Fingolimod ameliorates acetic acid-induced ulcerative colitis: An insight into its modulatory impact on pro/anti-inflammatory cytokines and AKT/mTOR signalling

Therapeutic Potential of Fingolimod on Psychological Symptoms and Cognitive Function in Neuropsychiatric and Neurological Disorders

Neuropsychiatric and neurological disorders pose a significant global health burden, highlighting the need for innovative therapeutic approaches. Fingolimod (FTY720), a common drug to treat multiple sclerosis, has shown promising efficacy against various neuropsychiatric and neurological disorders. Fingolimod exerts its neuroprotective effects by targeting multiple cellular and molecular processes, such as apoptosis, oxidative stress, neuroinflammation, and autophagy. By modulating Sphingosine-1-Phosphate Receptor activity, a key regulator of immune cell trafficking and neuronal function, it also affects synaptic activity and strengthens memory formation. In the hippocampus, fingolimod decreases glutamate levels and increases GABA levels, suggesting a potential role in modulating synaptic transmission and neuronal excitability. Taken together, fingolimod has emerged as a promising neuroprotective agent for neuropsychiatric and neurological disorders. Its broad spectrum of cellular and molecular effects, including the modulation of apoptosis, oxidative stress, neuroinflammation, autophagy, and synaptic plasticity, provides a comprehensive therapeutic approach for these debilitating conditions. Further research is warranted to fully elucidate the mechanisms of action of fingolimod and optimize its use in the treatment of neuropsychiatric and neurological disorders.

Therapeutic Potential for Sphingolipids in Inflammatory Bowel Disease and Colorectal Cancer

Inflammatory bowel disease (IBD), characterized by chronic inflammation in the intestinal tract, increases the risk for the development of colorectal cancer (CRC). Sphingolipids, which have been implicated in IBD and CRC, are a class of bioactive lipids that regulate cell signaling, differentiation, apoptosis, inflammation, and survival. The balance between ceramide (Cer), the central sphingolipid involved in apoptosis and differentiation, and sphingosine-1-phosphate (S1P), a potent signaling molecule involved in proliferation and inflammation, is vital for the maintenance of normal cellular function. Altered sphingolipid metabolism has been implicated in IBD and CRC, with many studies highlighting the importance of S1P in inflammatory signaling and pro-survival pathways. A myriad of sphingolipid analogues, inhibitors, and modulators have been developed to target the sphingolipid metabolic pathway. In this review, the efficacy and therapeutic potential for modulation of sphingolipid metabolism in IBD and CRC will be discussed.

FTY720 attenuates acute colitis via colonic T cells reduction and inhibition of M1 macrophages polarization independent of CCR2-mediated monocytes input

Ulcerative colitis (UC) is a complex multifactorial disease, of which the exact etiology is not fully understood. The inappropriate aggressive inflammatory response is closely related to the disease progression of UC. FTY720 is a sphingosine-1-phosphate receptor agonist and acts as a key immunomodulator in inflammation. This study aims to investigate the protective influence of FTY720 on inflammation in the DSS-induced colitis model. In the present study, the C57BL/6 mice and the CCR2-/- mice were exposed to 5% Dextran Sodium Sulfate (DSS) drinking water for 6 days followed by an injection of FTY720 (1 mg/kg/d) or vehicle (PBS) 6 times starting on the next day. The body weight, stool consistency, and occult blood were assessed daily. The inflammatory cytokines level in colon tissues and serum were assessed. Leukocyte subsets of bone marrow (BM), spleen, and colon were analyzed by flow cytometry. Our results demonstrated that FTY720 ameliorated the aberrant immune responses by trapping T cells and inhibiting the polarization of M1 macrophages in colitis mice. The effect of FTY720 on the increased number of colonic macrophages did not dependent on CCR2-mediated monocyte influx, despite most monocytes being reduced after DSS administration in the inflamed colon of CCR2-/- mice. Rather, depletion of CCR2 did not impact the protective influence of FTY720 on colonic injury in acute colitis. All these findings unravel a beneficial function of FTY720 in the inflammatory response to DSS-induced acute colitis, provided further insights into monocyte migration and might provide potential opportunities for UC therapeutic intervention.

Implications of immunometabolism for smouldering MS pathology and therapy

Clinical symptom worsening in patients with multiple sclerosis (MS) is driven by inflammation compartmentalized within the CNS, which results in chronic neuronal damage owing to insufficient repair mechanisms. The term 'smouldering inflammation' summarizes the biological aspects underlying this chronic, non-relapsing and immune-mediated mechanism of disease progression. Smouldering inflammation is likely to be shaped and sustained by local factors in the CNS that account for the persistence of this inflammatory response and explain why current treatments for MS do not sufficiently target this process. Local factors that affect the metabolic properties of glial cells and neurons include cytokines, pH value, lactate levels and nutrient availability. This Review summarizes current knowledge of the local inflammatory microenvironment in smouldering inflammation and how it interacts with the metabolism of tissue-resident immune cells, thereby promoting inflammatory niches within the CNS. The discussion highlights environmental and lifestyle factors that are increasingly recognized as capable of altering immune cell metabolism and potentially responsible for smouldering pathology in the CNS. Currently approved MS therapies that target metabolic pathways are also discussed, along with their potential for preventing the processes that contribute to smouldering inflammation and thereby to progressive neurodegenerative damage in MS.

Fingolimod attenuates ovalbumin-induced airway inflammation via inhibiting MAPK/ERK signaling in mice

The current study was designed to investigate the potential anti-inflammatory and antioxidant effects of fingolimod against Ovalbumin (Ova)-induced allergic airway inflammation compared to dexamethasone. Fingolimod was given (0.5 mg/kg/day, p.o.) for sensitized mice 1 h before Ova challenge from Days 19 to 24. Fingolimod significantly inhibited Ova-induced elevation of inflammatory cells and eosinophils numbers in bronchoalveolar lavage fluid (BALF) and reduced concentrations of immunoglobulin E in serum and of sphingosine-1-phosphate, interleukin (IL)-4, and IL-13 in BALF. Fingolimod inhibited microvascular leakage and edema as reflected by the decreased lung/body weight index. These findings were supported by histopathological examination results showing that fingolimod substantially decreased perivascular edema and inflammatory cell infiltration. Fingolimod also attenuated Ova-induced oxidative stress as evidenced by decreased malondialdehyde concentration along with increasing concentrations of reduced glutathione and superoxide dismutase in lung tissues. Fingolimod also significantly decreased monocyte chemoattractant protein-1 (MCP-1), p-ERK, and p-P38 in lung tissues of Ova-challenged mice. In conclusion, the current study demonstrated the anti-inflammatory and antioxidant effects of fingolimod in allergic airway inflammation that might be associated with the downregulation of mitogen activated kinases signaling to decrease T helper 2 cytokine secretion (IL-4 and IL-13) and MCP-1 expression, along with the inhibition of oxidative stress.

MPST deficiency promotes intestinal epithelial cell apoptosis and aggravates inflammatory bowel disease via AKT

Background & aims

Excessive inflammatory responses and oxidative stress are considered the main characteristics of inflammatory bowel disease (IBD). Endogenous hydrogen sulfide (H₂S) has been reported to show anti-inflammatory activity in IBD. The main aim of this study was to explore the role of 3-mercaptopyruvate sulfurtransferase (MPST), a key enzyme that regulates endogenous H₂S biosynthesis, in IBD.

Methods

Colonic MPST expression was evaluated in mice and patients with IBD. Various approaches were used to explore the concrete mechanism underlying MPST regulation of the progression of colitis through in vivo and in vitro models.

Results

MPST expression was markedly decreased in colonic samples from patients with ulcerative colitis (UC) or Crohn's disease (CD) and from mice treated with DSS. MPST deficiency significantly aggravated the symptoms of murine colitis, exacerbated inflammatory responses and apoptosis, and inhibited epithelium stem cell-derived organoid formation in an H₂S-independent manner. Consistently, when HT29 cells were treated with TNF-α, inhibition of MPST significantly increased the expression of proinflammatory cytokines, the amount of ROS and the prevalence of apoptosis, whereas overexpression of MPST markedly improved these effects. RNA-seq analysis showed that MPST might play a role in regulating apoptosis through AKT signaling. Mechanistically, MPST directly interacted with AKT and reduced the phosphorylation of AKT. Additionally, MPST expression was positively correlated with AKT expression in human IBD samples. In addition, overexpression of AKT rescued IEC apoptosis caused by MPST deficiency, while inhibition of AKT significantly aggravated it.

Conclusions

MPST protects the intestines from inflammation most likely by regulating the AKT/apoptosis axis in IECs. Our results may provide a novel therapeutic strategy for the treatment of colitis.

How sphingolipids affect T cells in the resolution of inflammation

The concept of proper resolution of inflammation rather than counteracting it, gained a lot of attention in the past few years. Re-assembly of tissue and cell homeostasis as well as establishment of adaptive immunity after inflammatory processes are the key events of resolution. Neutrophiles and macrophages are well described as promotors of resolution, but the role of T cells is poorly reviewed. It is also broadly known that sphingolipids and their imbalance influence membrane fluidity and cell signalling pathways resulting in inflammation associated diseases like inflammatory bowel disease (IBD), atherosclerosis or diabetes. In this review we highlight the role of sphingolipids in T cells in the context of resolution of inflammation to create an insight into new possible therapeutical approaches.