[Discussion on the relationship between pathological changes of sciatic nerve and Sarm1 protein expression in rats with n-hexane poisoning].

Objective: To explore the potential evidence of active peripheral nerve necrosis when n-hexane produces toxic effects on peripheral nerves. Methods: In May 2023, 36 SPF grade SD male rats with a body weight of 200-220 g were divided into 4 groups with 9 rats in each group and given normal saline and different doses of n-hexane (168, 675, 2 700 mg/kg) by gavage for 6 consecutive weeks (5 days/week). Three rats in each group were killed at the 2nd, 4th and 6th week, respectively. The spinal cord to sciatic nerve tissue was broken and the supernatant was extracted for SDS-PAGE protein isolation. The expression level of Sarm1 protein was analyzed with the ß-Actin color strip of internal reference protein by Western blot. The expression of Sarm1 protein was analyzed by the gray ratio of the two. At the 6th week, the sciatic nerve sections of the each group were observed by light microscope and electron microscope. Results: The number of axons was obviously reduced by light microscopy. According to electron microscope, myelin lesions were mainly local disintegration, deformation, and different thickness. The deformation of axonal surface became smaller. The axons in the nerve bundle membrane showed degeneration and reduction. The gray ratio of Sarm1 protein and internal reference protein bands in each group had no significant change at the second week of exposure, and the ratio of SARM1 protein to internal reference protein bands was 1.47 in the high dose group at the fourth week, and 1.51 and 1.89 in the middle and high dose group at the sixth week, respectively. Conclusion: Waller's degeneration was observed in sciatic neuropathologic manifestations of n-hexane-poisoned rats, and the expression level of Sarm1 protein increased.

Excitable Rho dynamics control cell shape and motility by sequentially activating ERM proteins and actomyosin contractility.

Migration of endothelial and many other cells requires spatiotemporal regulation of protrusive and contractile cytoskeletal rearrangements that drive local cell shape changes. Unexpectedly, the small GTPase Rho, a crucial regulator of cell movement, has been reported to be active in both local cell protrusions and retractions, raising the question of how Rho activity can coordinate cell migration. Here, we show that Rho activity is absent in local protrusions and active during retractions. During retractions, Rho rapidly activated ezrin-radixin-moesin proteins (ERMs) to increase actin-membrane attachment, and, with a delay, nonmuscle myosin 2 (NM2). Rho activity was excitable, with NM2 acting as a slow negative feedback regulator. Strikingly, inhibition of SLK/LOK kinases, through which Rho activates ERMs, caused elongated cell morphologies, impaired Rho-induced cell contractions, and reverted Rho-induced blebbing. Together, our study demonstrates that Rho activity drives retractions by sequentially enhancing ERM-mediated actin-membrane attachment for force transmission and NM2-dependent contractility.

Autoinhibition and relief mechanisms for MICAL monooxygenases in F-actin disassembly.

MICAL proteins represent a unique family of actin regulators crucial for synapse development, membrane trafficking, and cytokinesis. Unlike classical actin regulators, MICALs catalyze the oxidation of specific residues within actin filaments to induce robust filament disassembly. The potent activity of MICALs requires tight control to prevent extensive damage to actin cytoskeleton. However, the molecular mechanism governing MICALs' activity regulation remains elusive. Here, we report the cryo-EM structure of MICAL1 in the autoinhibited state, unveiling a head-to-tail interaction that allosterically blocks enzymatic activity. The structure also reveals the assembly of C-terminal domains via a tripartite interdomain interaction, stabilizing the inhibitory conformation of the RBD. Our structural, biochemical, and cellular analyses elucidate a multi-step mechanism to relieve MICAL1 autoinhibition in response to the dual-binding of two Rab effectors, revealing its intricate activity regulation mechanisms. Furthermore, our mutagenesis study of MICAL3 suggests the conserved autoinhibition and relief mechanisms among MICALs.

Proteomic Analysis Reveals Physiological Activities of Aß Peptide for Alzheimer's Disease.

With the rapid progress in deciphering the pathogenesis of Alzheimer's disease (AD), it has been widely accepted that the accumulation of misfolded amyloid ß (Aß) in the brain could cause the neurodegeneration in AD. Although much evidence demonstrates the neurotoxicity of Aß, the role of Aß in the nervous system are complex. However, more comprehensive studies are needed to understand the physiological effect of Aß40 monomers in depth. To explore the physiological mechanism of Aß, we employed mass spectrometry to investigate the altered proteomic events induced by a lower submicromolar concentration of Aß. Human neuroblastoma SH-SY5Y cells were exposed to five different concentrations of Aß1-40 monomers and collected at four time points. The proteomic analysis revealed the time-course behavior of proteins involved in biological processes, such as RNA splicing, nuclear transport and protein localization. Further biological studies indicated that Aß40 monomers may activate PI3K/AKT signaling to regulate p-Tau, Ezrin and MAP2. These three proteins are associated with dendritic morphogenesis, neuronal polarity, synaptogenesis, axon establishment and axon elongation. Moreover, Aß40 monomers may regulate their physiological forms by inhibiting the expression of BACE1 and APP via activation of the ERK1/2 pathway. A comprehensive exploration of pathological and physiological mechanisms of Aß is beneficial for exploring novel treatment.

Cyclase-associated protein (CAP) inhibits inverted formin 2 (INF2) to induce dendritic spine maturation.

The morphology of dendritic spines, the postsynaptic compartment of most excitatory synapses, decisively modulates the function of neuronal circuits as also evident from human brain disorders associated with altered spine density or morphology. Actin filaments (F-actin) form the backbone of spines, and a number of actin-binding proteins (ABP) have been implicated in shaping the cytoskeleton in mature spines. Instead, only little is known about the mechanisms that control the reorganization from unbranched F-actin of immature spines to the complex, highly branched cytoskeleton of mature spines. Here, we demonstrate impaired spine maturation in hippocampal neurons upon genetic inactivation of cyclase-associated protein 1 (CAP1) and CAP2, but not of CAP1 or CAP2 alone. We found a similar spine maturation defect upon overactivation of inverted formin 2 (INF2), a nucleator of unbranched F-actin with hitherto unknown synaptic function. While INF2 overactivation failed in altering spine density or morphology in CAP-deficient neurons, INF2 inactivation largely rescued their spine defects. From our data we conclude that CAPs inhibit INF2 to induce spine maturation. Since we previously showed that CAPs promote cofilin1-mediated cytoskeletal remodeling in mature spines, we identified them as a molecular switch that control transition from filopodia-like to mature spines.

miR-143-3p modulates depressive-like behaviors via Lasp1 in the mouse ventral hippocampus.

Depression is a prevalent and intricate mental disorder. The involvement of small RNA molecules, such as microRNAs in the pathogenesis and neuronal mechanisms underlying the depression have been documented. Previous studies have demonstrated the involvement of microRNA-143-3p (miR-143-3p) in the process of fear memory and pathogenesis of ischemia; however, the relationship between miR-143-3p and depression remains poorly understood. Here we utilized two kinds of mouse models to investigate the role of miR-143-3p in the pathogenesis of depression. Our findings reveal that the expression of miR-143-3p is upregulated in the ventral hippocampus (VH) of mice subjected to chronic restraint stress (CRS) or acute Lipopolysaccharide (LPS) treatment. Inhibiting the expression of miR-143-3p in the VH effectively alleviates depressive-like behaviors in CRS and LPS-treated mice. Furthermore, we identify Lasp1 as one of the downstream target genes regulated by miR-143-3p. The miR-143-3p/Lasp1 axis primarily affects the occurrence of depressive-like behaviors in mice by modulating synapse numbers in the VH. Finally, miR-143-3p/Lasp1-induced F-actin change is responsible for the synaptic number variations in the VH. In conclusion, this study enhances our understanding of microRNA-mediated depression pathogenesis and provides novel prospects for developing therapeutic approaches for this intractable mood disorder.

AUTS2 disruption causes neuronal differentiation defects in human cerebral organoids through hyperactivation of the WNT/ß-catenin pathway.

Individuals with the Autism Susceptibility Candidate 2 (AUTS2) gene disruptions exhibit symptoms such as intellectual disability, microcephaly, growth retardation, and distinct skeletal and facial differences. The role of AUTS2 in neurodevelopment has been investigated using animal and embryonic stem cell models. However, the precise molecular mechanisms of how AUTS2 influences neurodevelopment, particularly in humans, are not thoroughly understood. Our study employed a 3D human cerebral organoid culture system, in combination with genetic, genomic, cellular, and molecular approaches, to investigate how AUTS2 impacts neurodevelopment through cellular signaling pathways. We used CRISPR/Cas9 technology to create AUTS2-deficient human embryonic stem cells and then generated cerebral organoids with these cells. Our transcriptomic analyses revealed that the absence of AUTS2 in cerebral organoids reduces the populations of cells committed to the neuronal lineage, resulting in an overabundance of cells with a transcription profile resembling that of choroid plexus (ChP) cells. Intriguingly, we found that AUTS2 negatively regulates the WNT/ß-catenin signaling pathway, evidenced by its overactivation in AUTS2-deficient cerebral organoids and in luciferase reporter cells lacking AUTS2. Importantly, treating the AUTS2-deficient cerebral organoids with a WNT inhibitor reversed the overexpression of ChP genes and increased the downregulated neuronal gene expression. This study offers new insights into the role of AUTS2 in neurodevelopment and suggests potential targeted therapies for neurodevelopmental disorders.

Arc and BDNF mediated effects of hippocampal astrocytic glutamate uptake blockade on spatial memory stages.

Glutamate is involved in fundamental functions, including neuronal plasticity and memory. Astrocytes are integral elements involved in synaptic function, and the GLT-1 transporter possesses a critical role in glutamate uptake. Here, we study the role of GLT-1, specifically located in astrocytes, in the consolidation, expression, reconsolidation and persistence of spatial object recognition memory in rats. Administration of dihydrokainic acid (DHK), a selective GLT-1 inhibitor, into the dorsal hippocampus around a weak training which only induces short-term memory, promotes long-term memory formation. This promotion is prevented by hippocampal administration of protein-synthesis translation inhibitor, blockade of Activity-regulated cytoskeleton-associated protein (Arc) translation or Brain-Derived Neurotrophic Factor (BDNF) action, which are plasticity related proteins necessary for memory consolidation. However, DHK around a strong training, which induces long-term memory, does not affect memory consolidation. Administration of DHK before the test session impairs the expression of long-term memory, and this effect is dependent of Arc translation. Furthermore, DHK impairs reconsolidation if applied before a reactivation session, and this effect is independent of Arc translation. These findings reveal specific consequences on spatial memory stages developed under hippocampal GLT-1 blockade, shedding light on the intricate molecular mechanisms, governed in part for the action of glia.

Coordination of force-generating actin-based modules stabilizes and remodels membranes in vivo.

Membrane remodeling drives a broad spectrum of cellular functions, and it is regulated through mechanical forces exerted on the membrane by cytoplasmic complexes. Here, we investigate how actin filaments dynamically tune their structure to control the active transfer of membranes between cellular compartments with distinct compositions and biophysical properties. Using intravital subcellular microscopy in live rodents we show that a lattice composed of linear filaments stabilizes the granule membrane after fusion with the plasma membrane and a network of branched filaments linked to the membranes by Ezrin, a regulator of membrane tension, initiates and drives to completion the integration step. Our results highlight how the actin cytoskeleton tunes its structure to adapt to dynamic changes in the biophysical properties of membranes.

The mGluR5-mediated Arc activation protects against experimental traumatic brain injury in rats.

INTRODUCTION: Traumatic brain injury (TBI) is a complex pathophysiological process, and increasing attention has been paid to the important role of post-synaptic density (PSD) proteins, such as glutamate receptors. Our previous study showed that a PSD protein Arc/Arg3.1 (Arc) regulates endoplasmic reticulum (ER) stress and neuronal necroptosis in traumatic injury in vitro. AIM: In this study, we investigated the expression, regulation and biological function of Arc in both in vivo and in vitro experimental TBI models. RESULTS: Traumatic neuronal injury (TNI) induced a temporal upregulation of Arc in cortical neurons, while TBI resulted in sustained increase in Arc expression up to 24 h in rats. The increased expression of Arc was mediated by the activity of metabotropic glutamate receptor 5 (mGluR5), but not dependent on the intracellular calcium (Ca2+) release. By using inhibitors and antagonists, we found that TNI regulates Arc expression via Gq protein and protein turnover. In addition, overexpression of Arc protects against TBI-induced neuronal injury and motor dysfunction both in vivo and in vitro, whereas the long-term cognitive function was not altered. To determine the role of Arc in mGluR5-induced protection, lentivirus-mediated short hairpin RNA (shRNA) transfection was performed to knockdown Arc expression. The mGluR5 agonist (RS)-2-chloro-5-hydroxyphenylglycine (CHPG)-induced protection against TBI was partially prevented by Arc knockdown. Furthermore, the CHPG-induced attenuation of Ca2+ influx after TNI was dependent on Arc activation and followed regulation of AMPAR subunits. The results of Co-IP and Ca2+ imaging showed that the Arc-Homer1 interaction contributes to the CHPG-induced regulation of intracellular Ca2+ release. CONCLUSION: In summary, the present data indicate that the mGluR5-mediated Arc activation is a protective mechanism that attenuates neurotoxicity following TBI through the regulation of intracellular Ca2+ hemostasis. The AMPAR-associated Ca2+ influx and ER Ca2+ release induced by Homer1-IP3R pathway might be involved in this protection.

Mutations in linker-2 of KLF1 impair expression of membrane transporters and cytoskeletal proteins causing hemolysis.

The SP/KLF family of transcription factors harbour three C-terminal C2H2 zinc fingers interspersed by two linkers which confers DNA-binding to a 9-10 bp motif. Mutations in KLF1, the founding member of the family, are common. Missense mutations in linker two result in a mild phenotype. However, when co-inherited with loss-of-function mutations, they result in severe non-spherocytic hemolytic anemia. We generate a mouse model of this disease by crossing Klf1+/- mice with Klf1H350R/+ mice that harbour a missense mutation in linker-2. Klf1H350R/- mice exhibit severe hemolysis without thalassemia. RNA-seq demonstrate loss of expression of genes encoding transmembrane and cytoskeletal proteins, but not globins. ChIP-seq show no change in DNA-binding specificity, but a global reduction in affinity, which is confirmed using recombinant proteins and in vitro binding assays. This study provides new insights into how linker mutations in zinc finger transcription factors result in different phenotypes to those caused by loss-of-function mutations.

The activity-regulated cytoskeleton-associated protein (Arc) functions in a cell type- and sex-specific manner in the adult nucleus accumbens to regulate non-contingent cocaine behaviors.

Repeated cocaine use produces adaptations in brain function that contribute to long-lasting behaviors associated with cocaine use disorder (CUD). In rodents, the activity-regulated cytoskeleton-associated protein (Arc) can regulate glutamatergic synaptic transmission, and cocaine regulates Arc expression and subcellular localization in multiple brain regions, including the nucleus accumbens (NAc)-a brain region linked to CUD-related behavior. We show here that repeated, non-contingent cocaine administration in global Arc KO male mice produced a dramatic hypersensitization of cocaine locomotor responses and drug experience-dependent sensitization of conditioned place preference (CPP). In contrast to the global Arc KO mice, viral-mediated reduction of Arc in the adult male, but not female, NAc (shArcNAc) reduced both CPP and cocaine-induced locomotor activity, but without altering basal miniature or evoked glutamatergic synaptic transmission. Interestingly, cell type-specific knockdown of Arc in D1 dopamine receptor-expressing NAc neurons reduced cocaine-induced locomotor sensitization, but not cocaine CPP; whereas, Arc knockdown in D2 dopamine receptor-expressing NAc neurons reduced cocaine CPP, but not cocaine-induced locomotion. Taken together, our findings reveal that global, developmental loss of Arc produces hypersensitized cocaine responses; however, these effects cannot be explained by Arc's function in the adult mouse NAc since Arc is required in a cell type- and sex-specific manner to support cocaine-context associations and locomotor responses.

Phosphatidylinositol-3-phosphate mediates Arc capsid secretion through the multivesicular body pathway.

Activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) is an immediate early gene that plays a vital role in learning and memory. Arc protein has structural and functional properties similar to viral Group-specific antigen (Gag) protein and mediates the intercellular RNA transfer through virus-like capsids. However, the regulators and secretion pathway through which Arc capsids maneuver cargos are unclear. Here, we identified that phosphatidylinositol-3-phosphate (PI3P) mediates Arc capsid assembly and secretion through the endosomal-multivesicular body (MVB) pathway. Indeed, reconstituted Arc protein preferably binds to PI3P. In HEK293T cells, Arc forms puncta that colocalize with FYVE, an endosomal PI3P marker, as well as Rab5 and CD63, early endosomal and MVB markers, respectively. Superresolution imaging resolves Arc accumulates within the intraluminal vesicles of MVB. CRISPR double knockout of RalA and RalB, crucial GTPases for MVB biogenesis and exocytosis, severely reduces the Arc-mediated RNA transfer efficiency. RalA/B double knockdown in cultured rat cortical neurons increases the percentage of mature dendritic spines. Intake of extracellular vesicles purified from Arc-expressing wild-type, but not RalA/B double knockdown, cells in mouse cortical neurons reduces their surface GlutA1 levels. These results suggest that unlike the HIV Gag, whose membrane targeting requires interaction with plasma-membrane-specific phosphatidyl inositol (4,5) bisphosphate (PI(4,5)P2), the assembly of Arc capsids is mediated by PI3P at endocytic membranes. Understanding Arc's secretion pathway helps gain insights into its role in intercellular cargo transfer and highlights the commonality and distinction of trafficking mechanisms between structurally resembled capsid proteins.

Endogenous capsid-forming protein ARC for self-assembling nanoparticle vaccines.

The application of nanoscale scaffolds has become a promising strategy in vaccine design, with protein-based nanoparticles offering desirable avenues for the biocompatible and efficient delivery of antigens. Here, we presented a novel endogenous capsid-forming protein, activated-regulated cytoskeleton-associated protein (ARC), which could be engineered through the plug-and-play strategy (SpyCatcher3/SpyTag3) for multivalent display of antigens. Combined with the self-assembly capacity and flexible modularity of ARC, ARC-based vaccines elicited robust immune responses against Mpox or SARS-CoV-2, comparable to those induced by ferritin-based vaccines. Additionally, ARC-based nanoparticles functioned as immunostimulants, efficiently stimulating dendritic cells and facilitating germinal center responses. Even without adjuvants, ARC-based vaccines generated protective immune responses in a lethal challenge model. Hence, this study showed the feasibility of ARC as a novel protein-based nanocarrier for multivalent surface display of pathogenic antigens and demonstrated the potential of exploiting recombinant mammalian retrovirus-like protein as a delivery vehicle for bioactive molecules.

RNA-binding protein GIGYF2 orchestrates hepatic insulin resistance through STAU1/PTEN-mediated disruption of the PI3K/AKT signaling cascade.

BACKGROUND: Obesity is well-established as a significant contributor to the development of insulin resistance (IR) and diabetes, partially due to elevated plasma saturated free fatty acids like palmitic acid (PA). Grb10-interacting GYF Protein 2 (GIGYF2), an RNA-binding protein, is widely expressed in various tissues including the liver, and has been implicated in diabetes-induced cognitive impairment. Whereas, its role in obesity-related IR remains uninvestigated. METHODS: In this study, we employed palmitic acid (PA) exposure to establish an in vitro IR model in the human liver cancer cell line HepG2 with high-dose chronic PA treatment. The cells were stained with fluorescent dye 2-NBDG to evaluate cell glucose uptake. The mRNA expression levels of genes were determined by real-time qRT-PCR (RT-qPCR). Western blotting was employed to examine the protein expression levels. The RNA immunoprecipitation (RIP) was used to investigate the binding between protein and mRNA. Lentivirus-mediated gene knockdown and overexpression were employed for gene manipulation. In mice, an IR model induced by a high-fat diet (HFD) was established to validate the role and action mechanisms of GIGYF2 in the modulation of HFD-induced IR in vivo. RESULTS: In hepatocytes, high levels of PA exposure strongly trigger the occurrence of hepatic IR evidenced by reduced glucose uptake and elevated extracellular glucose content, which is remarkably accompanied by up-regulation of GIGYF2. Silencing GIGYF2 ameliorated PA-induced IR and enhanced glucose uptake. Conversely, GIGYF2 overexpression promoted IR, PTEN upregulation, and AKT inactivation. Additionally, PA-induced hepatic IR caused a notable increase in STAU1, which was prevented by depleting GIGYF2. Notably, silencing STAU1 prevented GIGYF2-induced PTEN upregulation, PI3K/AKT pathway inactivation, and IR. STAU1 was found to stabilize PTEN mRNA by binding to its 3'UTR. In liver cells, tocopherol treatment inhibits GIGYF2 expression and mitigates PA-induced IR. In the in vivo mice model, GIGYF2 knockdown and tocopherol administration alleviate high-fat diet (HFD)-induced glucose intolerance and IR, along with the suppression of STAU1/PTEN and restoration of PI3K/AKT signaling. CONCLUSIONS: Our study discloses that GIGYF2 mediates obesity-related IR by disrupting the PI3K/AKT signaling axis through the up-regulation of STAU1/PTEN. Targeting GIGYF2 may offer a potential strategy for treating obesity-related metabolic diseases, including type 2 diabetes.

Pterostilbene exerts anti-lung squamous cell carcinoma function by suppressing the level of KANK3.

Early detection of lung squamous cell carcinoma (LUSC) has a significant impact on clinical outcomes, and pterostilbene (PT) is a natural compound with promising anti-oncogenic activities. This study aimed to identify potential LUSC biomarkers through a series of bioinformatic analyses and clinical verification and explored the interaction between PT and selected biomarkers during the treatment of LUSC. The analysis of the expression profile of the clinical samples of LUSC was performed to identify dysexpressed genes (DEGs) and validated by IHC. The role of KANK3 in the anti-LUSC effects of PT was assessed with a series of in vitro and in vivo assays. 4335 DEGs were identified, including 1851 upregulated genes and 2484 downregulated genes. Survival analysis showed that KANK3 was significantly higher in patients with LUSC with an advanced tumor stage. In in vitro assays, PT suppressed cell viability, induced apoptosis, and inhibited migration and invasion in LUSC cell lines, which was associated with downregulation of KANK3. After the reinduction of the KANK3 level in LUSC cells, the anti-LUSC function of PT was impaired. In mice model, reinduction of KANK3 increased tumor growth and metastasis even under the treatment of PT. The findings outlined in the current study indicated that PT exerted anti-LUSC function in a KANK3 inhibition-dependent manner.

Building the Bacterial Divisome at the Septum.

Across living organisms, division is necessary for cell survival and passing heritable information to the next generation. For this reason, cell division is highly conserved among eukaryotes and prokaryotes. Among the most highly conserved cell division proteins in eukaryotes are tubulin and actin. Tubulin polymerizes to form microtubules, which assemble into cytoskeletal structures in eukaryotes, such as the mitotic spindle that pulls chromatids apart during mitosis. Actin polymerizes to form a morphological framework for the eukaryotic cell, or cytoskeleton, that undergoes reorganization during mitosis. In prokaryotes, two of the most highly conserved cell division proteins are the tubulin homolog FtsZ and the actin homolog FtsA. In this chapter, the functions of the essential bacterial cell division proteins FtsZ and FtsA and their roles in assembly of the divisome at the septum, the site of cell division, will be discussed. In most bacteria, including Escherichia coli, the tubulin homolog FtsZ polymerizes at midcell, and this step is crucial for recruitment of many other proteins to the division site. For this reason, both FtsZ abundance and polymerization are tightly regulated by a variety of proteins. The actin-like FtsA protein polymerizes and tethers FtsZ polymers to the cytoplasmic membrane. Additionally, FtsA interacts with later stage cell division proteins, which are essential for division and for building the new cell wall at the septum. Recent studies have investigated how actin-like polymerization of FtsA on the lipid membrane may impact division, and we will discuss this and other ways that division in bacteria is regulated through FtsZ and FtsA.

Molecular dynamics simulations reveal differences in the conformational stability of FtsZs derived from Staphylococcus aureus and Bacillus subtilis.

FtsZ is highly conserved among bacteria and plays an essential role in bacterial cell division. The tense conformation of FtsZ bound to GTP assembles into a straight filament via head-to-tail associations, and then the upper subunit of FtsZ hydrolyzes GTP bound to the lower FtsZ subunit. The subunit with GDP bound disassembles accompanied by a conformational change in the subunit from the tense to relaxed conformation. Although crystal structures of FtsZ derived from several bacterial species have been determined, the conformational change from the relaxed to tense conformation has only been observed in Staphylococcus aureus FtsZ (SaFtsZ). Recent cryo-electron microscopy analyses revealed the three-dimensional reconstruction of the protofilament, in which tense molecules assemble via head-to-tail associations. However, the lower resolution of the protofilament suggested that the flexibility of the FtsZ protomers between the relaxed and tense conformations caused them to form in less-strict alignments. Furthermore, this flexibility may also prevent FtsZs other than SaFtsZ from crystalizing in the tense conformation, suggesting that the flexibility of bacterial FtsZs differs. In this study, molecular dynamics simulations were performed using SaFtsZ and Bacillus subtilis FtsZ in several situations, which suggested that different features of the FtsZs affect their conformational stability.

Pyridine-based small molecule inhibitors of SARM1 alleviate cell death caused by NADase activity.

Our investigation has unveiled a series of pyridine-based SARM1 inhibitors, with the lead compound TH-408 exhibiting remarkable potency, achieving an IC50 value of 0.46 µM. This exceptional inhibitory effect significantly curtailed SARM1-mediated cell death across diverse biological models. This finding highlights the promising therapeutic potential for neurodegenerative disorders by disrupting SARM1 activation and advances our understanding of molecular interventions in these complex disorders, including the regulation of NAD+ metabolism.