Synthesis and anti-inflammatory activity of novel firocoxib analogues with balanced COX inhibition

The adverse effects caused by nonselective and selective cyclooxygenase-2 (COX-2) inhibitors remain a challenge for current anti-inflammatory medications. A balanced inhibition of COX-1/-2 represents a promising strategy for the development of novel COX-2 inhibitors. In this study, we present the design and synthesis of a novel series of firocoxib analogues incorporating an amide bond to facilitate essential hydrogen bonding with amino residues in COX-2. The synthesized analogs were evaluated for their inhibitory activity against both COX-1 and COX-2 enzymes. Among them, compound 9d demonstrated potent and balanced inhibition. Inhibition of COX enzymes by 9d in lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophages resulted in the suppression of the NF-κB signaling pathway to reduced expression of pro-inflammatory factors such as inducible nitric oxide synthase (iNOS), COX-2, nitric oxide (NO), and reactive oxygen species (ROS). The remarkable in vitro anti-inflammatory activity exhibited by 9d positions it as a promising candidate for further development as a novel lead compound for inflammation treatment.

Design of Balanced Cyclooxygenase Inhibitors Based on Natural Anti-inflammatory Ascidian Metabolites and Celecoxib

The serious adverse effects caused by non-selective and selective cyclooxygenase-2 (COX-2) inhibitors remain significant concerns for current anti-inflammatory drugs. In this study, we present the design and synthesis of a novel series of celecoxib analogs incorporating a hydrazone linker, which were subjected to in silico analysis to compare their binding poses with those of clinically used nonsteroidal anti-inflammatory drugs (NSAIDs) against COX-1 and COX-2. The synthesized analogs were evaluated for their inhibitory activity against both COX enzymes, and compound 6 m, exhibiting potent balanced inhibition, was selected for subsequent in vitro anti-inflammatory assays. Treatment with 6 m effectively suppressed the NF-κB signaling pathway in lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophages, resulting in reduced expression of pro-inflammatory factors such as inducible nitric oxide synthase (iNOS), COX-2, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, as well as decreased production of prostaglandin E2 (PGE2 ), nitric oxide (NO), and reactive oxygen species (ROS). However, 6 m has no effect on the MAPK signaling pathway. Therefore, due to its potent in vitro anti-inflammatory activity coupled with lack of cytotoxicity, 6 m represents a promising candidate for further development as a new lead compound targeting inflammation.

Impact of correlated synaptic input on output firing rate and variability in simple neuronal models

Cortical neurons are typically driven by thousands of synaptic inputs. The arrival of a spike from one input may or may not be correlated with the arrival of other spikes from different inputs. How does this interdependence alter the probability that the postsynaptic neuron will fire? We constructed a simple random walk model in which the membrane potential of a target neuron fluctuates stochastically, driven by excitatory and inhibitory spikes arriving at random times. An analytic expression was derived for the mean output firing rate as a function of the firing rates and pairwise correlations of the inputs. This stochastic model made three quantitative predictions. (1) Correlations between pairs of excitatory or inhibitory inputs increase the fluctuations in synaptic drive, whereas correlations between excitatory-inhibitory pairs decrease them. (2) When excitation and inhibition are fully balanced (the mean net synaptic drive is zero), firing is caused by the fluctuations only. (3) In the balanced case, firing is irregular. These theoretical predictions were in excellent agreement with simulations of an integrate-and-fire neuron that included multiple conductances and received hundreds of synaptic inputs. The results show that, in the balanced regime, weak correlations caused by signals shared among inputs may have a multiplicative effect on the input-output rate curve of a postsynaptic neuron, i.e. they may regulate its gain; in the unbalanced regime, correlations may increase firing probability mainly around threshold, when output rate is low; and in all cases correlations are expected to increase the variability of the output spike train.