Design, synthesis, and biological evaluation of novel iNOS inhibitors as potent neuroprotective agents for ischemic stroke.

Ischemic stroke (IS) is characterized by intricate pathophysiological mechanisms, where single-target treatments have often proven insufficient. Thus, multi-target therapeutic approaches are essential for effective IS management. In this study, we employed a molecular hybridization strategy, merging the structures of the iNOS inhibitor 1400W and the multi-target neuroprotective agent NBP, to develop a series of novel iNOS inhibitors BN-1 ∼ BN-4 with neuroprotective properties. Among these, BN-4 exhibited the most potent cell protective activity in OGD/R-induced SH-SY5Y and BV-2 cells. BN-4 not only reduced ROS levels induced by OGD/R in SH-SY5Y cells but also mitigated necrosis and apoptosis. By binding to iNOS in a manner similar to 1400W, BN-4 significantly inhibited iNOS activity. Furthermore, BN-4 demonstrated high stability, excellent blood-brain barrier permeability, and more than 100-fold increase in aqueous solubility compared to NBP. Additionally, BN-4 notably decreased infarct size and showed neuroprotective effects in tMCAO rats. These findings indicate that BN-4 holds promise as a novel candidate for treatment IS, offering enhanced therapeutic efficacy due to its superior pharmacokinetic and pharmacodynamic properties.

Development of Nitric Oxide-Donating Netarsudil Derivatives as a Synergistic Therapy for Glaucoma with Reduced Ocular Irritation.

Based on the synergistic therapeutic effect of nitric oxide (NO) and Rho-associated protein kinase (ROCK) inhibitors on glaucoma, a series of NO-donating Netarsudil derivatives were designed, synthesized, and their activities in vitro and in vivo were evaluated. Among them, (S)-10e released an appropriate amount of NO in aqueous humor in vitro and displayed potent ROCK inhibition. Topical administration of (S)-10e significantly lowered intraocular pressure in an acute ocular hypertension rabbit model and protected retinal ganglion cells in a magnetic microbead occlusion mouse model. A metabolism investigation revealed that (S)-10e released 7a, a metabolite after NO releasing, and 13, an active metabolite of (S)-Netarsudil, in rabbit eyes. Notably, introducing an NO donor moiety attenuated ROCK inhibition-induced ocular irritation in an sGC-independent manner, suggesting that the attenuated conjunctival hyperemia effect of (S)-10e is related to the NO-induced protein S-nitrosation of phosphodiesterase 3A (PDE3A). Overall, (S)-10e is a promising candidate for glaucoma treatment.

Development of Integrated Bioorthogonal Self-Catalyzed NO Donor/Platinum(IV) Prodrugs for Synergistical Intervention against Triple-Negative Breast Cancer.

The platinum(IV) prodrug strategy is attractive for the synergistic antitumor effect. High levels (>400 nM) of nitric oxide (NO) exert promising cancer inhibition effects via multiple mechanisms. Herein, we designed and synthesized a new group of integrated bioorthogonal self-catalyzed NO donor/Pt(IV) prodrugs bearing long alkyl chains to enhance the stability in circulation, while the cytoplasmic reductants trigger cascade activation to release Pt and NO in tumor cells. Specifically, compound 10c exhibited an improved stability, favorable pharmacokinetic properties (AUC(0-t) of 2210.10 h*ng/mL), potent anti-triple-negative breast cancer (TNBC) effects (71.08% tumor growth inhibition (TGI) against the MDA-MB-231 xenograft model), potent in vivo anti-TNBC lung metastasis activity, and acceptable low toxicity. Importantly, NO released from 10c leads to the S-nitrosation of metal transporters Atox1&ATP7a in TNBC cells, which increases the Pt retention and inhibits lysyl oxidase, generating synergistic tumoricidal and antimetastatic activity. These results may inspire further study on the synergistical therapy of Pt and NO for the treatment of TNBC.

Advances in nitric oxide regulators for the treatment of ischemic stroke.

Ischemic stroke (IS) is a life-threatening disease worldwide. Nitric oxide (NO) derived from l-arginine catalyzed by NO synthase (NOS) is closely associated with IS. Three isomers of NOS (nNOS, eNOS and iNOS) produce different concentrations of NO, resulting in quite unlike effects during IS. Of them, n/iNOSs generate high levels of NO, detrimental to brain by causing nerve cell apoptosis and/or necrosis, whereas eNOS releases small amounts of NO, beneficial to the brain via increasing cerebral blood flow and improving nerve function. As a result, a large variety of NO regulators (NO donors or n/iNOS inhibitors) have been developed for fighting IS. Regrettably, up to now, no review systematically introduces the progresses in this area. This article first outlines dynamic variation rule of NOS/NO in IS, subsequently highlights advances in NO regulators against IS, and finally presents perspectives based on concentration-, site- and timing-effects of NO production to promote this field forward.

A Novel Hybrid of Telmisartan and Borneol Ameliorates Neuroinflammation and White Matter Injury in Ischemic Stroke Through ATF3/CH25H Axis.

Cerebral ischemic stroke causes substantial white matter injury, which is further aggravated by neuroinflammation mediated by microglia/astrocytes. Given the anti-neuroinflammatory action of telmisartan and the enhancing blood-brain barrier (BBB) permeability potential of resuscitation-inducing aromatic herbs, 13 hybrids (3a-m) of telmisartan (or its simplified analogues) with resuscitation-inducing aromatic agents were designed, synthesized, and biologically evaluated. Among them, the optimal compound 3a (the ester hybrid of telmisartan and (+)-borneol) potently inhibited neuroinflammation mediated by microglia/astrocytes and ameliorated ischemic stroke. Particularly, 3a significantly conferred protection for white matter integrity after cerebral ischemic stroke via decreasing abnormally dephosphorylated neurofilament protein, upregulating myelin basic protein, and attenuating oligodendrocyte damage. Further RNA-sequencing data revealed that 3a upregulated expression of transcriptional regulator ATF3 to reduce the expression of CH25H, prevented proinflammatory state of lipid-droplet-accumulating microglia/astrocytes to limit excessive inflammation, and eventually protected neighboring oligodendrocytes to prevent white matter injury. Taken with the desirable pharmacokinetics behavior and improved brain distribution, 3a may be a feasible therapeutic agent for ischemic stroke and other neurological disorders with white matter injury.

One Stone Two Birds: Redox-Sensitive Colocalized Delivery of Cisplatin and Nitric Oxide through Cascade Reactions.

Bio-orthogonal bond-cleavage reactions have been used in cancer therapy for improving the biological specificity of prodrug activation, but the spatiotemporal consistency of reactants is still a huge challenge. Although, in most cases, the cleavage catalysts and caged prodrugs are administrated separately, it is difficult to avoid the reactions in advance before they meet at the tumor site. Herein, we design and construct novel coordinative nanoparticles, integrating two prodrugs A and B as ligands and ferric ions as coordinative centers. After nanoparticles accumulated in tumor through passive targeting, inert Pt(IV) prodrug A is specifically and spontaneously reduced into active Pt(II) cisplatin, which acts as the cleavage catalyst to subsequently initiate the in situ bio-orthogonal depropargylation of B, that is, O 2-propargyl nitric oxide (NO) donor. The unique structure of coordinative nanoparticles ensures the spatiotemporal consistency of reactants (prodrugs A and B) and products (cytotoxic cisplatin and tumoricidal NO) for the bio-orthogonal bond-cleavage reaction, which leads to an improved synergistic therapeutic activity for triple-negative breast cancer (TNBC). This new concept of bio-orthogonal dual-prodrug coordinative nanoparticles may inspire further applications in bio-orthogonal chemistry and drug delivery for combination chemotherapy.

Synthesis and biological evaluation of hybrids from optically active ring-opened 3-N-butylphthalide derivatives and 4-fluro-edaravone as potential anti-acute ischemic stroke agents.

The treatment of acute ischemic stroke (AIS) remains a tough challenge in clinic. Here, we report the anti-AIS activity of R- and S-FMPB generated from hybridization of ring-opened R- and S-3-N-butylphthalide (R- and S-NBP) derivatives (R- and S-APB) with 4-fluro-edaravone (4-F-Eda), respectively. S-FMPB (10 mg/kg, iv) significantly improved the neurological score and alleviated cerebral infarction and edema of rats suffered from transient middle cerebral artery occlusion (tMCAO), superior to RS- and R-FMPB, as well as better than RS-FMPB by oral administration in previous studies. Importantly, S-FMPB is more active not only than the equimolar S-APB and 4-F-Eda alone or in combination but also than the clinical drugs NBP and edaravone (Eda) in combination at the equimolar doses. Furthermore, S-FMPB showed relative stability in plasma or liver microsome of rats but could be converted into two active metabolites (S-NBP and 4-F-Eda) in rats with good pharmacokinetic properties in terms of longer half-life period (t1/2) and mean residence time (MRT) as well as larger area under the concentration-time curve (AUC) of S-NBP than those from S-NBP and 4-F-Eda single or in combination by iv administration, suggesting that S-NBP and 4-F-Eda may synergistically play the anti-AIS activity. Our findings suggest that S-FMPB may be used as a potential anti-AIS agent to further study.