Unveiling the biological role of sphingosine-1-phosphate receptor modulators in inflammatory bowel diseases

Inflammatory bowel disease(IBD)is chronic inflammation of the gastrointestinal tract that has a high epidemiological prevalence worldwide.The increasing disease burden worldwide,lack of response to current biologic therapeutics,and treatment-related immunogenicity have led to major concerns regarding the clinical management of IBD patients and treatment efficacy.Understanding disease pathogenesis and disease-related molecular mechanisms is the most important goal in developing new and effective therapeutics.Sphingosine-1-phosphate(S1P)receptor(S1PR)modulators form a class of oral small molecule drugs currently in clinical development for IBD have shown promising effects on disease improvement.S1P is a sphingosine-derived phospholipid that acts by binding to its receptor S1PR and is involved in the regulation of several biological processes including cell survival,differentiation,migration,proliferation,immune response,and lymphocyte trafficking.T lymphocytes play an important role in regulating inflammatory responses.In inflamed IBD tissue,an imbalance between T helper(Th)and regulatory T lymphocytes and Th cytokine levels was found.The S1P/S1PR signaling axis and metabolism have been linked to inflammatory responses in IBD.S1P modulators targeting S1PRs and S1P metabolism have been developed and shown to regulate inflammatory responses by affecting lymphocyte trafficking,lymphocyte number,lymphocyte activity,cytokine production,and contributing to gut barrier function.

STAT3 and sphingosine-1-phosphate in inflammation-associated colorectal cancer

Accumulated evidences have demonstrated that signal transducer and activator of transcription 3(STAT3)is a critical link between inflammation and cancer.Multiple studies have indicated that persistent activation of STAT3 in epithelial/tumor cells in inflammation-associated colorectal cancer(CRC)is associated with sphingosine-1-phosphate(S1P)receptor signaling.In inflammatory response whereby interleukin(IL)-6 production is abundant,STAT3-mediated pathways were found to promote the activation of sphingosine kinases(SphK1and SphK2)leading to the production of S1P.Reciprocally,S1P encourages the activation of STAT3 through a positive autocrine-loop signaling.The crosstalk between IL-6,STAT3 and sphingolipid regulated pathways may play an essential role in tumorigenesis and tumor progression in inflamed intestines.Therapeutics targeting both STAT3 and sphingolipid are therefore likely to contribute novel and more effective therapeutic strategies against inflammation-associated CRC.

Sphingosine-1-phosphate signaling in vasculogenesis and angiogenesis

Blood vessels either form de novo through the process of vasculogenesis or through angiogenesis that involves the sprouting and proliferation of endothelial cells in pre-existing blood vessels. A complex interactive network of signaling cascades downstream from at least three of the nine known G-protein-coupled sphingosine-1-phosphate (S1P) receptors act as a prime effector of neovascularization that occurs in embryonic development and in association with various pathologies. This review focuses on the current knowledge of the roles of S1P signaling in vasculogenesis and angiogenesis, with particular emphasis on vascular cell adhesion and motility responses.

Roles of sphingosine-1-phosphate signaling in angiogenesis

Sphingosine-1-phosphate (S1P) is a blood-borne lipid mediator with pleiotropic biological activities. S1P acts via the specific cell surface G-protein-coupled receptors, S1P1-5. S1P1 and S1P2 were originally identified from vascular endothelial cells (ECs) and smooth muscle cells, respectively. Emerging evidence shows that S1P plays crucial roles in the regulation of vascular functions, including vascular formation, barrier protection and vascular tone via S1P1, S1P2 and S1P3. In particular, S1P regulates vascular formation through multiple mechanisms; S1P exerts both positive and negative effects on angiogenesis and vascular maturation. The positive and negative effects of S1P are mediated by S1P1 and S1P2, respectively. These effects of S1P1 and S1P2 are probably mediated by the S1P receptors expressed in multiple cell types including ECs and bone-marrow-derived cells. The receptor-subtype-specific, distinct effects ofS1P favor the development of novel therapeutic tactics for antitumor angiogenesis in cancer and therapeutic angiogenesis in ischemic diseases.

Role of sphingosine kinase and sphingosine-1-phosphate in inflammatory arthritis

The importance of sphingosine kinase(SphK)and sphingosine-1-phosphate(S1P)in inflammation has been extensively demonstrated.As an intracellular second messenger,S1P plays an important role in calcium signaling and mobilization,and cell proliferation and survival.Activation of various plasma membrane receptors,such as the formyl methionyl leucyl phenylalanine receptor,C5a receptor,and tumor necrosis factor α receptor,leads to a rapid increase in intracellular S1P level via SphK stimulation.SphK and S1P are implicated in various chronic autoimmune conditions such as rheumatoid arthritis, primary Sjgren's syndrome,and inflammatory bowel disease.Recent studies have demonstrated the important role of SphK and S1P in the development of arthritis by regulating the pro-inflammatory responses.These novel pathways represent exciting potential therapeutic targets.

Regulatory role of sphingosine kinase and sphingosine-1-phosphate receptor signaling in progenitor/stem cells

Balanced sphingolipid signaling is important for the maintenance of homeostasis. Sphingolipids were demonstrated to function as structural components, second messengers, and regulators of cell growth and survival in normal and disease-affected tissues. Particularly, sphingosine kinase 1 (SphK1) and its product sphingosine-1-phosphate (S1P) operate as mediators and facilitators of proliferation-linked signaling. Unlimited proliferation (selfrenewal) within the regulated environment is a hallmark of progenitor/stem cells that was recently associated with the S1P signaling network in vasculature, nervous,muscular, and immune systems. S1P was shown to regulate progenitor-related characteristics in normal and cancerstemcells(CSCs) viaG-protein coupled receptorsS1Pn(n=1 to 5). The SphK/S1P axis is crucially involved in the regulation of embryonic development of vasculature and the nervous system, hematopoietic stem cell migration, regeneration of skeletal muscle, and development of multiple sclerosis. The ratio of the S1P receptor expression, localization, and specific S1P receptoractivated downstream effectors influenced the rate of selfrenewal and should be further explored as regeneration related targets. Considering malignant transformation,it is essential to control the level of self-renewal capacity.Proliferation of the progenitor cell should be synchronized with differentiation to provide healthy lifelong function of blood, immune systems, and replacement of damaged ordead cells. The differentiation-related role of SphK/S1P remains poorly assessed. A few pioneering investigations exploredpharmacologicaltoolsthattargetsphingolipid signaling and can potentially confine and direct self-renewal towards normal differentiation. Further investigation is required to test the role of the SphK/S1P axis in regulation of self-renewal and differentiation.

Sphingosine-1-Phosphate Protects Against the Development of Cardiac Remodeling via Sphingosine Kinase 2 and the S1PR2/ERK Pathway

Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac protection.Our previous work found that sphingosine-1-phosphate(S1P)could ameliorate cardiac hypertrophy.In this study,we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.Methods:Eight-week-old male C57BL/6 mice were randomly divided into a sham,transverse aortic constriction(TAC)or a TAC+S1P treatment group.Results:We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease inα-smooth muscle actin(α-SMA)and collagen type I(COL I)expression compared with the TAC group.We also found that one of the key S1P enzymes,sphingosine kinase 2(SphK2),which was mainly distributed in cytoblasts,was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro.In addition,our in vitro results showed that S1P treatment activated extracellular regulated protein kinases(ERK)phosphorylation mainly through the S1P receptor 2(S1PR2)and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.Conclusion:These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart.This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.

Expressions of Sphingosine-1-phosphate (S1P) Receptors, Sphingosine Kinases in Malignant Bone and Soft Tissue Tumors, and The role of Sphingosine Kinase-1 in Growth of MFH Cell Lines

Sphingolipids are ubiquitous components of cell membranes. Their metabolites ceramide, sphingosine, and sphingosine-1-phosphate (S1P) have important physiological functions, including regulation of cell growth and survival. S1P is generated by phosphorylation of sphingosine catalyzed by sphingosine kinase-1 (SPHK1). The purpose of this study is to explore the roles of S1P, S1P receptors, and sphingosine kinases in malignant musculoskeletal tumors. Twenty-one tumor samples (7 liposarcomas, 3 chondrosarcomas, 6 osteosarcomas, 5 MFH) obtained at open biopsy, and four human MFH cell lines (Nara H, Nara F, TNMY1, GBS-1) were used. We examined the mRNA expression of S1P receptors by RT-PCR, and the expression levels of SPHK by Real-time PCR. We used 4 MFH cell lines to analyze SPHK1 proteins by Western blotting. SPHK1 siRNA was transfected into MFH cell lines by lipofection method. Cell proliferation (control and transfected with siRNA) was assayed using WST-8 (Cell Counting Kit-8) assay. All high grade malignant tumors expressed S1P1, S1P2, S1P3 receptors, whereas the expression of S1P1 receptor was detected in 50% of low-grade malignant tumors, S1P2 receptor in 30%, and S1P3 in 50%. No statistically significant difference was found in the expression level of SPHK1 between high-grade and low-grade malignant tumors by Real-time PCR. By results of Western blotting, proteins of SPHK1 were expressed in all MFH cell lines. In MFH cell lines, transfection with SPHK1 siRNA oligonucleotides resulted in approximately 50 to 80% suppression of SPHK1 mRNA expression as determined by real-time PCR. Down-regulation of SPHK1 with small interfering RNA significantly reduced SPHK1 protein levels by Western blotting. Knock down of SPHK1 expression significantly decreased cell proliferation of all MFH cells. These results suggest that the expression of S1P receptors may play an important role for cell proliferation and may correlate with histologic grade in malignant bone and soft tissue tumors, and that SPHK1 may be one of essential molecules for cell proliferation in MFH cell lines.

Sphingosine-1-phosphate derived from PRP-Exos promotes angiogenesis in diabetic wound healing via the S1PR1/AKT/FN1 signalling pathway

Background:Sphingosine-1-phosphate(S1P),a key regulator of vascular homeostasis and angiogenesis,is enriched in exosomes derived from platelet-rich plasma(PRP-Exos).However,the potential role of PRP-Exos-S1P in diabetic wound healing remains unclear.In this study,we investigated the underlying mechanism of PRP-Exos-S1P in diabetic angiogenesis and wound repair.Methods:Exosomes were isolated from PRP by ultracentrifugation and analysed by transmission electron microscopy,nanoparticle tracking analysis and western blotting.The concentration of S1P derived from PRP-Exos was measured by enzyme-linked immunosorbent assay.The expression level of S1P receptor1–3(S1PR1–3)in diabetic skin was analysed by Q-PCR.Bioinformatics analysis and proteomic sequencing were conducted to explore the possible signalling pathway mediated by PRP-Exos-S1P.A diabetic mouse model was used to evaluate the effect of PRP-Exos on wound healing.Immunofluorescence for cluster of differentiation 31(CD31)was used to assess angiogenesis in a diabetic wound model.Results:In vitro,PRP-Exos significantly promoted cell proliferation,migration and tube formation.Furthermore,PRP-Exos accelerated the process of diabetic angiogenesis and wound closure in vivo.S1P derived from PRP-Exos was present at a high level,and S1PR1 expression was significantly elevated compared with S1PR2 and S1PR3 in the skin of diabetic patients and animals.However,cell migration and tube formation were not promoted by PRP-Exos-S1P in human umbilical vein endothelial cells treated with shS1PR1.In the diabetic mouse model,inhibition of S1PR1 expression at wounding sites decreased the formation of new blood vessels and delayed the process of wound closure.Bioinformatics analysis and proteomics indicated that fibronectin 1(FN1)was closely related to S1PR1 due to its colocalization in the endothelial cells of human skin.Further study supported that FN1 plays an important role in the PRP-Exos-S1Pmediated S1PR1/protein kinase B signalling pathway.Conclusions:PRP-Exos-S1P promotes angiogenesis in diabetic wound healing via the S1PR1/protein kinase B/FN1 signalling pathway.Our findings provide a preliminary theoretical foundation for the treatment of diabetic foot ulcers using PRP-Exos in the future.

Siponimod exerts neuroprotective effects on the retina and higher visual pathway through neuronal S1PR1 in experimental glaucoma

Sphingosine-1-phosphate receptor(S1PR)signaling regulates diverse pathophysiological processes in the central nervous system.The role of S1PR signaling in neurodegenerative conditions is still largely unidentified.Siponimod is a specific modulator of S1P1 and S1P5 receptors,an immunosuppressant drug for managing secondary progressive multiple sclerosis.We investigated its neuroprotective properties in vivo on the retina and the brain in an optic nerve injury model induced by a chronic increase in intraocular pressure or acute N-methyl-D-aspartate excitotoxicity.Neuronal-specific deletion of sphingosine-1-phosphate receptor(S1PR1)was carried out by expressing AAV-PHP.eB-Cre recombinase under Syn1 promoter in S1PR1mice to define the role of S1PR1 in neurons.Inner retinal electrophysiological responses,along with histological and immunofluorescence analysis of the retina and optic nerve tissues,indicated significant neuroprotective effects of siponimod when administered orally via diet in chronic and acute optic nerve injury models.Further,siponimod treatment showed significant protection against trans-neuronal degenerative changes in the higher visual center of the brain induced by optic nerve injury.Siponimod treatment also reduced microglial activation and reactive gliosis along the visual pathway.Our results showed that siponimod markedly upregulated neuroprotective Akt and Erk1/2 activation in the retina and the brain.Neuronal-specific deletion of S1PR1 enhanced retinal and dorsolateral geniculate nucleus degenerative changes in a chronic optic nerve injury condition and attenuated protective effects of siponimod.In summary,our data demonstrated that S1PR1signaling plays a vital role in the retinal ganglion cell and dorsolateral geniculate nucleus neuronal survival in experimental glaucoma,and siponimod exerts direct neuroprotective effects through S1PR1 in neurons in the central nervous system independent of its peripheral immuno-modulatory effects.Our findings suggest that neuronal S1PR1 is a neuroprotective therapeutic target and its modulation by siponimod has positive implications in glaucoma conditions.

Approach to loss of response to advanced therapies in inflammatory bowel disease

BACKGROUND Remarkable progress over the last decade has equipped clinicians with many options in the treatment of inflammatory bowel disease.Clinicians now have the unique opportunity to provide individualized treatment that can achieve and sustain remission in many patients.However,issues of primary non-response(PNR)and secondary loss of response(SLOR)to non-tumour necrosis factor inhibitor(TNFi)therapies remains a common problem.Specific issues include the choice of optimization of therapy,identifying when dose optimization will recapture response,establishing optimal dose for escalation and when to switch therapy.AIM To explores the issues of PNR and SLOR to non-TNFi therapies.METHODS This review explores the current evidence and literature to elucidate management options in cases of PNR/SLOR.It will also explore potential predictors for response following SLOR/PNR to therapies including the role of therapeutic drug monitoring(TDM).RESULTS In the setting of PNR and loss of response to alpha-beta7-integrin inhibitors and interleukin(IL)-12 and IL-23 inhibitors dose optimization is a reasonable option to capture response.For Janus kinase inhibitors dose optimization can be utilized to recapture response with loss of response.CONCLUSION The role of TDM in the setting of advanced non-TNFi therapies to identify patients who require dose optimization and as a predictor for clinical remission is not yet established and this remains an area that should be addressed in the future.

To stay or to leave: Stem cells and progenitor cells navigating the S1P gradient

Most hematopoietic stem progenitor cells (HSPCs) reside in bone marrow (BM), but a small amount of HSPCs have been found to circulate between BM and tissues through blood and lymph. Several lines of evidence suggest that sphingosine-1-phosphate (S1P) gradient triggers HSPC egression to blood circulation after mobilization from BM stem cell niches. Stem cells also visit certain tissues. After a temporary 36 h short stay in local tissues, HSPCs go to lymph in response to S1P gradient between lymph and tissue and eventually enter the blood circulation. S1P also has a role in the guidance of the primitive HSPCs homing to BM in vivo, as S1P analogue FTY720 treatment can improve HSPC BM homing and engraftment. In stress conditions, various stem cells or progenitor cells can be attracted to local injured tissues and participate in local tissue cell differentiation and tissue rebuilding through modulation the expression level of S1P1, S1P2 or S1P3 receptors. Hence, S1P is important for stem cells circulation in blood system to accomplish its role in body surveillance and injury recovery.

Targeting sphingosine-1-phosphate signaling for cancer therapy

Sphingosine-1-phosphate(S1P) is a potent pleotropic bioactive lipid mediator involved in immune cell trafficking, cell survival,cell proliferation, cell migration, angiogenesis and many other cellular processes. S1 P either activates S1 P receptors(S1PR1-5) through "inside-out signaling" or acts directly on intracellular targets to regulate various cellular processes. In the past two decades, much progress has been made in exploring S1 P signaling and its pathogenic roles in diseases as well as in developing modulators of S1 P signaling, including S1 P agonists, S1 P antagonists and sphingosine kinase(SphK) inhibitors.Ceramide and S1 P have been defined as reciprocal regulators of cell fate, and S1 P signaling has been shown to be crucial for the pathogenesis of various diseases, including autoimmune diseases, inflammation and cancer; therefore, targeting S1 P signaling may curtail the process of pathogenesis and serve as a potential therapeutic target for the treatment of these diseases. In this review, we describe recent advances in our understanding of S1 P signaling in cancer development(particularly in inflammationassociated cancer) as well as in innate and adaptive immunity, and we also discuss modulators of S1 P signaling in cancer treatment.

Aryl hydrocarbon receptor signaling promotes ORMDL3- dependent generation of sphingosine-1-phosphate by inhibiting sphingosine-1-phosphate lyase

Aryl hydrocarbon receptor(AhR),a cellular chemical sensor,controls cellular homeostasis,and sphingosine-1-phosphate(S1P),a bioactive intermediate of sphingolipid metabolism,is believed to have a role in immunity and inflammation,but their potential crosstalk is currently unknown.We aimed to determine whether there is a functional linkage between AhR signaling and sphingolipid metabolism.We showed that AhR ligands,including an environmental polycyclic aromatic hydrocarbon(PAH),induced S1P generation,and inhibited S1P lyase(S1PL)activity in resting cells,antigen/IgE-activated mast cells,and mouse lungs exposed to the AhR ligand alone or in combination with antigen challenge.The reduction of S1PL activity was due to AhR-mediated oxidation of S1PL at residue 317,which was reversible by the addition of an antioxidant or in cells with knockdown of the ORMDL3 gene encoding an ER transmembrane protein,whereas C317A S1PL mutant-transfected cells were resistant to the AhR-mediated effect.Furthermore,analysis of AhR ligand-treated cells showed a time-dependent increase of the ORMDL3–S1PL complex,which was confirmed by FRET analysis.This change increased the S1P levels,which in turn,induced mast cell degranulation via S1PR2 signaling.In addition,elevated levels of plasma S1P were found in children with asthma compared to non-asthmatic subjects.These results suggest a new regulatory pathway whereby the AhR–ligand axis induces ORMDL3-dependent S1P generation by inhibiting S1PL,which may contribute to the expression of allergic diseases.

The sphingosine-1-phosphate/RhoA/Rho associated kinases/myosin light chain pathway in detrusor of female rats is down-regulated in response to ovariectomy

Background:Dysuria is one of the main symptoms of genitourinary syndrome of menopause,which causes serious disruption to the normal life of peri-menopausal women.Studies have shown that it is related to decrease of detrusor contractile function,but the exact mechanism is still poorly understood.Previous results have suggested that the sphingosine-1-phosphate(S1P)pathway can regulate detrusor contraction,and this pathway is affected by estrogen in various tissues.However,how estrogen affects this pathway in the detrusor has not been investigated.In this study,we detected changes of the S1P/RhoA/Rho associated kinases(ROCK)/myosin light chain(MLC)pathway in the detrusor of ovariectomized rats in order to explore the underlying mechanism of dysuria during peri-menopause.Methods::Thirty-six female Sprague-Dawley rats were randomly divided into SHAM(sham operation),OVX(ovariectomy),and E groups(ovariectomy+estrogen),with 12 rats in each group.We obtained bladder detrusor tissues from each group and examined the mRNA and protein levels of the major components of the S1P/RhoA/ROCK/MLC pathway using quantitative real-time polymerase chain reaction and Western blotting,respectively.We also quantified the content of S1P in the detrusor using an enzyme linked immunosorbent assay.Finally,we compared results between the groups with one-way analysis of variance.Results::The components of the S1P pathway and the RhoA/ROCK/MLC pathway of the OVX group were significantly decreased,as compared with SHAM group.The percent decreases of the components in the S1P pathway were as follows:sphingosine kinase 1(mRNA:39%,protein:45%)(both P<0.05),S1P(21.73±1.09 nmol/g vs.18.86±0.69 nmol/g)(P<0.05),and S1P receptor 2/3(S1PR2/3)(mRNA:25%,27%,respectively)(P<0.05).However,the protein expression levels of S1PR2/3 and the protein and mRNA levels of SphK2 and S1PR1 did not show significant differences between groups(P>0.05).The percent decreases of the components in the RhoA/ROCK/MLC pathway were as follows:ROCK2(protein:41%,mRNA:36%)(both P<0.05),p-MYPT1(protein:54%)(P<0.05),and p-MLC20(protein:47%)(P<0.05),but there were no significant differences in the mRNA and protein levels of RhoA,ROCK1,MYPT1,and MLC20(all P>0.05).In addition,all of the above-mentioned decreases could be reversed after estrogen supplementation(E group vs.SHAM group)(all P>0.05).Conclusion::In this study,we confirmed that ovariectomy is closely associated with the down-regulation of the S1P/RhoA/ROCK/MLC pathway in the rat detrusor,which may be one mechanism of dysuria caused by decreased contractile function of the female detrusor during peri-menopause.

Sphingosine-1-phosphate signaling and the gut-liver axis in liver diseases

The liver is the central organ involved in lipid metabolism and the gastrointestinal(GI)tract is responsible for nutrient absorption and partitioning.Obesity,dyslipidemia and metabolic disorders are of increasing public health concern worldwide,and novel therapeutics that target both the liver and the GI tract(gut-liver axis)are much needed.In addition to aiding fat digestion,bile acids act as important signaling molecules that regulate lipid,glucose and energy metabolism via activating nuclear receptor,G protein-coupled receptors(GPCRs),Takeda G protein receptor 5(TGR5)and sphingosine-1-phosphate receptor 2(S1PR2).Sphingosine-1-phosphate(S1P)is synthesized by two sphingosine kinase isoforms and is a potent signaling molecule that plays a critical role in various diseases such as fatty liver,in-flammatory bowel disease(IBD)and colorectal cancer.In this review,we will focus on recent findings related to the role of S1P-mediated signaling pathways in the gut-liver axis.

The predictive value of serum S1P and STIM1 levels after PCI for in-stent restenosis and their correlation with angiogenesis and inflammatory response

Objective:To study the predictive value of serum S1P and STIM1 levels after percutaneous coronary intervention (PCI) for in-stent restenosis and their correlation with angiogenesis and inflammatory response.Methods:130 patients who received PCI in our hospital between June 2013 and December 2016 were selected and divided into restenosis group and non-restenosis group according to the coronary angiography results 6-24 months after PCI. The serum levels of S1P, STIM1, angiogenesis molecules and inflammation molecules were detected 24 hours after PCI.Results:Serum S1P, NO, VEGF, Angptl2 and Angptl4 levels of restenosis group were significantly lower than those of non-restenosis group while STIM1, IFN-γ, IL-18, VCAM-1, P-selectin and L-selectin levels were significantly higher than those of non-restenosis group;serum NO, VEGF, Angptl2 and Angptl4 levels of restenosis group with lower STIM1 were significantly higher those of restenosis group with normal STIM1;serum IFN-γ, IL-18, VCAM-1, P-selectin and L-selectin levels of restenosis group with lower S1P were significantly higher than those of restenosis group with normal S1P.Conclusion:The decreased serum S1P and increased STIM1 after PCI have prediction value for in-stent restenosis and are closely related to the angiogenesis disorder and inflammation activation.

Fingolimod protects against neurovascular unit injury in a rat model of focal cerebral ischemia/reperfusion injury

Recent research on the underlying mechanisms of cerebral ischemia indicates that the neurovascular unit can be used as a novel subject for general surveys of neuronal damage and protein mechanisms.Fingolimod(FTY-720)is a newly developed immunosuppressant isolated from Cordyceps sinensis that exhibits a wide range of biological activities,and has recently attracted much attention for the treatment of ischemic cerebrovascular diseases.In the current research,the role of FTY-720 and its possible mechanisms were assessed from an neurovascular unit perspective using a rat cerebral ischemia model.Our results revealed that FTY-720 markedly decreased infarct volume,promoted neurological function recovery,and weakened the blood-brain barrier permeability of ischemic rats.The protective roles of FTY-720 in ischemic stroke are ascribed to a combination of sphingosin-1-phosphate receptor-1 and reduced expression of sphingosin-1-phosphate receptor-1 in microvessels and reduction of interleukin-17A protein levels.These findings indicate that FTY-720 has promise as a new therapy for neurovascular protection and functional recovery after ischemic stroke.

Advances in the management of peritoneal mesothelioma

Malignant peritoneal mesothelioma(PM) is an infrequent disease which has historically been associated with a poor prognosis. Given its long latency period and non-specific symptomatology, a diagnosis of PM can be suggested by occupational exposure history, but ultimately relies heavily on imaging and diagnostic biopsy. Early treatment options including palliative operative debulking, intraperitoneal chemotherapy, and systemic chemotherapy have marginally improved the natural course of the disease with median survival being approximately one year. The advent of cytoreduction(CRS) with hyperthermic intraperitoneal chemotherapy(HIPEC) has dramatically improved survival outcomes with wide median survival estimates between 2.5 to 9 years; these studies however remain largely heterogeneous, with differing study populations, tumor biology, and specific treatment regimens. More recent investigations have explored extent of cytoreduction, repeated operative intervention, and choice of chemotherapy but have been unable to offer definitive conclusions. CRS and HIPEC remain morbid procedures with complication rates ranging between 30% to 46% in larger series. Ac-cordingly, an increasing interest in identifying molecular targets and developing targeted therapies is emerging. Among such novel targets is sphingosine kinase 1(SphK1) which regulates the production of sphingosine-1-phosphate, a biologically active lipid implicated in various cancers including malignant mesothelioma. The known action of specific SphK inhibitors may warrant further exploration in peritoneal disease.

S1PR1 serves as a viable drug target against pulmonary fibrosis by increasing the integrity of the endothelial barrier of the lung

Idiopathic pulmonary fibrosis(IPF)is a progressive lung disease with unclear etiology and limited treatment options.The median survival time for IPF patients is approximately 2–3 years and there is no effective intervention to treat IPF other than lung transplantation.As important components of lung tissue,endothelial cells(ECs)are associated with pulmonary diseases.However,the role of endothelial dysfunction in pulmonary fibrosis(PF)is incompletely understood.Sphingosine-1-phosphate receptor 1(S1PR1)is a G protein-coupled receptor highly expressed in lung ECs.Its expression is markedly reduced in patients with IPF.Herein,we generated an endothelial-conditional S1pr1 knockout mouse model which exhibited inflammation and fibrosis with or without bleomycin(BLM)challenge.Selective activation of S1PR1 with an S1PR1 agonist,IMMH002,exerted a potent therapeutic effect in mice with bleomycin-induced fibrosis by protecting the integrity of the endothelial barrier.These results suggest that S1PR1 might be a promising drug target for IPF therapy.