Deficiency of the sphingosine-1-phosphate (S1P) transporter Mfsd2b protects the heart against hypertension-induced cardiac remodeling by suppressing the L-type-Ca2+ channel.

The erythrocyte S1P transporter Mfsd2b is also expressed in the heart. We hypothesized that S1P transport by Mfsd2b is involved in cardiac function. Hypertension-induced cardiac remodeling was induced by 4-weeks Angiotensin II (AngII) administration and assessed by echocardiography. Ca2+ transients and sarcomere shortening were examined in adult cardiomyocytes (ACM) from Mfsd2b+/+ and Mfsd2b-/- mice. Tension and force development were measured in skinned cardiac fibers. Myocardial gene expression was determined by real-time PCR, Protein Phosphatase 2A (PP2A) by enzymatic assay, and S1P by LC/MS, respectively. Msfd2b was expressed in the murine and human heart, and its deficiency led to higher cardiac S1P. Mfsd2b-/- mice had regular basal cardiac function but were protected against AngII-induced deterioration of left-ventricular function as evidenced by ~ 30% better stroke volume and cardiac index, and preserved ejection fraction despite similar increases in blood pressure. Mfsd2b-/- ACM exhibited attenuated Ca2+ mobilization in response to isoprenaline whereas contractility was unchanged. Mfsd2b-/- ACM showed no changes in proteins responsible for Ca2+ homeostasis, and skinned cardiac fibers exhibited reduced passive tension generation with preserved contractility. Verapamil abolished the differences in Ca2+ mobilization between Mfsd2b+/+ and Mfsd2b-/- ACM suggesting that S1P inhibits L-type-Ca2+ channels (LTCC). In agreement, intracellular S1P activated the inhibitory LTCC phosphatase PP2A in ACM and PP2A activity was increased in Mfsd2b-/- hearts. We suggest that myocardial S1P protects from hypertension-induced left-ventricular remodeling by inhibiting LTCC through PP2A activation. Pharmacologic inhibition of Mfsd2b may thus offer a novel approach to heart failure.

[Small Molecule Therapy for Inflammatory Bowel Disease: JAK Inhibitors and S1PR Modulators].

Small molecules, including Janus kinase (JAK) inhibitors and sphingosine-1-phosphate receptor modulators (S1PRMs), are promising new treatments for inflammatory bowel disease (IBD). Small molecules exhibit more predictable pharmacokinetics than biologics, are less likely to induce immune responses, and can be administered orally. JAK inhibitors function by blocking the activity of JAK enzymes, which prevents the subsequent phosphorylation and activation of signal transducer and activator of transcription (STAT) proteins. Tofacitinib and filgotinib are approved for treating ulcerative colitis (UC), while upadacitinib is approved for UC and Crohn's disease. Nevertheless, JAK inhibitors can increase the risk of herpes zoster, cancer, major adverse cardiovascular events, and venous thromboembolism. S1PRMs bind to S1PRs, particularly S1PR1, on lymphocytes. This interaction inhibits lymphocytes from exiting the lymph nodes and migrating to the gut, thereby reducing inflammation and the immune response in the intestinal mucosa. Ozanimod and etrasimod are S1PRMs approved for the treatment of UC, but they can cause side effects such as bradycardia, conduction disorder, and macular edema. Overall, JAK inhibitors and S1PRMs offer significant benefits in managing IBD, although their potential side effects require careful monitoring.

Sphingosine-1-Phosphate Receptor 4 links neutrophils and early local inflammation to lymphocyte recruitment into the draining lymph node to facilitate robust germinal center formation.

The successful development of germinal centers (GC) relies heavily on innate mechanisms to amplify the initial inflammatory cascade. In addition to their role in antigen presentation, innate cells are essential for the redirection of circulating lymphocytes toward the draining lymph node (dLN) to maximize antigen surveillance. Sphingosine-1-Phosphate (S1P) and its receptors (S1PR1-5) affect various aspects of immunity; however, the role of S1PR4 in regulating an immune response is not well understood. Here we use a footpad model of localized TH1 inflammation to carefully monitor changes in leukocyte populations within the blood, the immunized tissue, and the dLN. Within hours of immunization, neutrophils failed to adequately mobilize and infiltrate into the footpad tissue of S1PR4-/- mice, thereby diminishing the local vascular changes thought to be necessary for redirecting circulating cells toward the inflamed region. Neutrophil depletion with anti-Ly6G antibodies significantly reduced early tissue edema as well as the redirection and initial accumulation of naïve lymphocytes in dLN of WT mice, while the effects were less prominent or absent in S1PR4-/- dLN. Adoptive transfer experiments further demonstrated that the lymphocyte homing deficiencies in vivo were not intrinsic to the donor S1PR4-/- lymphocytes, but were instead attributed to differences within the S1PR4-deficient host. Reduced cell recruitment in S1PR4-/- mice would seed the dLN with fewer antigen-respondent lymphocytes and indeed, dLN hypertrophy at the peak of the immune response was severely diminished, with attenuated GC and activation pathways in these mice. Histological examination of the S1PR4-/- dLN also revealed an underdeveloped vascular network with reduced expression of the leukocyte tethering ligand, PNAd, within high endothelial venule regions, suggesting inadequate growth of the dLN meant to support a robust GC response. Thus, our study reveals that S1PR4 may link early immune modulation by neutrophils to the initial recruitment of circulating lymphocytes and downstream expansion and maturation of the dLN, thereby contributing to optimal GC development during an adaptive response.

Sphingosine 1-Phosphate Stimulates ER to Golgi Ceramide Traffic to Promote Survival in T98G Glioma Cells.

Glioblastoma multiforme is the most common and fatal brain tumor among human cancers. Ceramide (Cer) and Sphingosine 1-phosphate (S1P) have emerged as bioeffector molecules that control several biological processes involved in both cancer development and resistance. Cer acts as a tumor suppressor, inhibiting cancer progression, promoting apoptosis, enhancing immunotherapy and sensitizing cells to chemotherapy. In contrast, S1P functions as an onco-promoter molecule, increasing proliferation, survival, invasiveness, and resistance to drug-induced apoptosis. The pro-survival PI3K/Akt pathway is a recognized downstream target of S1P, and we have previously demonstrated that in glioma cells it also improves Cer transport and metabolism towards complex sphingolipids in glioma cells. Here, we first examined the possibility that, in T98G glioma cells, S1P may regulate Cer metabolism through PI3K/Akt signaling. Our research showed that exogenous S1P increases the rate of vesicular trafficking of Cer from the endoplasmic reticulum (ER) to the Golgi apparatus through S1P receptor-mediated activation of the PI3K/Akt pathway. Interestingly, the effect of S1P results in cell protection against toxicity arising from Cer accumulation in the ER, highlighting the role of S1P as a survival factor to escape from the Cer-generating cell death response.

FTY720/Fingolimod mitigates paclitaxel-induced Sparcl1-driven neuropathic pain and breast cancer progression.

Paclitaxel is among the most active chemotherapy drugs for the aggressive triple negative breast cancer (TNBC). Unfortunately, it often induces painful peripheral neuropathy (CIPN), a major debilitating side effect. Here we demonstrate that in naive and breast tumor-bearing immunocompetent mice, a clinically relevant dose of FTY720/Fingolimod that targets sphingosine-1-phosphate receptor 1 (S1PR1), alleviated paclitaxel-induced neuropathic pain. FTY720 also significantly attenuated paclitaxel-stimulated glial fibrillary acidic protein (GFAP), a marker for activated astrocytes, and expression of the astrocyte-secreted synaptogenic protein Sparcl1/Hevin, a key regulator of synapse formation. Notably, the formation of excitatory synapses containing VGluT2 in the spinal cord dorsal horn induced by paclitaxel was also inhibited by FTY720 treatment, supporting the involvement of astrocytes and Sparcl1 in CIPN. Furthermore, in this TNBC mouse model that mimics human breast cancer, FTY720 administration also enhanced the anti-tumor effects of paclitaxel, leading to reduced tumor progression and lung metastasis. Taken together, our findings suggest that targeting the S1P/S1PR1 axis with FTY720 is a multipronged approach that holds promise as a therapeutic strategy for alleviating both CIPN and enhancing the efficacy of chemotherapy in TNBC treatment.

Multiple-dose pharmacokinetics of cenerimod and the effect of charcoal on its elimination.

Cenerimod is a sphingosine-1-phosphate receptor 1 modulator that reduces tissue availability of circulating lymphocytes. The compound is in Phase 3 development for the treatment of systemic lupus erythematosus. Its pharmacokinetic properties are characterized by slow absorption and multiphasic elimination with a long terminal half-life (t½), potentially caused by enterohepatic circulation (EHC). In this trial in healthy participants, oral cenerimod 0.5 and 4 mg once daily was administered for 50 days, followed by oral administration of activated charcoal (ie, 50 mg every 12 h for 11 days, starting 24 h after the last cenerimod dose), to investigate the potential EHC of cenerimod and assess whether elimination of cenerimod can be accelerated. The multiple-dose pharmacokinetics, pharmacodynamics, safety, and tolerability of cenerimod were also evaluated. For both doses, peak plasma concentrations were reached 6 and 7 h after dosing. Cenerimod accumulated approximately eightfold and (near) steady-state conditions were reached after 50 doses, resembling clinically meaningful exposure to cenerimod. The t½ following 0.5 and 4 mg of cenerimod was 767 and 799 h (ie, 32 and 33 days) and 720 and 780 h (ie, 30 and 33 days) with or without administration of charcoal, respectively, indicating no statistically significant difference. Therefore, charcoal did not accelerate cenerimod elimination suggesting that there is no EHC of cenerimod. A reversible, dose-dependent decrease in total lymphocyte count was observed. No safety concerns were identified; administration of charcoal was well tolerated.

Sphingosine 1-phosphate protective effect on human proximal tubule cells submitted to an in vitro ischemia model: the role of JAK2/STAT3.

Acute kidney injury is a serious public health problem worldwide, being ischemia and reperfusion (I/R) the main lesion-aggravating factor that contributes to the evolution towards chronic kidney disease. Nonetheless, intervention approaches currently available are just considered palliative options. In order to offer an alternative treatment, it is important to understand key factors involved in the development of the disease including the rescue of the affected cells and/or the release of paracrine factors that are crucial for tissue repair. Bioactive lipids such as sphingosine 1-phosphate (S1P) have significant effects on the modulation of signaling pathways involved in tissue regeneration, such as cell survival, proliferation, differentiation, and migration. The main objective of this work was to explore the protective effect of S1P using human kidney proximal tubule cells submitted to a mimetic I/R lesion, via ATP depletion. We observed that the S1P pre-treatment increases cell survival by 50% and preserves the cell proliferation capacity of injured cells. We showed the presence of different bioactive lipids notably related to tissue repair but, more importantly, we noted that the pre-treatment with S1P attenuated the ischemia-induced effects in response to the injury, resulting in higher endogenous S1P production. All receptors but S1PR3 are present in these cells and the protective and proliferative effect of S1P/S1P receptors axis occur, at least in part, through the activation of the SAFE pathway. To our knowledge, this is the first time that S1PR4 and S1PR5 are referred in these cells and also the first indication of JAK2/STAT3 pathway involvement in S1P-mediated protection in an I/R renal model.

Functional Insights into the Sphingolipids C1P, S1P, and SPC in Human Fibroblast-like Synoviocytes by Proteomic Analysis.

The (patho)physiological function of the sphingolipids ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P), and sphingosylphosphorylcholine (SPC) in articular joints during osteoarthritis (OA) is largely unknown. Therefore, we investigated the influence of these lipids on protein expression by fibroblast-like synoviocytes (FLSs) from OA knees. Cultured human FLSs (n = 7) were treated with 1 of 3 lipid species-C1P, S1P, or SPC-IL-1ß, or with vehicle. The expression of individual proteins was determined by tandem mass tag peptide labeling followed by high-resolution electrospray ionization (ESI) mass spectrometry after liquid chromatographic separation (LC-MS/MS/MS). The mRNA levels of selected proteins were analyzed using RT-PCR. The 3sphingolipids were quantified in the SF of 18 OA patients using LC-MS/MS. A total of 4930 proteins were determined using multiplex MS, of which 136, 9, 1, and 0 were regulated both reproducibly and significantly by IL-1ß, C1P, S1P, and SPC, respectively. In the presence of IL-1ß, all 3 sphingolipids exerted ancillary effects. Only low SF levels of C1P and SPC were found. In conclusion, the 3 lipid species regulated proteins that have not been described in OA. Our results indicate that charged multivesicular body protein 1b, metal cation symporter ZIP14, glutamine-fructose-6-P transaminase, metallothionein-1F and -2A, ferritin, and prosaposin are particularly interesting proteins due to their potential to affect inflammatory, anabolic, catabolic, and apoptotic mechanisms.

Syndecan-1 as a predictor of vulnerable atherosclerotic plaques.

Aims: Cardiovascular disease remains a major global health concern, with atherosclerosis (AS) being a significant contributor. Vulnerable plaques play a critical role in acute cardiovascular events. Syndecan-1 (SDC-1), a vital membrane proteoglycan in the vascular endothelial glycocalyx, is believed to be associated with plaque progression. However, its precise relationship with severity and vulnerability of atherosclerotic plaque remains unclear. This study aimed to investigate SDC-1 expression and its potential correlation with plaque vulnerability in ApoE-/- atherosclerosis mouse model. Methods and results: Eight-week-old mice were induced into the AS model using a high-fat diet (HFD) and/or partial ligation of the left common carotid artery (PLCA), with a chow diet (CD) control group. After 16 weeks, plaques in the aortic root showed the following order: HFD + PLCA group > HFD group > CD + PLCA group > CD group. Immunohistochemistry revealed heightened accumulation of lipid/foam cells and CD68-labeled macrophages in the plaques, elevated vascular endothelial growth factor (VEGF), and matrix Metalloproteinase-9 (MMP-9) in the HFD + PLCA group's plaques, along with reduced collagen and α-SMA-labeled smooth muscle cells, resulting in the highest vulnerability index value. Immunohistofluorescence analysis of frozen plaque sections showed significantly higher SDC-1 expression in the AS mice group compared to the CD group, both positively correlated with plaque vulnerability. Serum analysis demonstrated elevated levels of SDC1, sphingosine 1-phosphate (S1P), and VEGF-A in the AS mice, all positively correlated with plaque vulnerability. Multivariate analysis identified SDC1 as an independent predictor of plaque vulnerability. Conclusion: This study enhances our understanding of plaque vulnerability mechanisms and presents SDC1 as a potential biomarker for atherosclerosis. These findings underscore the importance of addressing modifiable risk factors, such as diet and hemodynamics and suggest the utility of serum SDC1 as a valuable clinical marker. Ultimately, these insights may lead to more effective strategies in combating cardiovascular diseases and improving patient outcomes.

Knockdown of nicotinamide N-methyltransferase ameliorates renal fibrosis caused by ischemia-reperfusion injury and remodels sphingosine metabolism.

BACKGROUND: CKD currently affects 8.2% to 9.1% of the global population and the CKD mortality rate has increased during recent decades, making it necessary to identify new therapeutic targets. This study investigated the role of nicotinamide N-methyltransferase (NNMT) in renal fibrosis following ischemia-reperfusion injury (IRI), a key factor in chronic kidney disease (CKD) progression. METHODS: We established a mouse model with a knockdown of NNMT to investigate the impact of this enzyme on renal fibrosis after unilateral IRI. We then utilized histology, immunohistochemistry, and metabolomic analyses to investigate fibrosis markers and sphingolipid metabolism in NNMT-deficient mice. We also utilized an Nnmt lentivirus interference vector or an Nnmt overexpression plasmid to transfect mouse kidney proximal tubule cells, stimulated these cells with TGF-ß1, and then measured the pro-fibrotic response and the expression of the methylated and unmethylated forms of Sphk1. RESULTS: The results demonstrated that reducing NNMT expression mitigated fibrosis, inflammation, and lipid deposition, potentially through the modulation of sphingolipid metabolism. Histology, immunohistochemistry, and metabolomic analyses provided evidence of decreased fibrosis and enhanced sphingolipid metabolism in NNMT-deficient mice. NNMT mediated the TGF-ß1-induced pro-fibrotic response, knockdown of Nnmt decreased the level of unmethylated Sphk1 and increased the level of methylated Sphk1 in renal tubular epithelial cells. CONCLUSIONS: Our findings suggest that NNMT functions in sphingolipid metabolism and has potential as a therapeutic target for CKD. Further research is needed to elucidate the mechanisms linking NNMT to sphingolipid metabolism and renal fibrosis.

Injectable multifunctional hydrogel containing Sphingosine 1-phosphate and human acellular amniotic membrane for skin wound healing.

Objectives: The skin serves as the main defense barrier, protecting against injuries, and preventing infection and water loss. Consequently, wound healing and skin regeneration are crucial aspects of wound management. A novel hydrogel scaffold was developed by incorporating carboxymethyl cellulose (CMC) and gelatin (Gel) hydrogels cross-linked with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) containing Sphingosine 1-phosphate (S1P). This hydrogel is applied topically to treat acute wounds and is covered with a human acellular amniotic membrane (hAAM) as a secondary dressing. Materials and Methods: The scaffold was subjected to in vitro cell viability, red blood cell hemolysis, blood clotting index, and in vivo assays. Real-time PCR was implemented to verify the expression of genes involved in skin wounds. The physical and chemical properties of the scaffolds were also tested using weight loss, swelling ratio, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and mechanical tensile analysis. Results: The synthetic scaffold is biocompatible as evidenced by the high percentage of 3T3 cell viability (127%) after 72 hr. Additionally, excellent hemocompatibility with a low hemolytic effect (2.26%) was observed. Our in vivo wound healing assay demonstrated that CMC/Gel/S1P/hAAM wound dressing led to faster wound healing in treated rats compared to the control group over 14.Also, the mechanical tests showed that the amniotic membrane and the hAAM had very different Young's modulus and elongation at break values. Conclusion: This study demonstrates the effectiveness of the CMC/Gel/EDC hydrogel with S1P as a wound dressing. Additionally, hAAM exhibits excellent characteristics as a protective layer for the treatment of acute wounds.

Inhibition of Sphingosine Kinase 1 Reduces Sphingosine-1-Phosphate and Exacerbates Amyloid-Beta-Induced Neuronal Cell Death in Mixed-Glial-Cell Culture.

In Alzheimer's disease (AD) pathology, the accumulation of amyloid-beta (Aß), a main component of senile plaques, activates glial cells and causes neuroinflammation. Excessive neuroinflammation results in neuronal dropouts and finally produces the symptoms of AD. Recent studies suggest that disorder in sphingosine-1-phosphate (S1P) metabolism, especially the decreased expression of sphingosine kinase (SK)1, followed by the reduction in the amount of S1P, can be a promotive factor in AD onset. Thus, we explored the possibility that dysregulated S1P metabolism affects AD through the altered function in glial cells. We evaluated the effect of PF-543, a pharmacological inhibitor of SK1, on the inflammatory responses by lipopolysaccharide (LPS)-activated glial cells, microglia, and astrocytes. The treatment with PF-543 decreased the intracellular S1P content in glial cells. The PF-543 treatment enhanced the nitric oxide (NO) production in the LPS-treated neuron/glia mixed culture. Furthermore, we found that the augmented production of NO and reactive oxygen species (ROS) in the PF-543-treated astrocytes affected the microglial inflammatory responses through humoral factors in the experiment using an astrocyte-conditioned medium. The PF-543 treatment also decreased the microglial Aß uptake and increased the number of injured neurons in the Aß-treated neuron/glia mixed culture. These results suggest that a decrease in the glial S1P content can exacerbate neuroinflammation and neurodegeneration through altered glial cell functions.

[Translated article] Risk of Skin Cancer Associated with Disease-Modifying Therapies in Multiple Sclerosis: A Comprehensive Evidence Review.

The use of disease-modifying therapies (DMT) has led to a paradigm shift in the management of multiple sclerosis. A comprehensive narrative review was conducted through an extensive literature search including Medline and Google Scholar to elucidate the link between DMT and the propensity of cutaneous malignancies. Sphingosine-1-phosphate receptor modulators, such as fingolimod and siponimod are associated with a higher risk of basal cell carcinoma (BCC), but not squamous cell carcinoma, or melanoma. The associated physiopathological mechanisms are not fully understood. Alemtuzumab and cladribine show isolated associations with skin cancer. Regarding other DMT, no increased risk has ever been found. Given the evidence currently available, it is of paramount importance to advocate for necessary dermatological assessments that should be individualized to the risk profile of each patient. Nonetheless, additional prospective studies are still needed to establish efficient dermatological follow-up protocols.

The fate of intracellular S1P regulates lipid droplet turnover and lipotoxicity in pancreatic beta-cells.

Lipotoxicity has been considered the main cause of pancreatic beta-cell failure during type 2 diabetes development. Lipid droplets (LD) are believed to regulate the beta-cell sensitivity to free fatty acids (FFA), but the underlying molecular mechanisms are largely unclear. Accumulating evidence points, however, to an important role of intracellular sphingosine-1-phosphate (S1P) metabolism in lipotoxicity-mediated disturbances of beta-cell function. In the present study, we compared the effects of an increased irreversible S1P degradation (S1P-lyase, SPL overexpression) with those associated with an enhanced S1P recycling (overexpression of S1P phosphatase 1, SGPP1) on LD formation and lipotoxicity in rat INS1E beta-cells. Interestingly, although both approaches led to a reduced S1P concentration, they had opposite effects on the susceptibility to FFA. Overexpression of SGPP1 prevented FFA-mediated caspase-3 activation by a mechanism involving an enhanced lipid storage capacity and prevention of oxidative stress. In contrast, SPL overexpression limited LD biogenesis, content, and size, while accelerating lipophagy. This was associated with FFA-induced hydrogen peroxide formation, mitochondrial fragmentation, and dysfunction, as well as ER stress. These changes coincided with the upregulation of proapoptotic ceramides but were independent of lipid peroxidation rate. Also in human EndoC-ßH1 beta-cells, suppression of SPL with simultaneous overexpression of SGPP1 led to a similar and even more pronounced LD phenotype as that in INS1E-SGPP1 cells. Thus, intracellular S1P turnover significantly regulates LD content and size and influences beta-cell sensitivity to FFA.

Inhibiting sphingosine 1-phosphate lyase: From efficacy to mechanism.

Sphingosine-1 phosphate (S1P) is a lipid metabolite regulating diverse biological processes, including proliferation, differentiation, migration, and apoptosis, highlighting its physiological and therapeutic significance. Current S1P-based therapeutic approaches primarily focus on modulating the downstream signalling via targeting S1P receptors, however, this is challenged by incomplete receptor internalisation. Sphingosine-1-phosphate lyase (SPL) is a highly conserved enzyme that "gatekeeps" the final step of S1P degradation. Cognisant of the complex ligand and receptor interaction and dynamic metabolic networks, the selective modulation of SPL activity presents a new opportunity to regulate S1P biosynthesis and reveal its role in various systems. Over the past decade, an evolving effort has been made to identify new molecules that could block SPL activity in vitro or in vivo. This review focuses on summarising the current understanding of the reported SPL inhibitors identified through various screening approaches, discussing their efficacy in diverse model systems and the possible mechanism of action. Whilst effective modulation of S1P levels via inhibiting SPL is feasible, the specificity of those inhibitors remains inconclusive, presenting a clear challenge for future implications. Yet, none of the currently available SPL inhibitors is proven effective in elevating S1P levels within the central nervous system. This review article embraces future research focusing on investigating selective SPL inhibitors with high potency and possibly blood-brain-barrier permeability, which would aid the development of new S1P-based therapeutics for neurological disorders.

Icanbelimod (CBP-307), a next-generation Sphingosine-1-phosphate receptor modulator, in healthy men: pharmacokinetics, pharmacodynamics, safety, and tolerability in a randomized trial in Australia.

Background: Icanbelimod (formerly CBP-307) is a next-generation S1PR modulator, targeting S1PR1. In this first-in-human study, icanbelimod was investigated in healthy men in Australia. Methods: Participants were randomized 3:1, double-blind, to icanbelimod or placebo in four single-dose cohorts (0.1 mg, 0.25 mg, 0.5 mg [n=8 per cohort], 2.5 mg [n=4]) or for 28-days once-daily treatment in two cohorts (0.15 mg, 0.25 mg [n=8 per cohort]). Participants in the 0.25-mg cohort received 0.1 mg on Day 1. Treatments were administered orally after fasting; following one-week washout, icanbelimod was administered after breakfast in the 0.5-mg cohort. Results: Icanbelimod exposure increased rapidly and dose-dependently with single and multiple dosing (Tmax 4-7 hours). Lymphocyte counts decreased rapidly after single (-11%, 0.1 mg; -40%, 0.25 mg; -71%, 0.5 mg; -77%, 2.5 mg) and multiple doses (-49%, 0.15 mg; -75%, 0.25 mg), and recovered quickly, 7 days after dosing. After single-dose 0.5 mg, although a high-fat breakfast versus fasting did not affect maximal decrease, lymphocyte counts tended to be lower after breakfast across most timepoints up to 72 hours. Twenty-eight participants (63.6%) experienced mainly mild treatment-emergent adverse events (TEAEs). After single-dose icanbelimod, the most common TEAEs were headache (28.6%, n=6) and dizziness (19.0%, n=4). Three participants experienced transient bradycardia, with one serious, following single-dose 2.5 mg icanbelimod. After multiple-dose icanbelimod, the most common TEAEs were headache (50.0%, n=6) and lymphopenia (41.7%, n=5), and two participants withdrew due to non-serious TEAEs. Up-titration attenuated heart rate reductions. Conclusion: Icanbelimod was well-tolerated up to 0.5 mg and effectively reduced lymphocyte counts. Clinical trial registration: ClinicalTrials.gov, identifier NCT02280434.b.

Sphingosine-1-phosphate signalling in the heart: exploring emerging perspectives in cardiopathology.

Cardiometabolic disorders contribute to the global burden of cardiovascular diseases. Emerging sphingolipid metabolites like sphingosine-1-phosphate (S1P) and its receptors, S1PRs, present a dynamic signalling axis significantly impacting cardiac homeostasis. S1P's intricate mechanisms extend to its transportation in the bloodstream by two specific carriers: high-density lipoprotein particles and albumin. This intricate transport system ensures the accessibility of S1P to distant target tissues, influencing several physiological processes critical for cardiovascular health. This review delves into the diverse functions of S1P and S1PRs in both physiological and pathophysiological conditions of the heart. Emphasis is placed on their diverse roles in modulating cardiac health, spanning from cardiac contractility, angiogenesis, inflammation, atherosclerosis and myocardial infarction. The intricate interplays involving S1P and its receptors are analysed concerning different cardiac cell types, shedding light on their respective roles in different heart diseases. We also review the therapeutic applications of targeting S1P/S1PRs in cardiac diseases, considering existing drugs like Fingolimod, as well as the prospects and challenges in developing novel therapies that selectively modulate S1PRs.

Effect on neutrophil migration and antimicrobial functions by the Bruton's tyrosine kinase inhibitors tolebrutinib, evobrutinib and fenebrutinib.

Multiple sclerosis (MS) is a neurodegenerative, autoimmune disease that is still incurable. Nowadays, a variety of new drugs are being developed to prevent excessive inflammation and halt neurodegeneration. Among these are the inhibitors of Bruton's tyrosine kinase (BTK). Being indispensable for B cells, this enzyme became an appealing therapeutic target for autoimmune diseases. Recognizing the emerging importance of BTK in myeloid cells, we investigated the impact of upcoming BTK inhibitors on neutrophil functions. Although adaptive immunity in MS has been thoroughly studied, unanswered questions about the pathogenesis can be addressed by studying the effects of candidate MS drugs on innate immune cells such as neutrophils, previously overlooked in MS. In this study, we used three BTK inhibitors (evobrutinib, fenebrutinib and tolebrutinib), and found that they reduce neutrophil activation by the bacterial peptide N-formylmethionyl-leucyl-phenylalanine and the chemokine interleukin 8/CXCL8. Furthermore, they diminished the production of reactive oxygen species and release of neutrophil extracellular traps. Additionally, the production of CXCL8 and interleukin-1ß in response to inflammatory stimuli was decreased. Inhibitory effects of the drugs on neutrophil activation were not related to toxicity. Instead, BTK inhibitors prolonged neutrophil survival in an inflammatory environment. Finally, treatment with BTK inhibitors decreased neutrophil migration towards CXCL8 in a Boyden chamber assay but not in a trans endothelial set-up. Also, in vivo CXCL1-induced migration was unaffected by BTK inhibitors. Collectively, this study provides novel insights into the impact of BTK inhibitors on neutrophil functions, thereby holding important implications for autoimmune or hematological diseases where BTK is crucial.

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.

Analysis of Lipid GPCR Molecular Interactions by Proximity Labeling.

G-protein-coupled receptors (GPCRs) are hepta-helical transmembrane proteins that mediate various intracellular signaling events in response to their specific ligands including many lipid mediators. Although analyses of GPCR molecular interactions are pivotal to understanding diverse intracellular signaling events, affinity purification of interacting proteins by a conventional co-immunoprecipitation method is challenging due to the hydrophobic nature of GPCRs and their dynamic molecular interactions. Proximity labeling catalyzed by a TurboID system is a powerful technique for defining the molecular interactions of target proteins in living cells. TurboID and miniTurbo (a modified version of TurboID) are engineered biotin ligases that biotinylate neighboring proteins in a promiscuous manner. When fused with a target protein and expressed in living cells, TurboID or miniTurbo mediates the biotin labeling of the proteins with close proximity to the target protein, allowing efficient purification of the biotinylated proteins followed by a shot-gun proteomic analysis. In this chapter, we describe a step-by-step protocol for the labeling of GPCR neighboring proteins by TurboID or miniTurbo, purification of the biotin-labeled proteins, and subsequent sample preparation for proteomic analysis. We utilized S1PR1 as a model GPCR, a receptor for a bioactive lipid molecule sphingosine 1-phosphate (S1P) that plays various roles in physiological and pathological conditions. This analysis pipeline enables the mapping of interacting proteins of lipid GPCRs in living cells.