-125.3° in zone 7-9, respectively; and it demonstrated a gradually increased trend. There was no significant difference in the horizontal and sagittal angle between men and women (both P>0.05). Conclusions: Anterior transpedicular root screw is a feasible internal fixation technique. It has wide region and the Z-line can be used as a reference for screw placement.

[Investigation of detection capacities of laboratories in sexually transmitted disease surveillance areas in China]

Objective: To understand the detection capacities of the laboratories in medical institutions in national sexually transmitted disease (STD) surveillance areas in China. Methods: A cross-sectional study was conducted to investigate the applications of STD tests in laboratories of the medical institutions in 105 STD surveillance areas in China, the proportion of each STD test application was calculated and the differences among medical institutions were compared. Results: In 752 medical institutions, the proportions of Treponema pallidum serological test and non-Treponema pallidum serological test applications were 97.5% (733/752) and 91.4% (687/752), respectively. The proportions of gonococcal culture and Chlamydia trachomatis nucleic acid test applications were 48.4% (364/752) and 23.4% (176/752), respectively. The application proportions of all tests for herpes simplex virus type 2 (HSV-2) and human papillomavirus (HPV) were less than 40%. In medical institutions at provincial, prefectural and county levels, the application proportions of serological tests of Treponema and non-Treponema were all more than 90%, and the application proportions of gonococcal culture were 66.9% (83/124), 46.9% (197/420) and 47.4% (82/173) respectively, the application proportions of Chlamydia trachomatis nucleic acid test were 29.0% (36/124), 25.0% (105/420) and 19.7% (34/173) respectively. The application proportions of syphilis and gonorrhea tests and chlamydia nucleic acid test in public medical institutions were higher than those in private/joint venture medical institutions and higher in dermatological specialized hospitals than those in general hospitals and maternal and child health centers. The application proportions of STD tests in medical institutions in eastern China and central southern China were generally higher than those in other areas, and the lowest was found in northwestern China. Conclusions: Serological tests for syphilis have been carried out widely in medical institutions in all STD surveillance areas in China, but there were insufficient use of tests for gonococcal culture and Chlamydia trachomatis nucleic acid. The application proportions of STD tests vary in medical institutions at different levels and with different types and ownerships, and the development of STD testing is unbalanced in different areas. It is necessary to strengthen the capacity building of gonococcal culture and Chlamydia trachomatis nucleic acid test, and strengthen the capacity building of STD testing in grassroots, private/joint venture medical institutions and those in underdeveloped western areas.

Inhibition of EZH2 (Enhancer of Zeste Homolog 2) Attenuates Neuroinflammation via H3k27me3/SOCS3/TRAF6/NF-κB (Trimethylation of Histone 3 Lysine 27/Suppressor of Cytokine Signaling 3/Tumor Necrosis Factor Receptor Family 6/Nuclear Factor-κB) in a Rat Model of Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Neuroinflammation has been proven to play an important role in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). EZH2 (enhancer of zeste homolog 2)-mediated H3K27Me3 (trimethylation of histone 3 lysine 27) has been recognized to play a critical role in multiple inflammatory diseases. However, there is still a lack of evidence to address the effect of EZH2 on the immune response of SAH. Therefore, the aim of this study was to determine the role of EZH2 in SAH-induced neuroinflammation and explore the effect of EZH2 inhibition with its specific inhibitor EPZ6438.

METHODS

The endovascular perforation method was performed on rats to induce subarachnoid hemorrhage. EPZ6438, a specific EZH2 inhibitor, was administered intraperitoneally at 1 hour after SAH. SOCS3 (Suppressor of cytokine signaling 3) siRNA and H3K27me3 CRISPR were administered intracerebroventricularly at 48 hours before SAH to explore potential mechanisms. The SAH grade, short-term and long-term neurobehavioral tests, immunofluorescence staining, and western blots were performed after SAH.

RESULTS

The expression of EZH2 and H3K27me3 peaked at 24 hours after SAH. In addition, inhibition of EZH2 with EPZ6438 significantly improved neurological deficits both in short-term and long-term outcome studies. Moreover, EPZ6438 treatment significantly decreased the levels of EZH2, H3K27Me3, pathway-related proteins TRAF6 (TNF [tumor necrosis factor] receptor family 6), NF-κB (nuclear factor-κB) p65, proinflammatory cytokines TNF-α, IL (interleukin)-6, IL-1β, but increased the expression levels of SOCS3 and anti-inflammatory cytokine IL-10. Furthermore, administration of SOCS3 siRNA and H3k27me3-activating CRISPR partly abolished the neuroprotective effect of EPZ6438, which indicated that the neuroprotective effect of EPZ6438 acted, at least partly, through activation of SOCS3.

CONCLUSIONS

In summary, the inhibition of EZH2 by EPZ6438 attenuated neuroinflammation via H3K27me3/SOCS3/TRAF6/NF-κB signaling pathway after SAH in rats. By targeting EZH2, this study may provide an innovative method to ameliorate early brain injury after SAH.

GW0742 activates miR-17-5p and inhibits TXNIP/NLRP3-mediated inflammation after hypoxic-ischaemic injury in rats and in PC12 cells

This study aimed to investigate the effects of PPAR‐β/δ receptor agonist GW0742 on neuroinflammation in a rat model of hypoxia‐ischaemia (HI) and in PC12 cells in OGD model. HI was induced by ligating the common carotid artery and inducing hypoxia for 150 minutes. Immunofluorescence was used for quantification of microglia activation and for determining cellular localization of PPAR‐β/δ. Expression of proteins was measured by Western blot. Activation of miR‐17‐5p by GW0742 was assessed in PC12 cells by Dual‐Luciferase Reporter Gene Assay. The endogenous expression of TXNIP, NLRP3, cleaved caspase‐1 and IL‐1β was increased after HI. GW0742 treatment significantly reduced the number of activated pro‐inflammatory microglia in ipsilateral hemisphere after HI. Mechanistically, GW0742 significantly decreased the expression of TXNIP, NLRP3, IL‐6 and TNF‐α. Either PPAR‐β/δ antagonist GSK3787, miR‐17‐5p inhibitor, or TXNIP CRISPR activation abolished the anti‐inflammatory effects of GW0742. Activation of PPAR‐β/δ by GW0742 activated miR‐17‐5p expression in PC12 cells and increased cell viability after OGD, which was accompanied by decreased expression of TXNIP and reduced secretion of IL‐1β and TNF‐α. In conclusion, GW0742 may be a promising neurotherapeutic for the management of HI patients.

Recombinant CCL17 Enhances Hematoma Resolution and Activation of CCR4/ERK/Nrf2/CD163 Signaling Pathway After Intracerebral Hemorrhage in Mice

Hematoma is a crucial factor leading to poor prognosis after intracerebral hemorrhage (ICH). Promoting microglial phagocytosis to enhance hematoma resolution may be an important therapeutic target for recovery after ICH. C-C chemokine receptor 4 (CCR4) is important for regulating immune balance in the central nervous system. However, whether CCR4 activation can attenuate hematoma after ICH remains unknown. We aimed to evaluate whether CCL17 (a specific ligand of CCR4) treatment can promote hematoma resolution through CCR4/ERK/Nrf2/CD163 pathway after ICH. A total of 261 adult male CD1 mice were used. Mice were subjected to intrastriatal injection of autologous blood to induce ICH and randomly assigned to receive recombinant CCL17 (rCCL17) or vehicle which was administered intranasally at 1 h after ICH. To elucidate the underlying mechanism, C021, a selective inhibitor of CCR4 and ML385 and a selective inhibitor of Nrf2 were administered 1 h prior to ICH induction. Clustered regularly interspaced short palindromic repeats (CRISPR) knockout for CD163 was administered by intracerebroventricular injection at 48 h before ICH. Brain edema, short- and long-term neurobehavior evaluation, hematoma volume, hemoglobin content, western blot, and immunofluorescence staining were performed. Endogenous CCL17, CCR4, and CD163 expression increased and peaked at 72 h after ICH. CCR4 was expressed by microglia. CCR4 activation with rCCL17 significantly improved neurobehavioral scores and reduced hematoma volume and brain edema compared with vehicle. Moreover, rCCL17 treatment significantly promoted phosphorylation of ERK1/2, increased the expression Nrf2, and upregulated CD163 expression after ICH. The protective effects of rCCL17 were abolished by administration of C021, ML385, and CD163 CRISPR knockout. This study demonstrated that CCR4 activation with rCCL17 promoted hematoma resolution by increasing CD163 expression and CCR4/ERK/Nrf2 pathway activation after ICH, thereby reducing brain edema and improving neurological function. Overall, our study suggests that CCR4 activation may be a potential therapeutic strategy to attenuate hematoma in early brain injury after ICH.

Pituitary Adenylate Cyclase-Activating Polypeptide Attenuates Brain Edema by Protecting Blood-Brain Barrier and Glymphatic System After Subarachnoid Hemorrhage in Rats

Brain edema is a vital contributor to early brain injury after subarachnoid hemorrhage (SAH), which is responsible for prolonged hospitalization and poor outcomes. Pharmacological therapeutic targets on edema formation have been the focus of research for decades. Pituitary adenylate cyclase-activating polypeptide (PACAP) has been shown to participate in neural development and brain injury. Here, we used PACAP knockout CRISPR to demonstrate that endogenous PACAP plays an endogenous neuroprotective role against brain edema formation after SAH in rats. The exogenous PACAP treatment provided both short- and long-term neurological benefits by preserving the function of the blood-brain barrier and glymphatic system after SAH. Pretreatment of inhibitors of PACAP receptors showed that the PACAP-involved anti-edema effect and neuroprotection after SAH was facilitated by the selective PACAP receptor (PAC1). Further administration of adenylyl cyclase (AC) inhibitor and sulfonylurea receptor 1 (SUR1) CRISPR activator suggested that the AC-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) axis participated in PACAP signaling after SAH, which inhibited the expression of edema-related proteins, SUR1 and aquaporin-4 (AQP4), through SUR1 phosphorylation. Thus, PACAP may serve as a potential clinical treatment to alleviate brain edema in patients with SAH.

Dietary L-arginine supplementation enhances growth performance, intestinal antioxidative capacity, immunity and modulates gut microbiota in yellow-feathered chickens

This study investigated the effects of dietary Arginine (Arg) on performance, intestinal antioxidative capacity, immunity, and gut microbiota in Chinese yellow-feathered chickens. One thousand two hundred 1-day-old female Qingyuan partridge chickens were randomly assigned to 5 groups with 6 replicates of 40 birds each. Chickens were fed diets with 5 levels of total Arg (8.5, 9.7, 10.9, 12.1, and 13.3 g/kg) without antibiotics for 30 d. The ADFI, ADG, and feed conversion ratio were improved with dietary Arg levels (P < 0.05). The proportions of CD3⁺ and CD4⁺/CD8⁺ lymphocytes responded in a linear (P < 0.05) manner and those of CD4⁺ in a linear or quadratic (P < 0.05) manner as dietary Arg levels increased. Dietary Arg level had a linear (P < 0.05) or quadratic (P < 0.05) effect on the gene expression of glutathione peroxidase 1, heme oxygenase 1, nuclear factor erythroid 2-related factor 2, and the activities of glutathione peroxidase and total antioxidative capacity in the jejunum and ileum. The relative expression of IL-1β, myeloid differentiation primary response 88, and Toll-like receptor 4 decreased linearly (P < 0.05) in the ileum with increasing dietary Arg levels; secretory IgA contents were increased. In addition, sequencing data of 16S rRNA indicated that dietary Arg increased the relative abundance of Firmicutes phylum, Romboutsia and Candidatus Arthromitus genera, while decreased that of Clostridium sensu stricto 1. A diet containing 12.1 g Arg/kg promoted growth performance, intestinal antioxidation, and innate immunity and modulated gut microbiota in yellow-feathered chickens.

[A nomogram to predict non-sentinel lymph node metastasis for breast cancer patients with positive axillary sentinel lymph node]

Objective: To identify the risk factors of non-sentinel lymph node (nSLN) metastasis in breast cancer patients with 1~2 positive axillary sentinel lymph node (SLN) and construct an accurate prediction model. Methods: Retrospective chart review was performed in 917 breast cancer patients who underwent surgery treatment between 2002 and 2017 and pathologically confirmed 1-2 positive SLNs. According to the date of surgery, patients were divided into training group (497 cases) and validation group (420 cases). A nomogram was built to predict nSLN metastasis and the accuracy of the model was validated. Results: Among the 917 patients, 251 (27.4%) had nSLN metastasis. Univariate analysis showed tumor grade, lymphovascular invasion (LVI), extra-capsular extension (ECE), the number of positive and negative SLN and macro-metastasis of SLN were associated with nSLN metastasis (all P<0.05). Multivariate Logistic regression analysis showed the numbers of positive SLN, negative SLN and macro-metastasis of SLN were independent predictors of nSLN metastasis (all P<0.05). A nomogram was constructed based on the 6 factors. The area under the receiver operating characteristic curve was 0.718 for the training group and 0.742 for the validation group. Conclusion: We have developed a nomogram that uses 6 risk factors commonly available to accurately estimate the likelihood of nSLN metastasis for individual patient, which might be helpful for radiation oncologists to make a decision on regional nodal irradiation.

Rh-relaxin-2 attenuates degranulation of mast cells by inhibiting NF-κB through PI3K-AKT/TNFAIP3 pathway in an experimental germinal matrix hemorrhage rat model

BACKGROUND

Mast cells play an important role in early immune reactions in the brain by degranulation and the consequent inflammatory response. Our aim of the study is to investigate the effects of rh-relaxin-2 on mast cells and the underlying mechanisms in a germinal matrix hemorrhage (GMH) rat model.

METHODS

One hundred seventy-three P7 rat pups were subjected to GMH by an intraparenchymal injection of bacterial collagenase. Clodronate liposome was administered through intracerebroventricular (i.c.v.) injections 24 h prior to GMH to inhibit microglia. Rh-relaxin-2 was administered intraperitoneally at 1 h and 13 h after GMH. Small interfering RNA of RXFP1 and PI3K inhibitor LY294002 were given by i.c.v. injection. Post-GMH evaluation included neurobehavioral function, Western blot analysis, immunofluorescence, Nissl staining, and toluidine blue staining.

RESULTS

Our results demonstrated that endogenous relaxin-2 was downregulated and that RXFP1 level peaked on the first day after GMH. Administration of rh-relaxin-2 improved neurological functions, attenuated degranulation of mast cells and neuroinflammation, and ameliorated post-hemorrhagic hydrocephalus (PHH) after GMH. These effects were associated with RXFP1 activation, increased expression of PI3K, phosphorylated AKT and TNFAIP3, and decreased levels of phosphorylated NF-κB, tryptase, chymase, IL-6, and TNF-α. However, knockdown of RXFP1 and PI3K inhibition abolished the protective effects of rh-relaxin-2.

CONCLUSIONS

Our findings showed that rh-relaxin-2 attenuated degranulation of mast cells and neuroinflammation, improved neurological outcomes, and ameliorated hydrocephalus after GMH through RXFP1/PI3K-AKT/TNFAIP3/NF-κB signaling pathway.

FSLLRY-NH2 Improves Neurological Outcome After Cardiac Arrest in Rats

AIM

To evaluate the effect of FSLLRY-NH2, a protease-activated receptor 2 (PAR2) inhibitor, on neurocognitive impairment and hippocampal neuronal degeneration in the setting of asphyxial cardiac arrest (ACA)-induced global cerebral ischemia (GCI) in rats.

MATERIAL AND METHODS

A total of 43 Sprague-Dawley male rats were used. Shams and rats resuscitated from 9 minutes of ACA were randomized to two separate experiments including time course and short-term neurological outcomes. FSLLRY-NH2 (50 microgram [μg] per rat) was administered intranasally at 1 hour postresuscitation. Neurological function and hippocampal neuronal degeneration were evaluated after ACA.

RESULTS

Significant neurological function decline and hippocampal neuron degeneration were observed in ACA animals as compared with the shams. Treatment with FSLLRY-NH2 significantly improved neurological outcome and reduced the number of degenerating hippocampal neurons after ACA.

CONCLUSION

Targeting PAR2 may be a novel therapeutic approach in the management of neurological dysfunction after cardiac arrest-associated ischemic injury.

Role of peroxisome proliferator-activated receptors in stroke prevention and therapy-The best is yet to come?

Role of peroxisome proliferator-activated receptors (PPARs) in the pathophysiology of stroke and protective effects of PPAR ligands have been widely investigated in the last 20 years. Activation of all three PPAR isoforms, but especially PPAR-γ, was documented to limit postischemic injury in the numerous in vivo, as well as in in vitro studies. PPARs have been demonstrated to act on multiple mechanisms and were shown to activate multiple protective pathways related to inflammation, apoptosis, BBB protection, neurogenesis, and oxidative stress. The aim of this review was to summarize two decades of PPAR research in stroke with emphasis on in vivo animal studies. We focus on each PPAR receptor separately and detail their implication in stroke. This review also discusses recent clinical efforts in the field and the epidemiological data with regard to role of PPAR polymorphisms in susceptibility to stroke, and tries to draw conclusions and describe future perspectives.

[Effects of titanium dioxide nanoparticles on fecal metabolome in rats after oral administration for 90 days]

OBJECTIVE

To explore the effects and related mechanisms of oral exposure titanium dioxide nanoparticles (TiO₂ NPs) for 90 days on the intestinal and the gut microbiota of rats, through fecal metabolomics.

METHODS

Twelve 4-week-old clean-grade Sprague Dawley (SD) rats were randomly de-vided into 2 groups by body weight, treated with TiO₂ NPs at dose of 0 or 50 mg/kg body weight everyday respectively for 90 days. The solution of each infection was freshly prepared and shocked fully by ultrasonic. Characterization of the particle size, crystal form, purity, and specific surface area of TiO₂ NPs was conducted. And the fresh feces of the rats were collected on the 90th day. After lyophilized and hydrophilic phase extraction, ultra performance liquid chromatography-Q-exactive orbitrap-high-resolution mass spectrometry system (UPLC-QEMS) was utilized for non-targeted determination of fecal meta-bolites. The metabolites were identified and labeled through Compound Discoverer 3.0 software, and used for subsequent metabolomics analysis. Bioinformatics analysis was carried out including unsupervised principal component analysis and supervised orthogonal projection to latent structure discriminant analysis for the differential metabolites between the two groups. The differential metabolites were followed-up for Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

RESULTS

Compared with the control group, the body weight of the rats was significantly reduced (P<0.05) in the treatment group. A total of 22 metabolites in fecal metabolomics showed significant changes. Among them, xanthine, 1-methyladenine, 3-hydroxypyridine, methionine sulfoxide, pyridoxine, 1,5-isoquinolinediol, N-acetylornithine, N-acetyl-D-galactosamine, L-citrulline, L-methionine, leucine, DL-tryptophan, L-ornithine, 4-methyl-5-thiazoleethanol, and L-glutamic acid totaled 15 metabolites increased significantly. N-acetylhistamine, D-pipecolinic acid, imidazolelactic acid, L-valine, 2,3,4,6-tetramethylpyrazine, caprolactam, and histamine totaled 7 metabolites decreased significantly. N-acetylhistamine, L-valine and methionine sulfoxide were changed more than 16 times. Analysis of KEGG pathway revealed that the two metabolic pathways arginine biosynthesis and aminoacyl-tRNA biosynthesis were significantly changed (false discover rate < 0.05, pathway impact > 0.1).

CONCLUSION

Oral exposure to TiO₂ NPs for 90 days could disrupt the metabolism of the intestine and gut microbiota, causing significant changes in metabolites and metabolic pathways which were related to inflammatory response, oxidative stress, glucose homeostasis, blood system and amino acid homeostasis in rat feces. It is suggested that the toxic effect of TiO₂ NPs on rats may be closely related to intestinal and gut microbiota metabolism.

The potential of Slit2 as a therapeutic target for central nervous system disorders

Introduction: Slit2 is an extracellular matrix protein that regulates migration of developing axons during central nervous system (CNS) development. Roundabout (Robo) receptors expressed by various cell types in the CNS, mediate intracellular signal transduction pathways for Slit2. Recent studies indicate that Slit2 plays important protective roles in a myriad of processes such as cell migration, immune response, vascular permeability, and angiogenesis in CNS pathologies. Areas covered: This review provides an overview of the diverse functions of Slit2 in CNS disorders and discusses the potential of Slit2 as a therapeutic target. We reviewed preclinical studies reporting the role of Slit2 in various CNS disease models, transgenic animal research, and rodent models that utilized Slit2 as a therapy. Expert opinion: Slit2 exerts a wide array of beneficial effects ranging from anti-migration, blood-brain barrier (BBB) protection, inhibition of peripheral immune cell infiltration, and anti-apoptosis in various disease models. However, a dual role of Slit2 in endothelial permeability has been observed in transgenic animals. Further research on Slit2 will be crucial including key issues such as effects of transgenic overexpression versus exogenous Slit2, function of Slit2 dependent on cellular expression of Robo receptors and the underlying pathology for potential clinical translation.

[Subclinical heart injury in patients receiving hypofractionated radiotherapy after breast conserving surgery: a preliminary analysis of prospective study]

Objective: To evaluate the incidence of early cardiac injury in patients with left-sided breast cancer receiving hypofractionated radiotherapy after breast conserving surgery, and to investigate the correlation between cardiac injury and hypofractionated radiotherapy dose. Methods: We prospectively enrolled 103 breast cancer patients who received whole breast with or without regional nodal irradiation after breast conserving surgery using either deep inspiration breath-hold (DIBH) or free breathing (FB) radiotherapy technique. Cardiac examinations that included N-terminal pro-B-type natriuretic peptide (NT-proBNP), electrocardiogram, and myocardial perfusion imaging were performed routinely before and after radiotherapy. The effects of heart dose, systemic therapy and individual factors (Framingham score) on the incidence of cardiac events were analyzed. Results: The median age was 48 years. The mean dose (Dmean) of the heart, left anterior descending coronary artery (LAD), left ventricular (LV), and right ventricular (RV) were 4.0, 16.9, 6.3, and 4.4 Gy, respectively. With a median follow-up of 13.4 months, no patient had clinical cardiac abnormalities. The incidence rates of subclinical cardiac events at 1- 6- and 12-month were 23.5%, 31.6%, and 41.3%, respectively. The DIBH group had a lower mean dose, maximum dose, and V5-V40 in the heart, LAD, LV, and RV than the FB group (P<0.001). Univariate analysis showed an increased incidence of subclinical cardiac events with heart Dmean >4 Gy, LAD V40 > 20%, LV Dmean >6 Gy, RV Dmean >7 Gy, or cumulative doses of anthracycline or taxane > 300 mg/m(2) (All P<0.05). Anti-HER2 targeted therapy, endocrine therapy and Framingham score were not associated with the incidence of subclinical cardiac events (all P>0.05). Multivariate analysis demonstrated that Dmean of LV and RV were independently associated with the increased incidence of subclinical cardiac events. Conclusions: Early subclinical heart injury are found in patients with left-sided breast cancer after hypofractionated radiotherapy. The increased incidence of subclinical cardiac events after radiotherapy is positively associated with the cardiac radiation doses.

Osteopontin as a candidate of therapeutic application for the acute brain injury

Acute brain injury is the leading cause of human death and disability worldwide, which includes intracerebral haemorrhage, subarachnoid haemorrhage, cerebral ischaemia, traumatic brain injury and hypoxia‐ischaemia brain injury. Currently, clinical treatments for neurological dysfunction of acute brain injury have not been satisfactory. Osteopontin (OPN) is a complex adhesion protein and cytokine that interacts with multiple receptors including integrins and CD44 variants, exhibiting mostly neuroprotective roles and showing therapeutic potential for acute brain injury. OPN‐induced tissue remodelling and functional repair mainly rely on its positive roles in the coordination of pro‐inflammatory and anti‐inflammatory responses, blood‐brain barrier maintenance and anti‐apoptotic actions, as well as other mechanisms such as affecting the chemotaxis and proliferation of nerve cells. The blood OPN strongly parallel with the OPN induced in the brain and can be used as a novel biomarker of the susceptibility, severity and outcome of acute brain injury. In the present review, we summarized the molecular signalling mechanisms of OPN as well as its overall role in different kinds of acute brain injury.

CCR1 Activation Promotes Neuroinflammation Through CCR1/TPR1/ERK1/2 Signaling Pathway After Intracerebral Hemorrhage in Mice

The activation of C-C chemokine receptor type 1 (CCR1) has been shown to be pro-inflammatory in several animal models of neurological diseases. The objective of this study was to investigate the activation of CCR1 on neuroinflammation in a mouse model of intracerebral hemorrhage (ICH) and the mechanism of CCR1/tetratricopeptide repeat 1 (TPR1)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway in CCR1-mediated neuroinflammation. Adult male CD1 mice (n = 210) were used in the study. The selective CCR1 antagonist Met-RANTES was administered intranasally at 1 h after autologous blood injection. To elucidate potential mechanism, a specific ERK1/2 activator (ceramide C6) was administered prior to Met-RANTES treatment; CCR1 activator (recombinant CCL5, rCCL5) and TPR1 CRISPR were administered in naïve mouse. Neurobehavioral assessments, brain water content, immunofluorescence staining, and western blot were performed. The endogenous expressions of CCR1, CCL5, TPR1, and p-ERK1/2 were increased in the brain after ICH. CCR1 were expressed on microglia, neurons, and astrocytes. The inhibition of CCR1 with Met-RANTES improved neurologic function, decreased brain edema, and suppressed microglia/macrophage activations and neutrophil infiltration after ICH. Met-RANTES treatment decreased expressions of CCR1, TPR1, p-ERK, TNF-α, and IL-1β, which was reversed by ceramide C6. The brain CCR1 activation by rCCL5 injection in naïve mouse resulted in neurological deficits and increased expressions of CCR1, TPR1, p-ERK, TNF-α, and IL-1β. These detrimental effects of rCCL5 were reversed by TPR1 knockdown using TPR1 CRISPR. Our study demonstrated that CCR1 activation promoted neuroinflammation through CCR1/TPR1/ERK1/2 signaling pathway after ICH in mice. CCR1 inhibition with Met-RANTES attenuated neuroinflammation, thereby reducing brain edema and improving neurobehavioral functions. Targeting CCR1 activation may provide a promising therapeutic approach in the management of ICH patients.

[Association between serum levels of osteopontin and systolic pulmonary artery pressure among healthy adults post acute high altitude exposure]

Objective: To explore the association between serum levels of osteopontin (OPN) and systolic pulmonary artery pressure (sPAP) in healthy men following acute high altitude exposure. Methods: According to the inclusion and exclusion criteria, this observational study included 94 male subjects (aged from 18 to 30 years, dwelling in lowland<500 m) who ascended to Litang (4 100 m) from Chongqing (400 m) by bus with a stair-like journey within 7 days in June 2013. Data including basic information, OPN, superoxide dismutase (SOD), and malondialdehyde (MDA) and echocardiographic derived sPAP were collected within 48 hours before ascent and within 2-7 hours after arrival. Accordingly, subjects were divided into 3 groups based on the tertiles of sPAP after acute high altitude exposure: low sPAP group (26.8-32.3 mmHg (1 mmHg=0.133 kPa)) (n=31), middle sPAP group (32.4-37.4 mmHg) (n=32) and high sPAP group (37.5-55.6 mmHg) (n=31). Associations of serum OPN and SOD levels with sPAP were analysed by univariate and multivariate linear regression analysis. Results: After acute high altitude exposure, the levels of sPAP were significantly increased (P<0.001). There were no differences in age, height, weight, body mass index, percent of Han nationality and smoking among 3 subgroups. However, following acute high altitude exposure, the levels of heart rate, systolic and diastolic blood pressure elevated (all P<0.05), whereas the levels of oxygen saturation were reduced in the total subjects and all subgroups (all P<0.05). Moreover, systolic blood pressure of subjects in the high sPAP group was higher than that in low and middle sPAP groups (both P<0.05), and diastolic blood pressure of subjects in high sPAP group was higher than that in low sPAP group (P<0.05). The serum levels of OPN were increased in total cohort(27.9 (22.5,34.0) μg/L vs. 25.6 (18.4, 33.1) μg/L, P<0.05)， and high sPAP group (P<0.05), whereas no differences were found in serum SOD and MDA levels among groups. Furthermore, the serum level of OPN in high sPAP group was higher than that in low sPAP group at high altitude (P<0.05), and there was a trend for decline in SOD level with increasing sPAP (P>0.05). Results from univariable linear regression analysis showed that the serum levels of OPN (r=0.32, P=0.002) and SOD (r=-0.22，P=0.032) were linearly correlated with sPAP in total cohort after high altitude exposure. Multivariate regression analysis showed that the serum levels of OPN(β=0.310，P=0.002) and SOD (β=-0.199，P=0.043) were independently associated with the levels of sPAP at high altitude. Conclusion: After acute high altitude exposure, the serum level of OPN is positively associated with sPAP, suggesting that OPN may be a novel bio-marker for predicting the increase of pulmonary pressure in response to acute high altitude exposure.