Endoplasmic Reticulum Protein 72 Regulates Integrin Mac-1 Activity to Influence Neutrophil Recruitment.

BACKGROUND: Integrins mediate the adhesion, crawling, and migration of neutrophils during vascular inflammation. Thiol exchange is important in the regulation of integrin functions. ERp72 (endoplasmic reticulum-resident protein 72) is a member of the thiol isomerase family responsible for the catalysis of disulfide rearrangement. However, the role of ERp72 in the regulation of Mac-1 (integrin αMß2) on neutrophils remains elusive. METHODS: Intravital microscopy of the cremaster microcirculation was performed to determine in vivo neutrophil movement. Static adhesion, flow chamber, and flow cytometry were used to evaluate in vitro integrin functions. Confocal fluorescent microscopy and coimmunoprecipitation were utilized to characterize the interactions between ERp72 and Mac-1 on neutrophil surface. Cell-impermeable probes and mass spectrometry were used to label reactive thiols and identify target disulfide bonds during redox exchange. Biomembrane force probe was performed to quantitatively measure the binding affinity of Mac-1. A murine model of acute lung injury induced by lipopolysaccharide was utilized to evaluate neutrophil-associated vasculopathy. RESULTS: ERp72-deficient neutrophils exhibited increased rolling but decreased adhesion/crawling on inflamed venules in vivo and defective static adhesion in vitro. The defect was due to defective activation of integrin Mac-1 but not LFA-1 (lymphocyte function-associated antigen-1) using blocking or epitope-specific antibodies. ERp72 interacted with Mac-1 in lipid rafts on neutrophil surface leading to the reduction of the C654-C711 disulfide bond in the αM subunit that is critical for Mac-1 activation. Recombinant ERp72, via its catalytic motifs, increased the binding affinity of Mac-1 with ICAM-1 (intercellular adhesion molecule-1) and rescued the defective adhesion of ERp72-deficient neutrophils both in vitro and in vivo. Deletion of ERp72 in the bone marrow inhibited neutrophil infiltration, ameliorated tissue damage, and increased survival during murine acute lung injury. CONCLUSIONS: Extracellular ERp72 regulates integrin Mac-1 activity by catalyzing disulfide rearrangement on the αM subunit and may be a novel target for the treatment of neutrophil-associated vasculopathy.

Differential expression of FSTL1 and its correlation with the pathological process of periodontitis.

AIMS: This study aimed to elucidate the alterations in Follistatin-like protein 1 (FSTL1) and its association with the pathological process of periodontitis. METHODS: This study included 48 patients with periodontitis and 42 healthy controls. The expression level of FSTL1 in the gingiva was determined by RT-qPCR, validated using the dataset GSE16134, and subsequently examined by western blotting. Bioinformatics analysis revealed a single-cell distribution of FSTL1, characteristic of angiogenesis and immune cell infiltration. The expression and distribution of FSTL1, vascular endothelial marker protein CD31 and myeloperoxidase (MPO), the indicator of neutrophil activity, were determined by immunohistochemistry (IHC). A series of correlation analyses was performed to determine the associations between FSTL1 and clinical parameters, including probing depth (PD) and clinical attachment loss (CAL), and their potential role in angiogenesis (CD31) and neutrophil infiltration (MPO). RESULTS: FSTL1 was significantly upregulated in the gingiva of patients with periodontitis compared to their healthy counterparts. In addition, FSTL1 was positively correlated with the clinical parameters PD (r = .5971, p = .0005) and CAL (r = .6078, p = .0004). Bioinformatic analysis and IHC indicated that high FSTL1 expression was significantly correlated with angiogenesis and neutrophil infiltration in periodontitis. Moreover, receiver operating characteristic (ROC) analysis demonstrated that FSTL1 could serve as an independent indicator for evaluating the severity of periodontitis (area under the curve [AUC] = 0.9011, p < .0001). CONCLUSION: This study demonstrated FSTL1 upregulation in periodontitis and its potential contribution to the disease via angiogenesis and neutrophil infiltration.

Esculetin facilitates post-stroke rehabilitation by inhibiting CKLF1-mediated neutrophil infiltration.

Esculetin (ESC) is a coumarin-derived phytochemical prevalent in traditional Chinese medicine that exhibits anti-acute ischemic stroke activities. Our previous studies demonstrate that CKLF1 is a potential anti-stroke target for coumarin-derived compound. In this study we investigated whether CKLF1 was involved in the neuroprotective effects of ESC against photothrombotic stroke in mice. The mice were treated with ESC (20, 40 or 80 mg·kg-1·d-1, i.g.) for two weeks. The therapeutic effect of ESC was assessed using MRI, neurological function evaluation, and a range of behavioral tests on D1, 3, 7 and 14 of ESC administration. We showed that oral administration of ESC dose-dependently reduced the cerebral infarction volume within one week after stroke, improved behavioral performance, and alleviated neuropathological damage within two weeks. Functional MRI revealed that ESC significantly enhanced the abnormal low-frequency fluctuation (ALFF) value of the motor cortex and promoted functional connectivity between the supplementary motor area (SMA) and multiple brain regions. We demonstrated that ESC significantly reduced the protein levels of CKLF1 and CCR5, as well as the CKLF1/CCR5 protein complex in the peri-infarcted area. We showed that ESC (0.1-10 µM) dose-dependently blocked CKLF1-induced chemotactic movement of neutrophils in the Transwell assay, reducing the interaction of CKLF1/CCR5 on the surface of neutrophils, thereby reducing neutrophil infiltration, and decreasing the expression of ICAM-1, VCAM-1 and MMP-9 in the peri-infarct tissue. Knockout of CKLF1 reduced brain infarction volume and motor dysfunction after stroke but also negated the anti-stroke efficacy and neutrophil infiltration of ESC. These results suggest that the efficacy of ESC in promoting post-stroke neural repair depends on its inhibition on CKLF1-mediated neutrophil infiltration, which offering novel perspectives for elucidating the therapeutic properties of coumarins.

Dexmedetomidine postconditioning alleviates spinal cord ischemia-reperfusion injury in rats via inhibiting neutrophil infiltration, microglia activation, reactive gliosis and CXCL13/CXCR5 axis activation.

PURPOSE: Spinal cord ischemia-reperfusion (I/R) injury is an unresolved complication and its mechanisms are still not completely understood. Here, we studied the neuroprotective effects of dexmedetomidine (DEX) postconditioning against spinal cord I/R injury in rats and explored the possible mechanisms. MATERIALS AND METHODS: In the study, rats were randomly divided into five groups: sham group, I/R group, DEX0.5 group, DEX2.5 group, and DEX5 group. I/R injury was induced in experimental rats; 0.5 µg/kg, 2.5 µg/kg, 5 µg/kg DEX were intravenously injected upon reperfusion respectively. Neurological function, histological assessment, and the disruption of blood-spinal cord barrier (BSCB) were evaluated via the BBB scoring, hematoxylin and eosin staining, Evans Blue (EB) extravasation and spinal cord edema, respectively. Neutrophil infiltration was evaluated via Myeloperoxidase (MPO) activity. Microglia activation and reactive gliosis was evaluated via ionized calcium-binding adapter molecule-1(IBA-1) and glial fibrillary acidic protein (GFAP) immunofluorescence, respectively. The expression of C-X-C motif ligand 13 (CXCL13), C-X-C chemokine receptor type 5(CXCR5), caspase-3 was determined by western blotting. The expression levels of interleukin 6(IL-6), tumor necrosis factor-α(TNF-α), IL-1ß were determined by ELISA assay. RESULTS: DEX postconditioning preserved neurological assessment scores, improved histological assessment scores, attenuated BSCB leakage after spinal cord I/R injury. Neutrophil infiltration, microglia activation and reactive gliosis were also inhibited by DEX postconditioning. The expression of CXCL13, CXCR5, caspase-3, IL-6, TNF-α, IL-1ß were reduced by DEX postconditioning. CONCLUSIONS: DEX postconditioning alleviated spinal cord I/R injury, which might be mediated via inhibition of neutrophil infiltration, microglia activation, reactive gliosis and CXCL13/CXCR5 axis activation.

Amniotic Mesenchymal-Derived Extracellular Vesicles and Their Role in the Prevention of Persistent Post-Breeding Induced Endometritis.

Persistent post-breeding induced endometritis (PPBIE) is considered a major cause of subfertility in mares. It consists of persistent or delayed uterine inflammation in susceptible mares. There are many options for the treatment of PPBIE, but in this study, a novel approach aimed at preventing the onset of PPBIE was investigated. Stallion semen was supplemented with extracellular vesicles derived from amniotic mesenchymal stromal cells (AMSC-EVs) at the time of insemination to prevent or limit the development of PPBIE. Before use in mares, a dose-response curve was produced to evaluate the effect of AMSC-EVs on spermatozoa, and an optimal concentration of 400 × 106 EVs with 10 × 106 spermatozoa/mL was identified. At this concentration, sperm mobility parameters were not negatively affected. Sixteen susceptible mares were enrolled and inseminated with semen (n = 8; control group) or with semen supplemented with EVs (n = 8; EV group). The supplementation of AMSC-EVs to semen resulted in a reduction in polymorphonuclear neutrophil (PMN) infiltration as well as intrauterine fluid accumulation (IUF; p < 0.05). There was a significant reduction in intrauterine cytokine levels (p < 0.05) for TNF-α and IL-6 and an increase in anti-inflammatory IL-10 in mares in the EV group, suggesting successful modulation of the post-insemination inflammatory response. This procedure may be useful for mares susceptible to PPBIE.

Deficiency of Acute-Phase Serum Amyloid A Exacerbates Sepsis-Induced Mortality and Lung Injury in Mice.

Serum amyloid A (SAA) is a family of proteins, the plasma levels of which may increase >1000-fold in acute inflammatory states. We investigated the role of SAA in sepsis using mice deficient in all three acute-phase SAA isoforms (SAA-TKO). SAA deficiency significantly increased mortality rates in the three experimental sepsis mouse models: cecal ligation and puncture (CLP), cecal slurry (CS) injection, and lipopolysaccharide (LPS) treatments. SAA-TKO mice had exacerbated lung pathology compared to wild-type (WT) mice after CLP. A bulk RNA sequencing performed on lung tissues excised 24 h after CLP indicated significant enrichment in the expression of genes associated with chemokine production, chemokine and cytokine-mediated signaling, neutrophil chemotaxis, and neutrophil migration in SAA-TKO compared to WT mice. Consistently, myeloperoxidase activity and neutrophil counts were significantly increased in the lungs of septic SAA-TKO mice compared to WT mice. The in vitro treatment of HL-60, neutrophil-like cells, with SAA or SAA bound to a high-density lipoprotein (SAA-HDL), significantly decreased cellular transmigration through laminin-coated membranes compared to untreated cells. Thus, SAA potentially prevents neutrophil transmigration into injured lungs, thus reducing exacerbated tissue injury and mortality. In conclusion, we demonstrate for the first time that endogenous SAA plays a protective role in sepsis, including ameliorating lung injury.

Aspirin-Triggered Resolvin D1 (AT-RvD1) Protects Mouse Skin against UVB-Induced Inflammation and Oxidative Stress.

Intense exposure to UVB radiation incites excessive production of reactive oxygen species (ROS) and inflammation. The resolution of inflammation is an active process orchestrated by a family of lipid molecules that includes AT-RvD1, a specialized proresolving lipid mediator (SPM). AT-RvD1 is derived from omega-3, which presents anti-inflammatory activity and reduces oxidative stress markers. The present work aims to investigate the protective effect of AT-RvD1 on UVB-induced inflammation and oxidative stress in hairless mice. Animals were first treated with 30, 100, and 300 pg/animal AT-RvD1 (i.v.) and then exposed to UVB (4.14 J/cm2). The results showed that 300 pg/animal of AT-RvD1 could restrict skin edema, neutrophil and mast cell infiltration, COX-2 mRNA expression, cytokine release, and MMP-9 activity and restore skin antioxidant capacity as per FRAP and ABTS assays and control O2•- production, lipoperoxidation, epidermal thickening, and sunburn cells development. AT-RvD1 could reverse the UVB-induced downregulation of Nrf2 and its downstream targets GSH, catalase, and NOQ-1. Our results suggest that by upregulating the Nrf2 pathway, AT-RvD1 promotes the expression of ARE genes, restoring the skin's natural antioxidant defense against UVB exposition to avoid oxidative stress, inflammation, and tissue damage.

Targeted BRD4 protein degradation by dBET1 ameliorates acute ischemic brain injury and improves functional outcomes associated with reduced neuroinflammation and oxidative stress and preservation of blood-brain barrier integrity.

Bromodomain-containing protein 4 (BRD4), a member of the bromodomain and extra-terminal domain (BET) protein family, plays a crucial role in regulating inflammation and oxidative stress that are tightly related to stroke development and progression. Consequently, BRD4 blockade has attracted increasing interest for associated neurological diseases, including stroke. dBET1 is a novel and effective BRD4 degrader through the proteolysis-targeting chimera (PROTAC) strategy. We hypothesized that dBET1 protects against brain damage and neurological deficits in a transient focal ischemic stroke mouse model by reducing inflammation and oxidative stress and preserving the blood-brain barrier (BBB) integrity. Post-ischemic dBET1 treatment starting 4 h after stroke onset significantly ameliorated severe neurological deficits and reduced infarct volume 48 h after stroke. dBET1 markedly reduced inflammation and oxidative stress after stroke, indicated by multiple pro-inflammatory cytokines and chemokines including IL-1ß, IL-6, TNF-α, CCL2, CXCL1 and CXCL10, and oxidative damage markers 4-hydroxynonenal (4-HNE) and gp91phox and antioxidative proteins SOD2 and GPx1. Meanwhile, stroke-induced BBB disruption, increased MMP-9 levels, neutrophil infiltration, and increased ICAM-1 were significantly attenuated by dBET1 treatment. Post-ischemic dBET1 administration also attenuated ischemia-induced reactive gliosis in microglia and astrocytes. Overall, these findings demonstrate that BRD4 degradation by dBET1 improves acute stroke outcomes, which is associated with reduced neuroinflammation and oxidative stress and preservation of BBB integrity. This study identifies a novel role of BET proteins in the mechanisms resulting in ischemic brain damage, which can be leveraged to develop novel therapies.

Antitumor efficacy of CRISPR/Cas9-engineered ICP6 mutant herpes simplex viruses in a mouse xenograft model for lung adenocarcinoma.

Oncolytic viruses (OVs), including oncolytic herpes simplex viruses (oHSVs), are promising therapeutics against cancer. Here, we report two ICP6-mutated HSVs (type I) generated by CRISPR/Cas9, rHSV1/∆RR (with ICP6 ribonucleotide reductase [RR] domain deleted) and rHSV1/∆ICP6 (with a complete deletion of ICP6), exhibiting potent antitumor efficacy against lung adenocarcinoma. Both the mutants showed strong cytotoxicity in vitro, comparable with the control viruses expressing intact ICP6, but in relatively lower titers. Moreover, these mutant viruses exhibited preferential killing ability against lung tumor cells rather than normal lung fibroblast cells. Further, unlike the control HSV-1 causing severe illness or death in the mouse model, the ICP6-mutated viruses did not induce significant pathogenicity but instead effectively reduced tumor burden in vivo and led to 100% survival of the animals, indicating notable antitumor activity and attenuated virulence. In addition, rHSV1/∆RR seemed to have even better antitumor efficacy than rHSV1/∆ICP6, albeit no statistical significance in inhibition of tumor volume. Histopathologically, rHSV1/∆RR induced massive neutrophil infiltration to the tumor microenvironment and consistently, triggered more antitumor immune and neutrophil chemotactic cytokines or higher expression levels of them (indicated by quantitative polymerase chain reaction and transcriptome analyses). These results demonstrate the anti-adenocarcinoma potential of the CRISPR/Cas9-engineered ICP6 mutant HSV1, especially the rHSV1/∆RR, which likely induces stronger innate antitumor immune response. Together, these findings may provide new valuable clues for further development of OV-based therapeutics against lung adenocarcinoma or other types of tumors.

IL-17 exacerbates experimental autoimmune prostatitis via CXCL1/CXCL2-mediated neutrophil infiltration.

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a poorly understood disease. Accumulating evidence suggests that autoimmune dysfunction is involved in the development of CP/CPPS. Interleukin-17 (IL-17) is associated with the occurrence and development of several chronic autoimmune inflammatory diseases. However, the molecular mechanisms underlying the role of IL-17 in CP/CPPS are not clear. We confirmed that IL-17 was increased in the prostate tissues of experimental autoimmune prostatitis (EAP) mice. Corresponding to the increase of IL-17, neutrophil infiltration and the levels of CXCL1 and CXCL2 (CXC chemokine ligands 1 and 2) were also increased in the prostate of EAP. Treatment of EAP mice with an IL-17-neutralizing monoclonal antibody (mAb) decreased the number of infiltrated neutrophils and CXCL1 and CXCL2 levels. Depletion of neutrophils using anti-Ly6G antibodies ameliorated the inflammatory changes and hyperalgesia caused by EAP. Fucoidan, a could potent inhibitor of neutrophil migration, also ameliorate the manifestations of EAP. Our findings suggested that IL-17 promoted the production of CXCL1 and CXCL2, which triggered neutrophil chemotaxis to prostate tissues. Fucoidan might be a potential drug for the treatment of EAP via the effective inhibition of neutrophil infiltration.

Twin-Arginine Translocation System Is Involved in Citrobacter rodentium Fitness in the Intestinal Tract.

The twin-arginine translocation (Tat) system is involved in not only a wide array of cellular processes but also pathogenesis in many bacterial pathogens; thus, this system is expected to become a novel therapeutic target to treat infections. To the best of our knowledge, involvement of the Tat system has not been reported in the gut infection caused by Citrobacter rodentium Here, we studied the role of Tat in C. rodentium gut infection, which resembles human infection with enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). A C. rodentium Tat loss-of-function mutant displayed prolonged gut colonization, which was explained by reduced inflammatory responses and, particularly, neutrophil infiltration. Further, the Tat mutant had colonization defects upon coinfection with the wild-type strain of C. rodentium The Tat mutant also became hypersensitive to bile acids, and an increase in fecal bile acids fostered C. rodentium clearance from the gut lumen. Finally, we show that the chain form of C. rodentium cells, induced by a Tat-dependent cell division defect, exhibits impaired resistance to bile acids. Our findings indicate that the Tat system is involved in gut colonization by C. rodentium, which is associated with neutrophil infiltration and resistance to bile acids. Interventions that target the Tat system, as well as luminal bile acids, might thus be promising therapeutic strategies to treat human EHEC and EPEC infections.

Cerumen impaction was composed of abnormal exfoliation of keratinocytes that was correlated with infection.

OBJECTIVE: This study investigated the exact composition and tried to be helpful in explaining the etiologic mechanism of cerumen impaction in the external auditory canal (EAC). METHODS: A hundred impacted cerumen samples and 15 normal cerumen samples were collected by manual removal and divided into 2 groups. All samples were examined via microbial culture, hematoxylin-eosin staining, periodic acid-Schiff staining, and fungal fluorescent staining. RESULTS: Eighty-eight patients in group 1 were in the habit of using cotton buds. Forty-seven impacted cerumen samples tested positive for microbes, while only 1 sample of normal cerumen tested positive for microbes (p < .05). The most commonly isolated bacterium and fungus was Staphylococcus aureus and Aspergillus terreus respectively. All cerumen samples were composed of exfoliated keratinocytes and microorganisms assessed via pathologic examination. However, unlike normal cerumen, impacted cerumen contained nucleated keratinocytes and infiltrated neutrophils. Recurrent impaction was found only among patients who tested mold culture-positive. CONCLUSION: Impacted cerumen is composed of abnormal exfoliated keratinocytes that was correlated with microbial-induced neutrophil-mediated inflammation. Mold infection is highly correlated with recurrent cerumen impaction. Microbial culture of removed impacted cerumen is strongly recommended. Ear cleaning with cotton buds, particularly when the EAC is wet might be one of the important causes of cerumen impaction which is need further studied. LEVEL OF EVIDENCE: 2b.

Glycomacropeptide Ameliorates Indomethacin-Induced Enteropathy in Rats by Modifying Intestinal Inflammation and Oxidative Stress.

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy is considered a serious and increasing clinical problem without available treatment. Glycomacropeptide (GMP) is a 64-amino acid peptide derived from milk κ-casein with numerous biological activities. The aim of this study was to investigate the protective effect of GMP on NSAID enteropathy in rats. Enteropathy was induced by seven days oral indomethacin administration. Rats were orally GMP treated from seven days previous and during the establishment of the enteropathy model. Changes in metabolism, hematological and biochemical blood alterations, intestinal inflammation and oxidative damage were analyzed. Integrity barrier markers, macroscopic intestinal damage and survival rate were also evaluated. GMP treatment prevented anorexia and weight loss in animals. Furthermore, prophylaxis with GMP ameliorated the decline in hemoglobin, hematocrit, albumin and total protein levels. The treatment had no therapeutic efficacy on the decrease of occludin and mucin (MUC)-2 expression in intestinal tissue. However, GMP markedly decreased neutrophil infiltration, and CXCL1, interleukin-1ß and inducible nitric oxide synthase expression. Nitric oxide production and lipid hydroperoxide level in the small intestine were also diminished. These beneficial effects were mirrored by preventing ulcer development and increasing animal survival. These results suggest that GMP may protect against NSAID enteropathy through anti-inflammatory and antioxidant properties.

LL-37 and its analog FF/CAP18 attenuate neutrophil migration in sepsis-induced acute lung injury.

INTRODUCTION: Sepsis can result in acute lung injury. LL-37 is a small cationic host defense peptide involved in anti-inflammatory. In the current study, it was hypothesized that antimicrobial peptide LL-37 could play a protective role in attenuating the progression of sepsis-induced acute lung injury. METHODS: Forty male C57BL/6 mice were induced into sepsis using cecal ligation and puncture, and subsequently administered with recombinant mouse osteopontin. Peptides LL-37, the LL-37 analog (FF/CAP18, called sLL-37), or normal saline was intravenously administered into septic mice for 20 hours. Then, proinflammatory cytokines (IL-6 and IL-1ß), acute lung injury markers (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and lactate dehydrogenase [LDH]), the neutrophil infiltration marker (myeloperoxidase [MPO]), and neutrophil infiltration were detected. Furthermore, the neutrophil migration and expression of migration-related factors (focal adhesion kinase [FAK], ERK, and P38) in differentiated HL-60 cells were detected. RESULTS: Septic mice had upregulated IL-6, IL-1ß, ALT, AST, LDH, MPO, p-FAK, p-ERK, and p-P38, infiltrated neutrophils, and migrated neutrophil-like HL-60 cells. In contrast, the administration of peptide LL-37 and sLL-37 inhibited all these changes. Compared with septic mice, it was found that proinflammatory cytokines, lung injury markers, MPO, and infiltrated neutrophils decreased in mice treated with LL-37 and sLL-37. In addition, the migrated neutrophil-like HL-60 cells and activated p-FAK, p-ERK, and p-P38 proteins were suppressed by LL-37 and sLL-37 treatments. CONCLUSIONS: Peptide LL-37 and its analog sLL-37 attenuated the progression of sepsis-induced acute lung injury by inhibiting neutrophil infiltration and migration through the FAK, ERK, and P38 pathways.

IL-33/ST2 plays a critical role in endothelial cell activation and microglia-mediated neuroinflammation modulation.

BACKGROUND: Interleukin-33 (IL-33) is increasingly being recognized as a key immunomodulatory cytokine in many neurological diseases. METHODS: In the present study, wild-type (WT) and IL-33-/- mice received intracerebroventricular (i.c.v.) injection of lipopolysaccharide (LPS) to induce neuroinflammation. Intravital microscopy was employed to examine leukocyte-endothelial interactions in the brain vasculature. The degree of neutrophil infiltration was determined by myeloperoxidase (MPO) staining. Real-time PCR and western blotting were used to detect endothelial activation. Enzyme-linked immunosorbent assay and quantitative PCR were conducted to detect pro-inflammatory cytokine levels in the brain. RESULTS: In IL-33-/- mice, neutrophil infiltration in the brain cortex and leukocyte-endothelial cell interactions in the cerebral microvessels were significantly decreased as compared to WT mice after LPS injection. In addition, IL-33-/- mice showed reduced activation of microglia and cerebral endothelial cells. In vitro results indicated that IL-33 directly activated cerebral endothelial cells and promoted pro-inflammatory cytokine production in LPS-stimulated microglia. CONCLUSIONS: Our study indicated that IL-33/ST2 signaling plays an important role in the activation of microglia and cerebral endothelial cells and, therefore, is essential in leukocyte recruitment in brain inflammation. The role of IL-33/ST2 in LPS induced neuroinflammation.

Development of psoriasis by continuous neutrophil infiltration into the epidermis.

Remarkable effects of anti-IL-17A and anti-IL-23 antibodies on psoriasis indicate deep involvement of IL-23/Th17 axis in the pathogenesis of psoriasis. According to the current immune theory, activation of dendritic cells initiates the generation of this axis. However, this theory is not enough to explain the mechanism, because the process of this activation is obscure and the antigen that is recognized by antigen-presenting cells and pathogenic T cells has long been unidentified. Therefore, I thought of another theory as follows. Neutrophils are attracted by LTB4 at subcorneal portion and infiltrate into the epidermis. At the time of neutrophil migration through the basement membrane, basal keratinocytes in G0/G1 phase enter the cell cycle and begin to proliferate, according to the principle, "detachment-mediated cell proliferation." This passing is continuously repeated and leads to elongation of rete ridges. The IL-23/Th17 axis is generated by interactions between infiltrated neutrophils and keratinocytes. Briefly, neutrophils infiltrated into the epidermis secrete IL-17A, which acts on keratinocytes to express CCL20, a ligand for the chemokine receptor CCR6. Keratinocytes perturbed by neutrophil infiltration produce HSP70, followed by production of IL-23 via TLR4 using HSP70 as an endogenous ligand for TLR4. Natural Th17 cells expressing CCR6 are recruited to psoriatic epidermis and expand there in the presence of IL-23 and IL-1ß. In this manner, the framework of the IL-23/Th17 axis is created, which acts to maintain or exacerbate psoriasis. Noteworthy is the fact that this axis causes positive feedback loop, starting from IL-17A production by neutrophils and ending in IL-17A production by nTh17 cells. Therapeutic mechanisms of anti-IL-17A and anti-IL-23 antibodies, targeting neutrophils, were also described.

Possible anti-inflammatory role of Zingiberis processum rhizoma, one component of the Kampo formula daikenchuto, against neutrophil infiltration through muscarinic acetylcholine receptor activation.

Zingiberis processum rhizoma (ZPR) is a major active component of daikenchuto (DKT), which induces anti-inflammatory action by inhibiting macrophage infiltration. However, it is unclear whether ZPR is related to DKT-induced anti-inflammatory action via a reduction of neutrophil infiltration against postoperative ileus (POI). In this study, we orally administered individual herbal components of DKT to mice four times before and after intestinal manipulation (IM). The anti-inflammatory action of each crude drug was evaluated by histochemical analysis of relevant molecules. The results showed that treatment with all herbal components of DKT significantly inhibits neutrophil infiltration. This inhibition of neutrophil infiltration by ZPR was significantly reduced in 5-hydroxytryptamine receptor 4 (5-HT4R) knockout (KO) mice but not in alpha-7 nicotinic acetylcholine receptor (α7nAChR) KO mice. Also, transient receptor potential ankyrin 1 (TRPA1) and muscarinic acetylcholine receptor (mAChR) antagonists partly and significantly inhibited the amelioration of neutrophil infiltration by ZPR. Therefore, DKT-induced anti-inflammatory action, mediated by inhibition of neutrophil infiltration in POI, depends, in part, on the effects of ZPR. ZPR activates TRPA1 channels, possibly in enterochromaffin (EC) cells, to release 5-HT. This 5-HT stimulates 5-HT4R in the myenteric plexus neurons to release acetylcholine, which, in turn, activates mAChR to inhibit inflammation in POI.

Combined but not single administration of vitamin C and l-carnitine ameliorates cisplatin-induced gastric mucosa damage in male rats.

Although cisplatin is a potent anticancer drug, it instigates oxidative and pro-inflammatory reactions that pose significant and distressing clinical symptoms. Therefore, this study investigated the effects of vitamin C and (or) l-carnitine on cisplatin-induced gastric mucosa damage in rat. The rats were allocated into 6 groups (n = 5). The control group received distilled water, while the treatment groups received cisplatin alone (CIP), or cisplatin with vitamin C, l-carnitine, or their combination. Cisplatin caused disruption of the gastric mucosa histoarchitecture and altered the mucus barrier function. Moreover, the stomach tissue of the CIP-treated group showed increased levels of oxidative stress markers (malondialdehyde and H2O2) and decreased activities of antioxidant (superoxide dismutase, glutathione peroxidase, catalase, glutathione S-transferase) and non-antioxidant (reduced glutathione) enzymes. These deleterious events were accompanied with significant increases in pro-inflammatory cytokines and inflammatory infiltration markers, myeloperoxidase and inducible nitric oxide synthase. However, the administration of both vitamin C and l-carnitine, and not either of the two showed additive effects in attenuating the adverse effects of cisplatin. The histological results agreed with the biochemical assays. The study concluded that the combined administration of vitamin C and l-carnitine, but not the single therapy, could prevent the adverse effects of cisplatin on gastric tissue.

Novel Proinflammatory Function of Renal Intercalated Cells.

BACKGROUND: Serious and often fatal acute kidney injury (AKI) is frequently seen after major surgery, local and remote organ damage, and sepsis. It is associated with uncontrolled inflammation, and is usually diagnosed only after the kidneys have gone through significant and often irreversible damage. SUMMARY: During our work involving another type of kidney disease that leads to acid-base disorders of the blood, we unexpectedly found high levels of a protein called the P2Y14 "purinergic" receptor, in specialized kidney epithelial cells called intercalated cells (ICs). These cells are responsible for maintaining whole body acid-base balance by regulating the secretion of excess protons into the urine, which normalizes blood pH. However, it turns out that the P2Y14 receptor in these cells responds to a molecule called uridine diphosphate (UDP)-glucose, which is a danger signal released by damaged cells anywhere in the body. When UDP-glucose reaches the kidney, it stimulates ICs to produce chemoattractant cytokines; this results in renal inflammation and contributes to the onset of AKI. Key Message: Thus, our work now points to ICs as key mediators of renal inflammation and AKI, following surgery and/or damage to remote organs, sepsis, and also local insults to the kidney itself. The link between the proton secreting ICs of the kidney and AKI is an example of how a fundamental research project with a defined aim, in this case understanding acid-base homeostasis, can lead to a novel observation that has unexpected but major implications in another area of human health.

Compound 48/80, a mast cell degranulator, causes oxidative damage by enhancing vitamin C synthesis via reduced glutathione depletion and lipid peroxidation through neutrophil infiltration in rat livers.

In this study, we examined whether compound 48/80 (C48/80), a mast cell degranulator, causes hepatic oxidative damage in rats. Serum and liver biochemical parameters were determined 0.5, 3 or 6 h after a single treatment with C48/80 (0.75 mg/kg). Serum histamine and serotonin levels increased 0.5 h after C48/80 treatment but diminished thereafter. Increases in serum vitamin C (VC) and transaminases and hepatic hydrogen peroxide, lipid peroxide, and myeloperoxidase levels and a decrease in hepatic reduced glutathione level occurred 0.5 h after C48/80 treatment and further proceeded at 3 h, but these changes diminished at 6 h. Serum lipid peroxide and hepatic VC levels increased 3 h after C48/80 treatment. Hepatic glycogen level decreased 0.5 h after C48/80 treatment and further decreased at 3 h. Pre-administered ketotifen diminished all these changes found at 3 h after treatment, while pre-administered NPC 14686 diminished these changes except changes in serum histamine and serotonin levels. Hepatocellular apoptosis observed at 3 h after C48/80 treatment was attenuated by pre-administered ketotifen and NPC 14686. These results indicate that C48/80 causes oxidative damage by enhancing VC synthesis via reduced glutathione depletion-dependent glycogenolysis and lipid peroxidation through neutrophil infiltration following mast cell degranulation in rat livers.