Biology subjects

Deng, S.-X.

Publications and source records attributed to Deng, S.-X..

5 recordsLinked to original sources

bioRxiv2026

A non-retinoid triazolopyrimidine RBP4 antagonist for the treatment of Stargardt disease

Stargardt disease is a juvenile-onset retinal dystrophy characterized by the buildup of cytotoxic lipofuscin deposits in the retinal pigment epithelium (RPE), leading to photoreceptor degeneration and eventual blindness. Currently, there are no FDA-approved treatments for Stargardt disease. Bisretinoids, byproducts of the visual cycle, are the major cytotoxic components of the lipofuscin deposits, and bisretinoid synthesis relies on the traffic of retinol from the bloodstream to the retina. Selective targeting of the key retinol transporter, Retinol-Binding Protein 4 (RBP4), offers an appealing strategy for halting the buildup of lipofuscin in the RPE and arresting the progression of Stargardt disease. Retinol delivery depends on RBP4 interaction with another serum protein, Transthyretin (TTR). We previously reported several libraries of RBP4 antagonists that effectively blocked the association of the TTR-RBP4-retinol tertiary complex, thereby lowering the overall retinol load in the retina; however, some chemotypes displayed off-target activity that warranted further optimization. Here, we report the pharmacological characterization of AKR-XI-85 and its analogs as promising non-retinoid small-molecule RBP4 antagonists. AKR-XI-85 displayed excellent in vitro and in vivo efficacy and desirable pharmacokinetic properties without any limiting off-target activity. In Abca4-/- mice, chronic dosing of the compound induced a prolonged reduction in serum RBP4 levels and achieved a dramatic, 70 % reduction in the accumulation of A2E, a critical component of toxic lipofuscin. As such, AKR-XI-85 may be an attractive drug candidate for the treatment of Stargardt disease and other lipofuscin-dependent retinopathies.

pharmacology and toxicology↗

bioRxiv2025

Novel, small molecules targeting the 5-HT4R receptor protect against stress-induced maladapative behavior with efficacy across age

BACKGROUNDStress is a risk factor for developing psychiatric disorders, including major depressive disorder (MDD). Compounds targeting the serotonin type 4 receptor (5-HT4R) hold promise as novel rapid-acting treatments of mood disorders. However, a lack of selectivity and numerous side effects have been limiting factors for their clinical use. Here, we developed and characterized novel-composition 5-HT4R compounds in mouse models of stress. METHODSThree 5-HT4R-targeting compounds were designed and synthesized based on PF-04995274, a high-affinity 5-HT4R ligand reported to be a partial agonist. G-protein assays were utilized to characterize molecular activity. Saline, PF-04995274, or a novel compound were administered before or after stress in male and female mice. Drug effects were assayed using behavioral paradigms. Patch clamp electrophysiology was used to determine the effect of drug on glutamatergic activity in hippocampal Cornu Ammonis 3 (CA3). RESULTSProphylactic administration of DL5, DL7, or DL8 was effective at reducing stress-induced maladaptive behaviors in male and female mice; DL7 and DL8 were effective when administered after stress. When administered following learned helplessness (LH), DL7 reduced behavioral despair and increased c-Fos in the dentate gyrus (DG) and CA3. All novel compounds attenuated large-amplitude AMPA receptor-mediated bursts in ventral CA3 (vCA3). In aged male mice, prophylactic DL7 reduced behavioral despair. CONCLUSIONSThese results characterize novel 5-HT4R-targeting compounds for stress-induced psychiatric disease with the potential to address unmet needs in adult and aged patients with stress-induced psychiatric illness. Future work will characterize their mechanism of action with the goal of clinical development.

neuroscience↗

bioRxiv2025

Design and Synthesis of Potent First-in-Class Histones Acetyltransferase Modulators.

Epigenetic regulation governs gene expression through histone modifications, particularly the acetylation of lysine residues. These modifications are orchestrated by enzymes such as histone acetyltransferases (HATs) and histone deacetylases (HDACs). Among them, p300 plays a critical role in various disorders such as neurodegenerative conditions (i.e. Alzheimers disease, and Alzheimers Disease related dementia) and cancer (i.e. glioblastoma and B cell lymphoma). Our aim is to develop therapeutic interventions for these ailments. In this context, we designed and synthesized novel activators of the enzyme. Using an in vitro screening approach combined with structural activity relationship analysis, we successfully identified compounds that modulate histone acetylation.

biochemistry↗

bioRxiv2024

Platelet integrin αIIbβ3 plays a key role in venous thrombogenesis in a mouse model

AbstractVenous thrombosis (VT) is a common vascular disease associated with reduced survival and a high recurrence rate. Previous studies have shown that the accumulation of platelets and neutrophils at sites of endothelial cell activation is a primary event in VT, but a role for platelet IIb{beta}3 in the initiation of venous thrombosis has not been established. This task has been complicated by the increased bleeding linked to partial agonism of current IIb{beta}3 inhibitory drugs such as tirofiban (Aggrastat(R)). Here, we show that m-tirofiban, an engineered version of tirofiban, is not a partial agonist of IIb{beta}3. This is based on its cryo-EM structure in complex with human full-length IIb{beta}3 and its inability to increase expression of an activation-sensitive epitope on platelet IIb{beta}3. m-tirofiban abolished agonist-induced platelet aggregation ex vivo at concentrations that preserved clot retraction and markedly suppressed the accumulation of platelets, neutrophils, and fibrin on thrombin-activated endothelium in real-time using intravital microscopy in a mouse model of venous thrombogenesis. Unlike tirofiban, however, m-tirofiban did not increase bleeding at the thrombosis-inhibitory dose. These findings establish a key role for IIb{beta}3 in the initiation of VT, provide a guiding principle for designing potentially safer inhibitors for other integrins, and suggest that pure antagonists of IIb{beta}3 like m-tirofiban merit further consideration as potential thromboprophylaxis agents in patients at high-risk for VT and hemorrhage.

pathology↗

bioRxiv2019

Ovarian hormones mediate the prophylactic efficacy of (R,S)-ketamine and (2R,6R)-hydroxynorketamine in female mice

BACKGROUNDFemales are more likely than males to develop major depressive disorder (MDD) after exposure to stress. We previously reported that the administration of (R,S)-ketamine before stress can prevent stress-induced depressive-like behavior in male mice but have yet to assess efficacy in female mice or for other compounds, such as the metabolites of (R,S)-ketamine.\n\nMETHODSWe administered (R,S)-ketamine or its metabolites (2R,6R)-hydroxynorketamine ((2R,6R)-HNK) and (2S,6S)-HNK at various doses 1 week before one of a number of stressors, including contextual fear conditioning (CFC), learned helplessness (LH), and chronic immobilization stress (CIS), in male and female 129S6/SvEv mice. To examine the interaction between ovarian hormones and stress resilience, female mice also underwent ovariectomy surgery (OVX) and a hormone replacement protocol prior to drug administration.\n\nRESULTS(R,S)-ketamine and (2S,6S)-HNK, but not (2R,6R)-HNK, attenuated learned fear in male mice. (R,S)-ketamine and (2R,6R)-HNK, but not (2S,6S)-HNK, significantly reduced stress-induced depressive-like behavior in male and female mice. (R,S)-ketamine and (2R,6R)-HNK) were prophylactically effective at a lower dose (10 mg/kg and 0.025 mg/kg, respectively) in female mice than in male mice (30 mg/kg and 0.075 mg/kg, respectively). Moreover, ovarian-derived hormones were necessary and sufficient for prophylaxis in female mice.\n\nCONCLUSIONSOur results suggest that prophylactics against stress-induced depressive-like behavior can be developed in a sex-specific manner and that ovarian hormones mediate prophylactic efficacy in females. To our knowledge, this is the first demonstration of the prophylactic efficacy of the metabolites of (R,S)-ketamine in male and female mice.

neuroscience↗