Anti-inflammatory, anti-nociceptive and anti-pyretic activities of Cenchrus ciliaris L.

ETHNOPHARMACOLOGICAL RELEVANCE: Cenchrus ciliaris L. belongs to the family Poaceae and is found all over the world. It is native to the Cholistan desert of Pakistan where it is locally known as 'Dhaman'. Owing to high nutritional value, C. ciliaris is used as fodder while seeds are used for bread making which are consumed by locals. It also possesses medicinal value and is extensively employed to treat pain, inflammation, urinary tract infection, and tumors. AIM OF STUDY: Studies on the pharmacological activities of C. ciliaris are scarce in spite of its several traditional uses. To the best of our knowledge, no comprehensive study has been conducted on anti-inflammatory, analgesic and anti-pyretic activity of C. ciliaris until now. Here we employed an integrative phytochemical and in - vivo framework to evaluate the potential biological activities of C. ciliaris against inflammation, nociception and pyrexia experimentally induced in rodents. MATERIAL AND METHODS: C. ciliaris was collected from the desert of Cholistan, Bahawalpur, Pakistan. Phytochemical profiling of C. ciliaris was done by employing GC-MS analysis. Anti-inflammatory activity of plant extract was initially determined by various in - vitro assays including albumin denaturation assay and RBC membrane stabilization assays. Finally, rodents were utilized to evaluate in - vivo anti-inflammatory, antipyretic and anti-nociceptive activities. RESULTS: Our data revealed the presence of 67 phytochemicals in methanolic extract of C. ciliaris. The methanolic extract of C. ciliaris provided RBC membrane stabilization by 65.89 ± 0.32% and protection against albumin denaturation by 71.91 ± 3.42% at 1 mg/ml concentration. In in - vivo acute inflammatory models, C. ciliaris exhibited 70.33 ± 1.03, 62.09 ± 8.98, 70.24 ± 0.95% anti-inflammatory activity at concentration of 300 mg/ml against carrageenan, histamine and serotonin induced inflammation. In CFA induced arthritis, inhibition of inflammation was found to be 48.85 ± 5.11% at 300 mg/ml dose after 28 days of treatment. In anti-nociceptive assays C. ciliaris exhibited significant analgesic activity in both peripheral and centrally mediated pain. The C. ciliaris also reduced the temperature by 75.26 ± 1.41% in yeast induced pyrexia. CONCLUSION: C. ciliaris exhibited anti-inflammatory effect against acute and chronic inflammation. It also showed significant anti-nociceptive and anti-pyretic activity which endorses its traditional use in the management of pain and inflammatory disorders.

Altered membrane rigidity via enhanced endogenous cholesterol synthesis drives cancer cell resistance to destruxins.

Destruxins, secondary metabolites of entomopathogenic fungi, exert a wide variety of interesting characteristics ranging from antiviral to anticancer effects. Although their mode of action was evaluated previously, the molecular mechanisms of resistance development are unknown. Hence, we have established destruxin-resistant sublines of HCT116 colon carcinoma cells by selection with the most prevalent derivatives, destruxin (dtx)A, dtxB and dtxE. Various cell biological and molecular techniques were applied to elucidate the regulatory mechanisms underlying these acquired and highly stable destruxin resistance phenotypes. Interestingly, well-known chemoresistance-mediating ABC efflux transporters were not the major players. Instead, in dtxA- and dtxB-resistant cells a hyper-activated mevalonate pathway was uncovered resulting in increased de-novo cholesterol synthesis rates and elevated levels of lanosterol, cholesterol as well as several oxysterol metabolites. Accordingly, inhibition of the mevalonate pathway at two different steps, using either statins or zoledronic acid, significantly reduced acquired but also intrinsic destruxin resistance. Vice versa, cholesterol supplementation protected destruxin-sensitive cells against their cytotoxic activity. Additionally, an increased cell membrane adhesiveness of dtxA-resistant as compared to parental cells was detected by atomic force microscopy. This was paralleled by a dramatically reduced ionophoric capacity of dtxA in resistant cells when cultured in absence but not in presence of statins. Summarizing, our results suggest a reduced ionophoric activity of destruxins due to cholesterol-mediated plasma membrane re-organization as molecular mechanism underlying acquired destruxin resistance in human colon cancer cells. Whether this mechanism might be valid also in other cell types and organisms exposed to destruxins e.g. as bio-insecticides needs to be evaluated.

Identification of phosphorylation sites and binding pockets for modulation of NaV 1.5 channel by Fyn tyrosine kinase.

Cardiac sodium channel NaV 1.5 is the predominant form of sodium channels in cardiomyocytes, which exists as a macromolecular complex and interacts with multiple protein partners. Fyn kinase is one of the interacting proteins which colocalize, phosphorylate and modulate the NaV 1.5 channel. To elaborate this interaction we created expression vectors for the N-terminal, intracellular loop, and C-terminal regions of the NaV 1.5 channel, to express in HEK-293 cells. By co-immunoprecipitation and anti-phosphotyrosine blotting, we identified proline-rich binding sites for Fyn kinase in the N-terminal, IC-loopi-ii and C-terminal. After binding, Fyn kinase phosphorylates tyrosine residues present in the N- and C-terminal, which produce a depolarizing shift of 7 mV in fast inactivation. The functional relevance of these binding and phosphorylation sites was further underpinned by creating full length mutants masking these sites sequentially. An activation and inactivation curves were recorded with or without co-expressed Fyn kinase which indicates that phosphorylation of tyrosine residues at positions 68, 87, 112 in the N-terminal and at positions 1811 and 1889 in the C-terminal creates a depolarizing shift in fast inactivation of NaV 1.5 channel.

TNF Lectin-Like Domain Restores Epithelial Sodium Channel Function in Frameshift Mutants Associated with Pseudohypoaldosteronism Type 1B.

Previous in vitro studies have indicated that tumor necrosis factor (TNF) activates amiloride-sensitive epithelial sodium channel (ENaC) current through its lectin-like (TIP) domain, since cyclic peptides mimicking the TIP domain (e.g., solnatide), showed ENaC-activating properties. In the current study, the effects of TNF and solnatide on individual ENaC subunits or ENaC carrying mutated glycosylation sites in the α-ENaC subunit were compared, revealing a similar mode of action for TNF and solnatide and corroborating the previous assumption that the lectin-like domain of TNF is the relevant molecular structure for ENaC activation. Accordingly, TNF enhanced ENaC current by increasing open probability of the glycosylated channel, position N511 in the α-ENaC subunit being identified as the most important glycosylation site. TNF significantly increased Na+ current through ENaC comprising only the pore forming subunits α or δ, was less active in ENaC comprising only ß-subunits, and showed no effect on ENaC comprising γ-subunits. TNF did not increase the membrane abundance of ENaC subunits to the extent observed with solnatide. Since the α-subunit is believed to play a prominent role in the ENaC current activating effect of TNF and TIP, we investigated whether TNF and solnatide can enhance αßγ-ENaC current in α-ENaC loss-of-function frameshift mutants. The efficacy of solnatide has been already proven in pathological conditions involving ENaC in phase II clinical trials. The frameshift mutations αI68fs, αT169fs, αP197fs, αE272fs, αF435fs, αR438fs, αY447fs, αR448fs, αS452fs, and αT482fs have been reported to cause pseudohypoaldosteronism type 1B (PHA1B), a rare, life-threatening, salt-wasting disease, which hitherto has been treated only symptomatically. In a heterologous expression system, all frameshift mutants showed significantly reduced amiloride-sensitive whole-cell current compared to wild type αßγ-ENaC, whereas membrane abundance varied between mutants. Solnatide restored function in α-ENaC frameshift mutants to current density levels of wild type ENaC or higher despite their lacking a binding site for solnatide, previously located to the region between TM2 and the C-terminus of the α-subunit. TNF similarly restored current density to wild type levels in the mutant αR448fs. Activation of ßγ-ENaC may contribute to this moderate current enhancement, but whatever the mechanism, experimental data indicate that solnatide could be a new strategy to treat PHA1B.