ACS Chemical Neuroscience最新文献

Photopharmacology, which enables the precise optical control of endogenous receptor activity, represents a powerful approach in neuroscience. However, photochromic diffusible ligands often exhibit limited subtype specificity, while alternative strategies for controlling specific receptor subtypes require genetic modification. Here, to achieve high subtype selectivity without the need of receptor engineering, we introduce a genetically independent strategy for optical control of endogenous receptors based on highly selective and chemically defined photoswitchable nanobodies. By covalently coupling a light-sensitive azobenzene agonist to a high-affinity nanobody targeting α7 nicotinic acetylcholine receptor (nAChR), we engineered MalAzoCh-C4, an optonanobody that confers reversible, light-dependent activation of native α7 receptors. In Xenopus oocytes, MalAzoCh-C4 enables wavelength-controlled modulation of recombinant α7 receptors, with enhanced activity in trans configuration. In acute hippocampal slices, application of MalAzoCh-C4 produces robust photocontrol of endogenous α7 nAChRs in interneurons, sufficient to modulate action potential firing. This strategy combines nanobody specificity with the temporal resolution of photopharmacology, establishing optonanobodies as a platform for control of native neuronal receptors.

Synthetic cannabinoid receptor agonists (SCRAs) are a major health challenge. Indazole-based SCRAs continue to evolve through modification of tail and linked groups, although they have mostly been tested under different conditions by different laboratories and their pharmacokinetic properties have been little studied. We prepared and pharmacologically characterized a library of 57 indazole SCRAs combining varying aliphatic N-alkyl tail groups along with common linked groups (e.g., naphthyl, cumyl, adamantyl, and amino-acid-derived motifs). Compounds were profiled for CB₁/CB₂ binding affinity, functional activity in calcium mobilization assays, and β-arrestin-2 recruitment, followed by human and mouse liver microsomal stability. Extending short aliphatic tails to n-butyl/n-pentyl generally increased CB₁ affinity and functional potency, while linkedgroups contributed toward subtype selectivity and signaling, yielding multiple high-efficacy agonists at both receptors. Microsomal studies revealed species differences, with substantially faster clearance in mice than humans for many analogs. Selected potent compounds were advanced to mouse pharmacokinetic studies. Many compounds demonstrated rapid systemic exposure and brain penetrance. Together, these results define structure–activity relationships for indazole SCRAs and support prioritization of emerging analogs with high CB₁ efficacy and favorable CNS exposure for further characterization in vivo.

α-Synuclein (αS) is a highly charged, intrinsically disordered protein (IDP) whose aberrant aggregation is linked to Parkinson’s disease (PD). Along with wild-type (WT) αS, five single-point mutants (A30P, E46K, H50Q, G51D, and A53T) are implicated in familial PD. To resolve contradictory experimental observations under varying solution conditions, we investigated how ionic strength modulates the relative aggregation propensity of these six monomeric αS variants using atomistic simulations. Structural and energetic analyses at global, domain, and residue levels revealed that aggregation propensity rankings switch with increasing ionic strength but stabilize beyond physiological concentration, while A53T and H50Q consistently remain highly aggregation-prone. We additionally identified electrostatic-driven decoupling between global and local motions. Aggregation-prone monomers preferentially populate semicompact ensembles with β-sheet propensity, an exposed and stiff N-terminus with fewer interdomain contacts, a flexible yet compact C-terminus, and an NAC domain that is either under-protected and stiff or flexible and poorly hydrated. These monomers further exhibit strong intramolecular stabilization, poor solvation, counterion binding, and subdiffusive collapsing dynamics that may facilitate intermolecular encounters. We justified aggregation propensity trends across ionic strengths, validated physiological trends using a dimer model, suggested a generic monomer-to-aggregate mechanism, and reconciled simulations with experimental variability.

Nitazenes are emerging synthetic opioids that exhibit exceptionally high potency at the μ-opioid receptor (MOR) and contribute to rising overdose fatalities worldwide. Despite extensive in vitro profiling, the structural determinants underlying their structure–activity relationships (SARs) remain unresolved. Here, we combine functional profiling with quantum mechanical calculations and molecular dynamics (MD) simulations to establish a MOR structure-based SAR for nitazenes. Across functional assays, systematic variation at the R1, R2, and R3 positions revealed nonadditive effects on potency and identified optimal R1 chain length, R2 N-desethylation, and retention of the 5-nitro group as key determinants of high MOR potency. Consistent with this framework, N-desethyl isotonitazene emerged as the most potent analogue. Structural analysis of the cryo-EM MOR–G_i–fluornitrazene complex, together with MD simulations of multiple nitazene analogues, revealed a conserved trivalent binding architecture in which each substituent engages distinct subpockets. N-desethylation at R2 increases the positive electrostatic surface at the protonated amine, reduces steric constraints near transmembrane helix (TM) 7, strengthens R3 interactions, and allosterically modulates R1 engagement in a substituent-dependent manner. Additionally, optimal R1 chain length and shape stabilize the TM5–TM6 interface and influence activation-relevant TM6 dynamics, defining a unified SAR at R1 across nitazene and fentanyl scaffolds. Together, these findings indicate that nitazene potency reflects substituent-dependent coupling among R1, R2, and R3 within the MOR binding pocket, with R3 engagement distinguishing nitazenes from fentanyl. This framework establishes a coherent structural model of nitazene–MOR recognition that accounts for their unusually high potency and efficacy.

Alzheimer’s disease (AD) is a degenerative disease of the central nervous system (CNS), which is relatively common in the elderly population and is the main cause of senile dementia. Its typical pathological features mainly lie in hyperphosphorylated tau proteins in the form of neurofibrillary tangles (referred to as tau tangles) and β-amyloid plaques. Using DrugCLIP website, we investigated the effects of butyrylcholinesterase (BChE) inhibitors on AD. From virtual screening, molecule W1 (inhibitory concentration (IC₅₀) = 0.63 ± 0.19 μM) was identified as the lead compound of this research. Subsequently, the lead compound molecule was obtained through chemical synthesis, and its structure was modified to synthesize and evaluate 21 derivatives. Derivatives W3 and W13 also showed micromolar-level BChE inhibitory activity (W3: IC₅₀ = 0.28 ± 0.14 μM, W13: IC₅₀ = 0.03 ± 0.02 μM), with W13 demonstrating superior inhibitory activity. The results of binding patterns demonstrated that both compounds can bind to the target and form multiple interactions with amino acid residues. From the enzyme kinetics results, it can be observed that both compounds were BChE inhibitors in a mixed manner, which was consistent with the docking results. Due to W3 not occupying the acyl-binding pocket, its activity was inferior to W13. In pharmacodynamic studies, W3 and W13 protected nerve cells from toxicity, hydrogen peroxide (H₂O₂), and Aβ_1–42 stimulation in vitro, reduced the production of reactive oxygen species, and alleviated Aβ-induced cognitive impairment in mice. In addition, optimal compound W13 presented considerable pharmacokinetic properties, with a high oral bioavailability (80%). Moreover, it could penetrate the blood–brain barrier and take effect in the CNS. Therefore, these findings support further investigation of W3 and W13 as potential therapeutic candidates for advanced AD.

The synaptic vesicle protein SV2C, predominantly found in the basal ganglia, has been associated with Parkinson’s disease through genetic studies. It plays a crucial role in regulating dopamine release and has been shown to be disrupted in PD animal models and brain tissues from PD patients. In the context of PD-related synaptopathy, SV2C may serve as a potential imaging target for monitoring disease progression and response to treatment. [¹⁸F]UCB-F is a radioligand binding to SV2C developed by UCB. Preliminary autoradiography and PET studies in rats showed that [¹⁸F]UCB-F displays a brain distribution consistent with the expression of SV2C in vitro but does not display any specific binding in vivo. This study was therefore designed to further investigate the affinity and selectivity of [¹⁸F]UCB-F for SV2C and to examine the in vitro and in vivo properties of the radioligand in nonhuman primates. In vitro binding studies were performed to measure the affinity of UCB-F to SV2A, SV2B, and SV2C. In-silico modeling was used to assess the binding mode and energy of UCB-F. Autoradiography studies on rat and nonhuman primate (NHP) brain tissues were performed to confirm that [¹⁸F]UCB-F showed similar distribution in rat and NHP tissue. Finally, PET studied in NHPs were performed to examine the in vivo pharmacokinetic properties of [¹⁸F]UCB-F. [¹⁸F]UCB-F was successfully synthesized from the corresponding precursor with high yield. Autoradiography on brain slices from rats and NHPs demonstrated specific binding of [¹⁸F]UCB-F in the pallidum, striatum, substantia nigra, and brainstem, consistent with the known brain expression of SV2C. In NHPs, [¹⁸F]UCB-F rapidly crossed the blood-brain barrier, reaching peak uptake values of 2.8%ID in NHP1 and 2.1%ID in NHP2 at 4 min postinjection. The tracer was rapidly washed out from the brain, with no clear regional distribution. Radiometabolite analysis revealed the formation of only more polar radiometabolites, with approximately 15% of unchanged radioligand remaining in plasma at 15 min postinjection. In vitro and in-silico studies demonstrated that the affinity of [¹⁸F]UCB-F decreased by approximately one factor of magnitude with increase of temperature from 277 K (4 °C) to 310 K (37 °C). This temperature-related decrease of the affinity for SV2C together with rapid in vivo radiometabolism might explain the discrepancy between in vitro and in vivo performance of [¹⁸F]UCB-F. Overall, these findings suggest that [¹⁸F]UCB-F is not a suitable PET radioligand for imaging SV2C. Further research is needed to identify alternative candidates with improved in vivo stability and brain retention.

Positive allosteric modulators (PAMs) of the M1 muscarinic acetylcholine receptor (mAChR) have progressed into clinical trials for cognitive disorders, such as Alzheimer’s disease and schizophrenia. However, their successful translation has been limited by on-target cholinergic adverse effects. These limitations have been attributed to excessive allosteric agonism, however, the contribution of allosteric cooperativity, efficacy modulation and receptor regulatory mechanisms remains poorly defined. Here, we performed a comparative pharmacological analysis of five structurally distinct M1 PAMs (BQCA, MK-7622, PF-06767832, MIPS1780 and VU0486846) in HEK293A cells expressing the human M1 mAChR (hM1-WT) or a phosphorylation site-deficient human M1 mAChR (hM1-PD). Radioligand binding and functional assays were used to quantify binding affinity and cooperativity, as well as allosteric agonism and efficacy modulation on G protein-dependent and β-arrestin-associated pathways. Uniquely, VU0486846, previously reported to lack cholinergic adverse effects, displayed consistently low allosteric agonism, weaker binding and functional cooperativity but comparable efficacy modulation across all signaling pathways. In contrast, PAMs associated with cholinergic adverse effects had higher allosteric agonism, stronger cooperativity and preferential enhancement of β-arrestin-associated signaling. Removing the M1 mAChR phosphorylation sites uncoupled allosteric agonism from efficacy modulation for most M1 PAMs, with the loss of phosphorylation acting as a key regulator of allosteric signaling at the M1 mAChR. Together these results suggest that low allosteric agonism and balanced efficacy modulation may be essential for improved tolerability of M1 PAMs. This work provides a mechanistic framework for differentiating M1 PAM pharmacology beyond intrinsic agonism alone and may inform the design of safer M1-targeted therapeutics.

Sleep deprivation is a global health concern that disrupts hippocampal proteostasis and leads to cognitive decline. Heat shock protein 70 (HSP70), a key molecular chaperone supporting neuronal survival, is downregulated under sleep deprivation, yet its regulatory mechanisms remain unclear. A murine sleep deprivation model was established using the multiple-platform method. Cognitive performance was assessed with the Y-maze and novel object recognition tests. Western blotting, qRT-PCR, cycloheximide (CHX) chase, and coimmunoprecipitation assays were performed to examine the regulation of HSP70 by the E3 ligase UBOX5. In vivo, mice with UBOX5 knockout were treated with sleep deprivation, followed by behavioral testing and enzyme-linked immunosorbent assay measurement of hippocampal cytokines. Sleep deprivation produced a duration-dependent decline in memory and recognition, accompanied by reduced hippocampal HSP70 and increased UBOX5 expression. In vitro, UBOX5 overexpression decreased, whereas knockdown increased HSP70 protein abundance without altering transcript levels. CHX chase assays confirmed accelerated degradation, and coimmunoprecipitation demonstrated UBOX5-dependent, UBE2M-mediated polyubiquitination of HSP70. Knockout of UBOX5 attenuated sleep deprivation-induced cognitive impairment and neuroinflammation. UBOX5 destabilizes HSP70 via ubiquitination, promoting sleep deprivation-induced neuroinflammation and cognitive dysfunction. These findings support the UBOX5/HSP70 axis as a novel mechanistic link between sleep deprivation and neuronal injury, and a potential therapeutic target.

Previously, we reported the potent and highly selective M₁ antagonists VU0415248 and VU0452865; however, these compounds were limited by high predicted hepatic clearance in rat. This work reports the development of cyclobutylsulfonamide-based analogs of VU0415248 and VU0452865. From this exercise, we identified VU6077564, a peripherally restricted and selective M₁ antagonist. Furthermore, we demonstrate the ability of VU6077564 to promote neurite outgrowth in adult rat dorsal root ganglia sensory neurons, highlighting the potential of selective M₁ antagonists for the treatment of peripheral neuropathy.

The intercellular transmission of pathological markers is of great significance for understanding the occurrence and progression of neurodegenerative diseases. Over the past decade, numerous excellent reviews have been published concerning intercellular communication, comprehensively summarizing the key mechanisms by which pathological proteins propagate in these diseases. Building upon this foundation, the present review aims to provide an updated synthesis of the latest advances in this rapidly evolving field. We elaborate on recent discoveries in intercellular communication patterns in neurodegenerative diseases, starting with exploring intercellular communication mediated by extracellular vesicles and other modes of transmission, including both in vitro and in vivo studies. We also discuss the new intercellular communication pathway of the migrasome and microfluidic-based researches, which may provide a broader basis for studying intercellular communication mechanisms under various pathological and physiological conditions. Finally, we highlight the challenges and future research directions of intercellular transmission in the context of neurodegenerative diseases, laying a foundation for potential pathological analysis of the diseases.