Inhibition Of ATP Synthesis Research Articles

Contribution of telacebec to novel drug regimens in a murine tuberculosis model.

The clinical efficacy of combination drug regimens containing the first-generation diarylquinoline (DARQ) bedaquiline in the treatment of multidrug-resistant tuberculosis has validated ATP synthesis as a vulnerable pathway in Mycobacterium tuberculosis. New DARQs in clinical development may be even more effective than bedaquiline, including against emerging bedaquiline-resistant strains. Telacebec (T) is a novel cytochrome bc1:aa3 oxidase inhibitor that also inhibits ATP synthesis. Based on its demonstrated efficacy as a monotherapy in mice and in a phase 2a clinical trial, we tested the contribution of T to novel combination therapies against two strains of M. tuberculosis (H37Rv and HN878) in an established BALB/c mouse model of tuberculosis in an effort to find more effective regimens. Overall, T was more effective in regimens against the HN878 strain than against the H37Rv strain, a finding supported by the greater vulnerability of the former strain to T and to genetic depletion of QcrB. Against both strains, combinations of a DARQ, clofazimine, and T were highly bactericidal. However, only against HN878 did T contribute synergistically, whereas an antagonistic effect was observed against H37Rv. These results demonstrate the therapeutic potential of T and highlight how differences in the susceptibility of M. tuberculosis strains could lead to different conclusions about a drug's potential contribution to novel drug regimens.CLINICAL TRIALSThis study is registered with Clinicaltrials.gov as NCT04890535 and NCT06058299.

Dermoscopic Changes of a Cutaneous Leishmaniasis Treated with Intralesional Pentavalent Antimonials: A Case Report

Leishmaniasis is a group of parasitic diseases caused by flagellated protozoa of the genus Leishmania with tropism for cells of the reticuloendothelial system, transmitted to many mammals by the bite of the sandfly. They can be visceral, cutaneous or mucocutaneous and represent a public health problem in countries where they are endemic. The diagnosis of cutaneous leishmaniasis is based on epidemiologic, clinical and dermoscopic evidence, with diagnostic certainty established by parasitologic examination, histology or PCR. Dermoscopic findings include erythema, starburst appearance, hyperkeratosis, central ulceration, yellow tears, salmon-colored ovoid structures, glomerular, linear, irregular, hairpin or arborizing vessels, and hypochromic perilesional halo. Pentavalent antimonials are used therapeutically in leishmaniasis, inhibiting ATP synthesis, fatty acids and glycolic oxidation, with immunostimulating and immunoregulatory properties. Our case is a cutaneous leishmaniasis treated with pentavalent antimonials, in which we monitored the dermoscopic appearance of the lesions as the sessions progressed. The salmon-colored ovoid structures were the first to disappear, followed by hyperkeratosis and erosion, then the initially polymorphic vascularization became monomorphic. Yellow tears and erythema were the last structures to disappear. Our article shows that the disappearance of certain structures and the appearance of others can be a good indicator of how close to healing the lesion is.

Photocatalytic therapy via photoinduced redox imbalance in biological system

Redox balance is essential for sustaining normal physiological metabolic activities of life. In this study, we present a photocatalytic system to perturb the balance of NADH/NAD+ in oxygen-free conditions, achieving photocatalytic therapy to cure anaerobic bacterial infected periodontitis. Under light irradiation, the catalyst TBSMSPy+ can bind bacterial DNA and initiate the generation of radical species through a multi-step electron transfer process. It catalyzes the conversion from NADH to NAD+ (the turnover frequency up to 60.7 min−1), inhibits ATP synthesis, disrupts the energy supply required for DNA replication, and successfully accomplishes photocatalytic sterilization in an oxygen-free environment. The catalyst participates in the redox reaction, interfering with the balance of NADH/NAD+ contents under irradiation, so we termed this action as photoinduced redox imbalance. Additionally, animal experiments in male rats also validate that the TBSMSPy+ could effectively catalyze the NADH oxidation, suppress metabolism and stimulate osteogenesis. Our research substantiates the concept of photoinduced redox imbalance and the application of photocatalytic therapy, further advocating the development of such catalyst based on photoinduced redox imbalance strategy for oxygen-free phototherapy.

Borosilicate bioactive glass synergizing low-dose antibiotic loaded implants to combat bacteria through ATP disruption and oxidative stress to sequentially achieve osseointegration

Bone infection is a catastrophe in clinical orthopedics. Despite being the standard therapy for osteomyelitis, antibiotic-loaded polymethyl methacrylate (PMMA) cement has low efficiency against bacteria in biofilms. Furthermore, high-dose antibiotic-loaded implants carry risks of bacterial resistance, tissue toxicity, and impairment of local tissue healing. By incorporating borosilicate bioactive glass (BSG) into low-dose gentamicin sulfate (GS)-loaded PMMA cement, an intelligent strategy that synergistically eradicates bacteria and sequentially promotes osseointegration, was devised. Results showed that BSG did not compromises the handling properties of the cement, but actually endowed it with an ionic and alkaline microenvironment, thereby damaging the integrity of bacterial cell walls and membranes, inhibiting ATP synthesis by disrupting the respiratory chain in cell membranes and glycogen metabolism, and elevating reactive oxygen species (ROS) levels by weakening antioxidant components (peroxisomes and carotenoids). These antibacterial characteristics of BSG synergistically reinforced the effectiveness of GS, which was far below the actual clinical dosage, achieving efficient bacterial killing and biofilm clearance by binding to the 30S subunit of ribosomes. Furthermore, the released GS and the ionic and alkaline microenvironment from the implants fostered the osteogenic activity of hBMSCs in vitro and coordinately enhanced osseointegration in vivo. Collectively, this study underscores that BSG incorporation offers a promising strategy for reducing antibiotic dosage while simultaneously enhancing the antibacterial activity and osteogenesis of implants. This approach holds potential for resolving the conflict between bacterial resistance and bone infection.

Safe, simple and multifunctional hydroxyapatite nanoparticles for efficient overcoming of tumor multidrug resistance

Multidrug resistance (MDR) of cancer is the most common obstacle to chemotherapy. Many complex multifunctional nanoparticles have been developed for combination of two or more therapeutics to overcome MDR. Unlike these sophisticated nanoparticles, hydroxyapatite nanoparticles (HAPNs) were found to be able to inhibit cell proliferation of various human cancer cells. Herein, with different MDR cells and chemotherapeutic drugs, we tested whether HAPNs can be widely applied in fighting cancer drug resistance. Rod-shaped HAPNs were synthesized by the aqueous precipitation and then successfully loaded with paclitaxel (PTX) and doxorubicin (DOX) by physical adsorption to obtain pH-responsive drug-loaded nanoparticles, PHAPNs and DHAPNs, respectively. Plain HAPNs exhibited selective cytotoxicity to drug-resistant breast cancer cells MCF-7/ADR, lung cancer cells H69AR and A549/PTX, while spared normal human liver cells L-02. HAPN treatment led to an increase in the apoptosis ratio, a decrease in cell viability and a sustained increase in intracellular calcium ion level in MDR cells. Furthermore, HAPNs facilitated the delivery and accumulation of both drugs, thereby improving the DOX-induced DNA damage in H69AR cells, as well as the acetylation of α-tubulin and cell cycle arrest led by PTX in MCF-7/ADR and A549/PTX cells. Drug-loaded HAPNs greatly enhanced mitochondrial damage, inhibited ATP synthesis and efflux pump activity, and triggered both the intrinsic and extrinsic apoptosis induced by HAPNs or drugs alone. HAPNs acted synergistically with DOX and PTX, resulting in a >6-fold reduction in the IC50 compared with free drugs for these MDR cells. Notably, PHAPNs successfully suppressed the tumor growth in A549/PTX xenograft mice and exhibited excellent biocompatibility in vivo. These findings demonstrated that HAPNs may be widely utilized to reverse the resistance of various drug-resistant cells, providing a simple but practical approach to overcome MDR of cancer.

A novel cathelicidin TS-CATH derived from Thamnophis sirtalis combats drug-resistant gram-negative bacteria in vitro and in vivo

Antimicrobial peptides are promising therapeutic agents for treating drug-resistant bacterial disease due to their broad-spectrum antimicrobial activity and decreased susceptibility to evolutionary resistance. In this study, three novel cathelicidin antimicrobial peptides were identified from Thamnophis sirtalis, Balaenoptera musculus, and Lipotes vexillifer by protein database mining and sequence alignment and were subsequently named TS-CATH, BM-CATH, and LV-CATH, respectively. All three peptides exhibited satisfactory antibacterial activity and broad antibacterial spectra against clinically isolated E. coli, P. aeruginosa, K. pneumoniae, and A. baumannii in vitro. Among them, TS-CATH displayed the best antimicrobial/bactericidal activity, with a rapid elimination efficiency against the tested drug-resistant gram-negative bacteria within 20 min, and exhibited the lowest cytotoxicity toward mammalian cells. Furthermore, TS-CATH effectively enhanced the survival rate of mice with ceftazidime-resistant E. coli bacteremia and promoted wound healing in meropenem-resistant P. aeruginosa infection. These results were achieved through the eradication of bacterial growth in target organs and wounds, further inhibiting the systemic dissemination of bacteria and the inflammatory response. TS-CATH exhibited direct antimicrobial activity by damaging the inner and outer membranes, resulting in leakage of the bacterial contents at super-MICs. Moreover, TS-CATH disrupted the bacterial respiratory chain, which inhibited ATP synthesis and induced ROS formation, significantly contributing to its antibacterial efficacy at sub-MICs. Overall, TS-CATH has potential for use as an antibacterial agent.

Bactericidal and sterilizing activity of sudapyridine-clofazimine-TB47 combined with linezolid or pyrazinamide in a murine model of tuberculosis.

As an obligate aerobe, Mycobacterium tuberculosis relies on its branched electron transport chain (ETC) for energy production through oxidative phosphorylation. Regimens targeting ETC exhibit promising potential to enhance bactericidal activity against M. tuberculosis and hold the prospect of shortening treatment duration. Our previous research demonstrated that the bacteriostatic drug candidate TB47 (T) inhibited the growth of M. tuberculosis by targeting the cytochrome bc1 complex and exhibited synergistic activity with clofazimine (C). Here, we found synergistic activities between C and sudapyridine (S), a structural analog of bedaquiline (B). S has shown similar anti-tuberculosis efficacy and may share a mechanism of action with B, which inhibits ATP synthesis and the energy metabolism of bacteria. We evaluated the efficacy of SCT in combination with linezolid (L) or pyrazinamide (Z) using a well-established murine model of tuberculosis. Compared to the BPa(pretomanid)L regimen, SCT and SCTL demonstrated similar bactericidal and sterilizing activities. There was no significant difference in activity between SCT and SCTL. In contrast, SCZ and SCTZ showed much higher activities, with none of the 15 mice experiencing relapse after 2 months of treatment with either SCZ or SCTZ. However, T did not contribute to the activity of the SCZ. Our findings emphasize the efficacy and the potential clinical significance of combination therapy with ETC inhibitors. Additionally, cross-resistance exists not only between S and B but also between S/B and C. This is supported by our findings, as spontaneous S-resistant mutants exhibited mutations in Rv0678, which are associated with cross-resistance to B and C.

Mechanisms of ingested polystyrene micro-nanoplastics (MNPs) uptake and translocation in an in vitro tri-culture small intestinal epithelium

Micro and nanoplastics (MNPs) are now ubiquitous contaminants of food and water. Many cellular and animal studies have shown that ingested MNPs can breach the intestinal barrier to reach the circulation. To date however, the cellular mechanisms involved in intestinal absorption of MNPs have not been investigated with physiologically relevant models, and thus remain unknown. We employed in vitro simulated digestion, a tri-culture small intestinal epithelium model, and a panel of inhibitors to assess the contributions of the possible mechanisms to absorption of 26 nm carboxylated polystyrene (PS26C) MNPs. Inhibition of ATP synthesis reduced translocation by only 35 %, suggesting uptake by both active endocytic pathways and passive diffusion. Translocation was also decreased by inhibition of dynamin and clathrin, suggesting involvement of clathrin mediated endocytosis (CME) and fast endophilin-mediated endocytosis (FEME). Inhibition of actin polymerization also significantly reduced translocation, suggesting involvement of macropinocytosis or phagocytosis. However, inhibition of the Na+-H+ exchanger had no effect on translocation, thus ruling out macropinocytosis. Together these results suggest uptake by passive diffusion as well as by active phagocytosis, CME, and FEME pathways. Further studies are needed to assess uptake mechanisms for other environmentally relevant MNPs as a function of polymer, surface chemistry, and size.

Calcium-induced upregulation of energy metabolism heats neurons during neural activity

Cellular temperature affects every biochemical reaction, underscoring its critical role in cellular functions. In neurons, temperature not only modulates neurotransmission but is also a key determinant of neurodegenerative diseases. Considering that the brain consumes a disproportionately high amount of energy relative to its weight, neural circuits likely generate a lot of heat, which can increase cytosolic temperature. However, the changes in temperature within neurons and the mechanisms of heat generation during neural excitation remain unclear. In this study, we achieved simultaneous imaging of Ca2+ and temperature using the genetically encoded indicators, B-GECO and B-gTEMP. We then compared the spatiotemporal distributions of Ca2+ responses and temperature. Following neural excitation induced by veratridine, an activator of the voltage-gated Na+ channel, we observed an approximately 2 °C increase in cytosolic temperature occurring 30 s after the Ca2+ response. The temperature elevation was observed in the non-nuclear region, while Ca2+ increased throughout the cell body. Moreover, this temperature increase was suppressed under Ca2+-free conditions and by inhibitors of ATP synthesis. These results indicate that Ca2+-induced upregulation of energy metabolism serves as the heat source during neural excitation.

Experimental evidence for Parthanatos-like mode of cell death of heat-damaged human skin fibroblasts in a cell culture-based in vitro burn model

The cellular mechanisms of burn conversion of heat damaged tissue are center of many studies. Even if the molecular mechanisms of heat-induced cell death are controversially discussed in the current literature, it is widely accepted that caspase-mediated apoptosis plays a central role. In the current study we wanted to develop further information on the nature of the mechanism of heat-induced cell death of fibroblasts in vitro. We found that heating of human fibroblast cultures (a 10 s rise from 37 °C to 67 °C followed by a 13 s cool down to 37 °C) resulted in the death of about 50% of the cells. However, the increase in cell death started with a delay, about one hour after exposure to heat, and reached the maximum after about five hours. The lack of clear evidence for an active involvement of effector caspase in the observed cell death mechanism and the lack of observation of the occurrence of hypodiploid nuclei contradict heat-induced cell death by caspase-mediated apoptosis. Moreover, a dominant heat-induced increase in PARP1 protein expression, which correlated with a time-delayed ATP synthesis inhibition, appearance of double-strand breaks and secondary necrosis, indicate a different type of cell death than apoptosis. Indeed, increased translocation of Apoptosis Inducing Factor (AIF) and Macrophage Migration Inhibitory Factor (MIF) into cell nuclei, which correlates with the mentioned enhanced PARP1 protein expression, indicate PARP1-induced, AIF-mediated and MIF-activated cell death. With regard to the molecular actors involved, the cellular processes and temporal sequences, the mode of cell death observed in our model is very similar to the cell death mechanism via Parthanatos described in the literature.

Cellular energy regulates mRNA degradation in a codon-specific manner

Codon optimality is a major determinant of mRNA translation and degradation rates. However, whether and through which mechanisms its effects are regulated remains poorly understood. Here we show that codon optimality associates with up to 2-fold change in mRNA stability variations between human tissues, and that its effect is attenuated in tissues with high energy metabolism and amplifies with age. Mathematical modeling and perturbation data through oxygen deprivation and ATP synthesis inhibition reveal that cellular energy variations non-uniformly alter the effect of codon usage. This new mode of codon effect regulation, independent of tRNA regulation, provides a fundamental mechanistic link between cellular energy metabolism and eukaryotic gene expression.

Enhanced photodynamic therapy efficacy of Ni-doped/oxygen vacancy double-defect Ni-ZnO@C photosensitizer in bacteria-infected wounds based on ROS damage and ATP synthesis inhibition

The use of zinc oxide (ZnO) photosensitizers (PSs)-mediated photodynamic therapy (PDT) against bacterial wound infections is greatly restricted by diminished photocatalytic efficiency caused by the rapid recombination of photogenerated electrons and holes. In this work, ZnO PSs with a Ni-doped/oxygen vacancy and a protective carbon shell were successfully synthesized by calcinating a Ni-doping zeolitic imidazolate framework-8 precursor. The double-defect structure and the carbon-based substrates significantly promoted the efficiency of photogenerated electron–hole pair separation, meanwhile, the 3 % Ni doping endows it with great photocatalytic performance as elucidated by photodegradation assays of methylene blue (MB) and density functional theory (DFT) calculations, reinforcing the generation of reactive oxygen species (ROS) by ZnO and showing obvious advantages in antibacterial properties. As the enhanced photogenerated electron transfer and the ROS damage underwent localized accumulation, the PSs disturbed the bacterial membrane integrity and caused bacterial ATP synthesis inhibition, further leading to bacterial lysis and promoting bacterial deaths. Additionally, the PSs showed outstanding efficacy in eradicating bacterial biofilms. Simultaneously, the significantly enhanced PDT antibacterial performance of the PSs in vivo could initiate wound tissue repair and trigger anti-inflammatory reactions by significantly regulating the expression levels of regeneration- and inflammation-related genes or proteins. Furthermore, the PSs consistently exhibited favorable compatibility both in vitro and in vivo. In summary, this study offers evidence of the remarkably efficient and biologically safe performance of Ni-ZnO@C PSs, with antibacterial properties advancing wound healing, both in controlled laboratory environments and living organisms, further underscoring their substantial potential for biomedical applications.

Selenite ameliorates the ATP hydrolysis of mitochondrial F1FO-ATPase by changing the redox state of thiol groups and impairs the ADP phosphorylation

Selenite as an inorganic form of selenium can affect the redox state of mitochondria by modifying the thiol groups of cysteines. The F1FO-ATPase has been identified as a mitochondrial target of this compound. Indeed, the bifunctional mechanism of ATP turnover of F1FO-ATPase was differently modified by selenite. The activity of ATP hydrolysis was stimulated, whereas the ADP phosphorylation was inhibited. We ascertain that a possible new protein adduct identified as seleno-dithiol (-S-Se-S-) mercaptoethanol-sensitive caused the activation of F-ATPase activity and the oxidation of free –SH groups in mitochondria. Conversely, the inhibition of ATP synthesis by selenite might be irreversible. The kinetic analysis of the activation mechanism was an uncompetitive mixed type with respect to the ATP substrate. Selenite bound more selectively to the F1FO-ATPase loaded with the substrate by preferentially forming a tertiary (enzyme-ATP-selenite) complex. Otherwise, the selenite was a competitive mixed-type activator with respect to the Mg2+ cofactor. Thus, selenite more specifically bound to the free enzyme forming the complex enzyme-selenite. However, even if the selenite impaired the catalysis of F1FO-ATPase, the mitochondrial permeability transition pore phenomenon was unaffected. Therefore, the reversible energy transduction mechanism of F1FO-ATPase can be oppositely regulated by selenite.

Variations of the Mycobacterium abscessus F-ATP synthase subunit a-c interface alter binding and potency of the anti-TB drug bedaquiline

The anti-tuberculosis therapeutic bedaquiline (BDQ) is used against Mycobacterium abscessus. In M. abscessus BDQ is only bacteriostatic and less potent compared to M. tuberculosis or M. smegmatis. Here we demonstrate its reduced ATP synthesis inhibition against M. abscessus inside-out vesicles, including the F1FO-ATP synthase. Molecular dynamics simulations and binding free energy calculations highlight the differences in drug-binding of the M. abscessus and M. smegmatis FO-domain at the lagging site, where the drug deploys its mechanistic action, inhibiting ATP synthesis. These data pave the way for improved anti-M. abscessus BDQ analogs.

In vivo and in vitro antiviral effect and mechanisms of rhein against nervous necrosis virus

Viral nervous necrosis (VNN) caused by nervous necrosis virus (NNV) is a major threat to the global aquaculture industry, resulting in huge economic losses. In this study, we evaluated a naturally anthraquinone, rhein, as a potential therapeutic agent against NNV. Rhein effectively inhibited NNV-induced cytopathic effects (CPE) at a concentration of 18.84 μM, with an inhibitory concentration (IC50) against NNV replication of 8.77 μM. Moreover, the study revealed a possible anti-NNV mechanism. Rhein could disrupt NNV-induced S-phase cell cycle arrest by inhibiting ATP synthesis, and cell cycle arrested in S phase is favorable for NNV replication, which in turn inhibits NNV replication. The therapeutic effect of rhein was also evaluated in vivo, where the survival rate of NNV infected grouper was increased by 26.7% with the treatment of 10 mg/kg rhein. Our findings demonstrated the potential of rhein as a pharmacological compound that exerts significant antiviral activity against NNV by modulating the cell cycle and ATP synthesis. Consequently, rhein has shown significant promise as a medication for the prevention and treatment of viral infections in aquaculture.

Malonate induces the browning of white adipose tissue in high-fat diet induced obesity model

Obesity increases the risk of various diseases, and many studies have examined prevention and treatment strategies. Browning of white adipocytes promotes triglyceride (TG) metabolism and is the new focus for treating obesity. This study investigated the role of malonate—a modulator of mitochondrial function—in adipocyte browning, and its potential as a therapeutic agent in obesity. Our findings revealed that malonate increased oxygen consumption without inhibiting ATP synthesis. Malonate induced expression of PRDM16—an important transcription factor for browning—and uncoupling protein 1 (beige adipocyte marker), suggesting that malonate induces browning in white adipocytes. In an obesity mouse model induced by a high-fat diet, malonate significantly reduced body weight and white adipose tissue weight, as well as improved insulin resistance. Importantly, malonate stimulated browning in white adipose tissue and maintained the mass of brown adipose tissue in the high-fat diet-induced obesity mouse model. We propose that manipulation of mitochondrial function by malonate is a promising therapeutic approach for obesity.

Cirsiliol and Quercetin Inhibit ATP Synthesis and Decrease the Energy Balance in Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin-Resistant Staphylococcus epidermidis (MRSE) Strains Isolated from Patients.

Polyphenols have attracted attention in the fight against antibiotic-resistant bacteria, as they show antibacterial action. Considering that polyphenols inhibit F1Fo-ATP synthase (ATP synthase) and that bacteria need a constant energy production to maintain their homeostasis, we evaluated the effect of two flavones, cirsiliol (tri-hy-droxy-6,7-dimethoxyflavone) and quercetin (3,3,4,5,7-pentahydroxyflavone), on energy production and intracellular ATP content in a methicillin-resistant Staphylococcus aureus (MRSA) strain and a methicillin-resistant Staphylococcus epidermidis (MRSE) strain isolated from patients, comparing the results to those obtained by treating the bacteria with oligomycin, a specific ATP synthase Fo moiety inhibitor. Real-time quantitative ATP synthesis and total ATP content of permeabilized Gram-positive bacteria were assayed by luminometry. The results showed that cirsiliol and quercetin inhibited ATP synthase and decreased the intracellular ATP levels in both strains, although the effect was higher in MRSE. In addition, while cirsiliol and quercetin acted immediately after the treatment, oligomycin inhibited ATP synthesis only after 30 min of incubation, suggesting that the different responses may depend on the different permeability of the bacterial wall to the three molecules. Thus, cirsiliol and quercetin could be considered potential additions to antibiotics due to their ability to target ATP synthase, against which bacteria cannot develop resistance.

Asteltoxins: Synthesis and Biological Studies

Asteltoxins belong to a group of polyene pyrone mycotoxins that are known to be potent inhibitors of mitochondrial ATP synthesis and ATP hydrolysis. Asteltoxin A was first isolated from the toxic maize cultures of Aspergillus stellatus. Several attempts have been made to synthesize asteltoxin A, starting with the synthesis of a bis(tetrahydrofuran) moiety that has been demonstrated previously in biosynthetic studies. This review highlights the fungal sources of asteltoxins, similar asteltoxins, biosynthetic pathways, their synthetic trials, and their biological activities. This review is the first of its kind covering the periods from 1979 to 2023.

Sodium aescinate improve behavioral performance by inhibiting dorsal raphe nucleus NLRP3 inflammasome in Post-traumatic stress disorder Rat Model

Growing evidence suggest that NLRP3 inflammasome activation in hippocampus and amygdala is involved in the pathophysiology of PTSD. Our previous studies have demonstrated that apoptosis of dorsal raphe nucleus (DRN) contributes to the pathological progression of PTSD. Recent studies by others have shown that in brain injury sodium aescinate (SA) has a protective effect on neurons by inhibiting inflammatory response pathways, thereby relieving symptoms. Here, we extend the therapeutic effects of SA to PTSD rats. We found that PTSD was associated with significant activation of the NLRP3 inflammasome in DRN, whereas administration of SA significantly inhibited DRN NLRP3 inflammasome activation and reduced DRN apoptosis level. SA also improved learning and memory ability and reduced anxiety and depression level in PTSD rats. In addition, NLRP3 inflammasome activation in DRN of PTSD rats impaired mitochondria function by inhibiting ATP synthesis and increasing ROS production, whereas SA can effectively reverse the pathological progression of mitochondria. We recommend SA as a new candidate for the pharmacological treatment of PTSD.

Elucidating the Mechanism of Action of the Gram-Negative-Pathogen-Selective Cyclic Antimicrobial Lipopeptide Brevicidine.

Due to the accelerated appearance of antimicrobial-resistant (AMR) pathogens in clinical infections, new first-in-class antibiotics, operating via novel modes of action, are desperately needed. Brevicidine, a bacterial nonribosomally produced cyclic lipopeptide, has shown potent and selective antimicrobial activity against Gram-negative pathogens. However, before our investigations, little was known about how brevicidine exerts its potent bactericidal effect against Gram-negative pathogens. In this study, we find that brevicidine has potent antimicrobial activity against AMR Enterobacteriaceae pathogens, with MIC values ranging between 0.5 μM (0.8 mg/L) and 2 μM (3.0 mg/L). In addition, brevicidine showed potent antibiofilm activity against the Enterobacteriaceae pathogens, with the same 100% inhibition and 100% eradication concentration of 4 μM (6.1 mg/L). Further mechanistic studies showed that brevicidine exerts its potent bactericidal activity by interacting with lipopolysaccharide in the outer membrane, targeting phosphatidylglycerol and cardiolipin in the inner membrane, and dissipating the proton motive force of bacteria. This results in metabolic perturbation, including the inhibition of ATP synthesis; the inhibition of the dehydrogenation of NADH; the accumulation of reactive oxygen species in bacteria; and the inhibition of protein synthesis. Finally, brevicidine showed a good therapeutic effect in a mouse peritonitis-sepsis model. Our findings pave the way for further research on the clinical applications of brevicidine to combat prevalent infections caused by AMR Gram-negative pathogens worldwide.