Tetramerization of upstream stimulating factor USF2 requires the elongated bent leucine zipper of the bHLH-LZ domain.

Upstream stimulating factors (USFs), including USF1 and USF2, are key components of the transcription machinery that recruit coactivators and histone-modifying enzymes. Using the classic basic helix-loop-helix leucine zipper (bHLH-LZ) domain, USFs bind the E-box DNA and form tetramers that promote DNA looping for transcription initiation. The structural basis by which USFs tetramerize and bind DNA, however, remains unknown. Here, we report the crystal structure of the complete bHLH-LZ domain of USF2 in complex with E-box DNA. We observed that the leucine zipper (LZ) of USF2 is longer than that of other bHLH-LZ family transcription factors and that the C-terminus of USF2 forms an additional α-helix following the LZ region (denoted as LZ-Ext). We also found the elongated LZ-Ext facilitates compact tetramer formation. In addition to the classic interactions between the basic region and DNA, we show a highly conserved basic residue in the loop region, Lys271, participates in DNA interaction. Together, these findings suggest that USF2 forms a tetramer structure with a bent elongated LZ-Ext region, providing a molecular basis for its role as a key component of the transcription machinery.

Surgical options and survival prognosis in geriatric patients beyond average lifespan with locally advanced gastric cancer: a propensity score-matched analysis.

BACKGROUND: The appropriateness of laparoscopic gastrectomy (LG) for super-geriatric patients with locally advanced gastric cancer (LAGC) is inconclusive, and the prognostic factors are also yet to be elucidated. Herein, we aimed to investigate the surgical and oncological outcomes of LG versus open gastrectomy (OG) for geriatric patients with LAGC who have outlived the average lifespan of the Chinese population (≥ 78 years). METHODS: This is a monocentric, retrospective, comparative study. A 1:1 propensity score matching (PSM) was performed to minimize selection bias and ensure well-balanced characteristics. The primary endpoint of interest was 3-year overall survival, while secondary endpoints included procedure-related variables, postoperative recovery indices, and complications. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify unfavorable prognostic factors. RESULTS: Of 196 eligible individuals, 107 underwent LG and 89 underwent OG, with a median age (interquartile range [IQR]) of 82 [79, 84] years. PSM yielded 61 matched pairs, with comparable demographic and tumor characteristics. The LG group had a significantly lower overall complication rate than the OG group (31.1% vs. 49.2%, P = 0.042), as well as shorter duration of postoperative hospital stay [12 (11, 13) vs. 13 (12, 15.5) d, P < 0. 001], less intraoperative blood loss [95 (75, 150) vs. 230 (195, 290) mL, P < 0.001], but a longer operative time [228 (210, 255.5) vs. 196 (180, 219.5) min, P < 0.001]. The times to first aerofluxus, defecation, liquid diet, and half-liquid diet were comparable. Kaplan-Meier analyses revealed no significant difference in 3-year overall survival between the groups, either in the entire cohort or in subgroups with different TNM staging. Moreover, Age-adjusted Charlson Comorbidity Index scores of > 6 [hazard ratio (HR) 4.003; P = 0.021] and pathologic TNM stage III (HR 3.816, P = 0.023) were independent unfavorable prognostic factors for long-term survival. CONCLUSIONS: LG performed by experienced surgeons offers the benefits of comparable or better surgical and oncological safety profiles than OG for super-geriatric patients with LAGC.

Effect of anterior communicating artery patency on the flow velocity in bilateral carotid artery stenosis after carotid endarterectomy.

BACKGROUND: The effect of anterior communicating artery (ACoA) patency on the flow velocity of the extracranial carotid arteries is unclear. METHODS: A total of 285 patients with carotid artery stenosis were included between January 2019 and January 2021. All patients received unilateral carotid endarterectomy (CEA). The patients were classified into ACoA-patent (161) and ACoA-nonpatent (124) groups using digital subtraction angiography (DSA) and/or computed tomography angiography (CTA). The peak systolic velocity (PSV) and end-diastolic velocity (EDV) measured by carotid duplex ultrasonography (CDU) were compared between both groups, pre- and post-CEA. RESULTS: There was no significant difference in the risk factors for cerebrovascular disease between the two groups. Within 1 week after CEA, the PSV and EDV on operative and nonoperative carotid (contralateral carotid in the same patient) arteries decreased significantly (both p < 0.01). Comparison of nonoperative carotid artery pre- and post-CEA between the two groups showed that post-CEA PSV and EDV in the ACoA-patent group were significantly lower than that of pre-CEA (PSV and EDV, t = 11.507 and 6.716, respectively, both p < 0.001) (according to the Society of Radiologists in Ultrasound Consensus Conference [SRUCC] PSV standard). There was no significant difference in the ACoA-nonpatent group (PSV: t = 1.924, p = 0.057; EDV: t = 1.237, p = 0.218). In the nonoperative carotid artery of the ACoA-patent group, the degree of stenosis assessed by CDU was inconsistent with that of DSA/CTA (κ = 0.294), whereas that in the ACoA-nonpatent group had a high consistency (κ = 0.982). Among 161 ACoA-patent cases, 68 showed overestimated stenosis. CONCLUSIONS: The patent ACoA increases PSV and EDV, causing an overestimation of carotid artery stenosis.

Discovery of novel benzimidazole derivatives as potent potassium-competitive acid blockers for the treatment of acid-related diseases.

H+, K+-ATPase, as the most critical enzyme in gastric acid secretion, has long been an attractive target for the treatment of acid-related diseases. In this study, a series of benzimidazole derivatives were designed and synthesized through conformational restriction and skeleton hopping strategies by using vonoprazan as the lead compound. Among them, compounds A12 (IC50 = 9.32 µM) and A18 (IC50 = 5.83 µM) showed better inhibition at the enzyme level. In addition, gastric acid secretion inhibition was assessed in vivo, and the results showed that A12 and A18 significantly inhibited basal gastric acid secretion, 2-deoxy-d-glucose (2DG) stimulated gastric acid secretion and histamine-stimulated gastric acid secretion. In further in vitro metabolic experiments, A12 and A18 demonstrated excellent stability and low toxicity. Pharmacokinetic studies showed that the p.o. and i.v. half-lives of A18 were 3.21 h and 8.67 ± 1.15 h, respectively. In summary, A18 might be a novel and effective potassium-competitive acid blocker, and this study provides strong support for it use in the treatment of acid-related diseases.

Synthesis and Anti-Neuroinflammatory Activity of 1,7-diphenyl-1,4-heptadien-3-ones in LPS-Stimulated BV2 Microglia Via Inhibiting NF-κB/MAPK Signaling Pathways.

A series of 1,7-diphenyl-1,4-heptadien-3-ones with various substituents (HO-, CH3O-, CH3-, Cl-) on the phenyl rings were synthesized and evaluated for anti-neuroinflammatory effects in LPS-stimulated BV2 microglia. The pharmacological results showed that the target compounds bearing methoxy groups greatly inhibited LPS-induced NO release, and that the active compounds CU-19 and CU-21 reduced the level of NO, TNF-α, IL-6 and PGE-2, downregulated the expression of COX-2 and iNOS in LPS-stimulated BV2 cells. A study of the mechanism of action revealed that CU-19 and CU-21 inhibited the nuclear translocation of NF-κB and phosphorylation of MAPKs (ERK, JNK, and p38). A preliminary pharmacokinetic study in rats revealed that the pharmacokinetic properties of CU-19 and CU-21 were dramatically ameliorated in comparison with the pharmacokinetic properties of curcumin.

Enhancement of Dissolving Capacity and Reducing Gastric Mucosa Irritation by Complex Formation of Resibufogenin with ß-Cyclodextrin or 2-Hydroxypropyl-ß-cyclodextrin.

Resibufogenin (RBG) is a natural medicinal ingredient with promising cardiac protection and antitumor activity. However, poor solubility and severe gastric mucosa irritation restrict its application in the pharmaceutical field. In this study, the inclusion complex of RBG with ß-cyclodextrin (ß-CD) and 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) was prepared using the co-evaporation method, and the molar ratio of RBG to CD was determined to be approximately 1:2 by continuous variation plot for both CDs. The formation of inclusion complexes between RBG and each CD (RBG/ß-CD and RBG/HP-ß-CD) was evaluated by phase solubility study, Fourier transform infrared spectroscopy, and thin-layer chromatography. Powder X-ray diffraction and differential scanning calorimetry confirmed drug amorphization and encapsulation in the molecular cage for both CDs. Moreover, the inclusion complexes' morphologies were observed using scanning electron microscopy. The dissolution rate of the inclusion complexes was markedly improved compared to that of RBG, and the complexes retained their antitumor activity, as shown in the in vitro cytotoxicity assay on a human lung adenocarcinoma cancer (A549) cell line. Moreover, less gastric mucosal irritation was observed for the inclusion complex. Thus, the inclusion complex should be considered a promising strategy for the delivery of poorly water-soluble anticancer agents, such as RBG.

Activation of the RhoA-YAP-ß-catenin signaling axis promotes the expansion of inner ear progenitor cells in 3D culture.

Cellular mechanotransduction plays an essential role in the development and differentiation of many cell types, but if and how mechanical cues from the extracellular matrix (ECM) influence the fate determination of inner ear progenitor cells (IEPCs) remains largely unknown. In the current study, we compared the biological behavior of IEPCs in Matrigel-based suspension and encapsulated culture systems, and we found that the mechanical cues from the ECM promote the survival and expansion of IEPCs. Furthermore, we found that the mechanical cues from the ECM induced the accumulation of Ras homolog family member A (RhoA) and caused the polymerization of actin cytoskeleton in IEPCs. These changes in turn resulted in increased Yes-associated protein (YAP) nuclear localization and enhanced expansion of IEPCs, at least partially through upregulating the canonical Wnt signaling pathway. We therefore provide the first demonstration that the RhoA-YAP-ß-catenin signaling axis senses and transduces mechanical cues from the ECM and plays crucial roles in promoting the expansion of IEPCs.

Dual-pH Sensitive Charge-Reversal Drug Delivery System for Highly Precise and Penetrative Chemotherapy.

PURPOSE: The complex physiological barriers impose extremely conflicting demands on systemic drug delivery, so both particle size and surface charge of the nanoplatforms become vital factors. As a carbon-based nanomaterial with excellent optical properties, carbon dots are not suitable for direct systemic transport in vivo, which limits their application in the field of biomedical imaging, especially in the areas of diagnosis and cancer treatment. Liposomes have been developed as universal nanocarriers for various drugs. In this study, we aimed to build a highly precise and penetrative drug delivery system (DDS) using carbon dots encapsulated by liposomes. METHODS: Carbon dots (CDs) were synthesized by the hydrothermal method using citric acid and ethylenediamine. Furthermore, simian virus 40 large T-antigen derived the nuclear targeting sequence (NLS) was bonded on the surface of CDs to obtain CDs-NLS. The antitumor drug doxorubicin was loaded onto the CDs-NLS through an acid-labile hydrazine bond to obtain DOX@CDs. Finally, DOX@CDs were encapsulated in aqueous centers of folate-coated and pH-sensitive liposomes, named pHSL-FA. RESULTS: In this paper, a nucleus-targeted nanocomposite (DOX@CDs), which bonds with the nuclear targeting sequence (NLS) and the anticancer drug doxorubicin (DOX), has physicochemical properties of particle size of about 3.8 nm, zeta potential of +31.8 mV and high quantum yield of 64.53%. The negatively charged folate-coated and pH-sensitive liposomes (pHSL-FA) are used as a carrier to reverse the surface charge of DOX@CDs. Compared to free DOX@CDs, pHSL-FA show higher tumor accumulation in 4 T1 tumor-bearing mice and further improve cytotoxicity to tumor cells. CONCLUSIONS: This work proposes a unique nanomedical approach that enables the precise delivery of chemotherapy drugs and significantly reduces side effects, which is promising for clinical translation.

Two New Indole Alkaloids from Toad Venom of Bufo bufo gargarizans.

Two new indole alkaloids, Bufotenidine B (2) and Bufocarboline A (6), along with seven known indole alkaloids (1, 3-5, and 7-9) and three organic acids (10-12), were isolated from the water extract of toad venom. The structures of the new alkaloids were elucidated by extensive spectroscopic methods. The absolute configurations of 4, 6, and 8 were determined for the first time by electronic circular dichroism (ECD) calculations. The cytotoxic activity of all compounds was tested against human malignant melanoma cells A375 by the MTT method, and no antitumor activity was observed.

α-Pyrones, secondary metabolites from fungus Cephalotrichum microsporum and their bioactivities.

Cephalotrichum microsporum (SYP-F 7763) was a fungus isolated from the rhizosphere soil of traditional Chinese medicine Panax notoginseng. The EtOAc extract of Cephalotrichum microsporum cultivated on sterilized moistened-rice medium was separated by various chromatographic techniques, which yielded 11 metabolites (1-11) of this fungus. On the basis of the widely spectroscopic data, the chemical structures of isolated metabolites were determined, most of which were α-pyrones, including 5 compounds (4-7, and 10) unreported. In the anti-bacterial bioassay, compound 1 displayed significant inhibitory effects on three pathogenic bacteria, MR S. aureus, S. aureus, and B. cereus. α-Pyrones 2, 3, and 5-7 also displayed moderate inhibitory effects on MR S. aureus, S. aureus, and B. subtilis, which could be the major anti-bacterial constituents of Cephalotrichum microsporum. Additionally, compounds 1, 4, and 5 displayed significant cytotoxicity on five human cancer cell lines, with the IC50 values < 20 µM, which are more effective than positive control 5-fluorouracil. Therefore, α-pyrones were important secondary metabolites of Cephalotrichum microsporum, which displayed anti-bacterial and anti-tumor activities.

Estrogen Receptors Are Involved in the Neuroprotective Effect of Silibinin in Aß1-42-Treated Rats.

Alzheimer's disease (AD) is a progressive neurodegenerative disease that is characterized by a cascade of pathologic changes. A widely discussed theory indicates that amyloid ß (Aß) peptides are the causative agents of AD. Silibinin, a flavonoid derived from milk thistle, is well known for its hepato-protective activities and we have reported the neuroprotective effects of silibinin. In this study, we investigated the role of estrogen receptors (ERs) in silibinin's neuroprotective effect on Aß1-42-injected rats. Results of Morris water maze and novel object-recognition tests demonstrated that silibinin significantly attenuated Aß1-42-induced memory impairment. Silibinin attenuated ERs and PI3K-Akt pathways, as well as modulated mitogen-activated protein kinases in the hippocampus of Aß1-42-injected rats. Taken together, silibinin is a potential candidate in the treatment of Alzheimer's disease.

A new indole alkaloid from the traditional Chinese medicine Chansu.

A new indole alkaloid N'-formylserotonin (1), along with five known indole alkaloids N'-methylserotonin (2), 5-hydroxy-1H-indole-3-carbaldehyde (3), N-acetylserotonin (4), 6-hydroxy-1-oxo-3,4-dihydro-ß-carboline (5), and bufoserotoin C (6), were isolated from the water extract of traditional Chinese medicine Chansu. Their structures were elucidated on the basis of spectral analyses. The cytotoxicities of 1-6 against human lung adenocarcinoma epithelial cells A549 were tested using the MTT method. Compound 6 exhibited stronger cytotoxic effect than 5-FU, and 1-5 showed no cytotoxic effects. Bufoserotonin C is one of the cytotoxic components in water-soluble extract of Chansu.

Silibinin ameliorates Aß25-35-induced memory deficits in rats by modulating autophagy and attenuating neuroinflammation as well as oxidative stress.

Alzheimer's disease (AD) is a progressive, neurodegenerative disease. Accumulating evidence suggests that inflammatory response, oxidative stress and autophagy are involved in amyloid ß (Aß)-induced memory deficits. Silibinin (silybin), a flavonoid derived from the herb milk thistle, is well known for its hepatoprotective activities. In this study, we investigated the neuroprotective effect of silibinin on Aß25-35-injected rats. Results demonstrated that silibinin significantly attenuated Aß25-35-induced memory deficits in Morris water maze and novel object-recognition tests. Silibinin exerted anxiolytic effect in Aß25-35-injected rats as determined in elevated plus maze test. Silibinin attenuated the inflammatory responses, increased glutathione (GSH) levels and decreased malondialdehyde (MDA) levels, and upregulated autophagy levels in the Aß25-35-injected rats. In conclusion, silibinin is a potential candidate for AD treatment because of its anti-inflammatory, antioxidant and autophagy regulating activities.

ERß up-regulation was involved in silibinin-induced growth inhibition of human breast cancer MCF-7 cells.

We previously reported that silibinin induced a loss of cell viability in breast cancer (MCF-7) cells by ERα down-regulation. But whether this cytotoxicity depends on another estrogen receptor, ERß, has yet to be elucidated. Therefore, we sought to explore the effects of ERß modulation on cell viability by using an ERß-selective agonist (Diarylprepionitrile, DPN) and an antagonist (PHTPP). Our data demonstrated that ERß served as a growth suppressor in MCF-7 cells, and the incubation of silibinin, elevated ERß expression, resulting in the tumor growth inhibition. The cytotoxic effect of silibinin was diminished by PHTPP and enhanced by DPN. Silencing of ERß by siRNA confirmed these results. Apoptotic cascades, including the sequential activation of caspase-9 and -6, and finally the cleavage of caspase substrates, PARP and ICAD, caused by treatment with silibinin, were all repressed by PHTPP pre-treatment but exacerbated by DPN. Unlike ERα, ERß did not involve autophagic process in the regulation, since neither autophagic inhibitor (3-MA) nor the inducer (rapamycin) affected the cell survival rates regardless ERß activity. Taken together, silibinin induced apoptosis through mitochondrial pathway by up-regulating ERß pathways in MCF-7 cells without the involvement of autophagy.

Protective Effect of Silibinin on Learning and Memory Impairment in LPS-Treated Rats via ROS-BDNF-TrkB Pathway.

Silibinin, a flavonoid derived from the herb milk thistle (Silybum marianum), has been used as a hepato-protectant in the clinical treatment of liver disease. In the present study, the effect of silibinin on lipopolysaccharide (LPS)-induced neuroinflammatory impairment in rats is investigated. Injection of LPS into lateral ventricle caused learning and memory impairment. Rats were treated with silibinin to see the effect in comparison with resveratrol as a positive control. Y-maze and Morris water maze tests showed that silibinin significantly attenuated memory damage caused by LPS treatment. At the molecular analysis, the levels of IL-1ß and of IL-4 in the hippocampus were decreased and enhanced, respectively, by the treatment with silibinin. NF-κB expression was attenuated by silibinin treatment. Furthermore, generation of total reactive oxygen species (ROS) in the hippocampus was elevated in silibinin-treated groups, and so were the expressions of brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB). At the same time, LPS-induced reduction of neurons in hippocampus was reversed by silibinin. In conclusion, silibinin ameliorated the impairment of learning and memory of LPS-injection rats, possibly due to the activation of ROS-BDNF-TrkB pathway in the hippocampus as well as the suppression of inflammatory response. This study gives an insight on the beneficial consequences of ROS in central nervous system. Silibinin might be a potential candidate drug for neurodegenerative diseases.

Gelatin promotes murine fibrosarcoma L929 cell detachment and protects the cells from TNFα-induced cytotoxicity.

PURPOSE: Gelatin has been considered to exist as intermediate substance of collagen catabolism in tissue remodeling or under inflammatory conditions. We have initiated the study on possible biological functions of gelatin that can exist temporally and locally under the conditions of remodeling and inflammation Materials and methods: To this purpose, we investigated cell proliferation and survival on gelatin-coated dishes and the response to tumor necrosis factor α (TNFα)-induced cytotoxicity in L929 cells. Autophagy level, ATP level, and ROS generation are examined. RESULTS: L929 cells detached from the gelatin-coated dishes and formed multicellular aggregates. TNFα-induced cytotoxicity in L929 cells was inhibited by gelatin-coating culture. The cells on gelatin-coated dishes showed reduced cellular ATP levels and increased adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation, leading to increased ROS generation and autophagy. CONCLUSION: This study showed that gelatin-coated culture protected L929 cells from TNFα-induced cytotoxicity and suggested for a possible pathophysiological function of gelatin in regulating cellular functions.

A New Indole Alkaloid from the Toad Venom of Bufo bufo gargarizans.

A new indole alkaloid named bufobutarginine (1), along with three known bufotenines, namely, serotonin (2), bufotenidine (3), and bufotenine (4), were isolated from the water extract of toad venom. Their structures were elucidated by spectral methods. This is the first time that arginine has been found to be involved in the biosynthesis of bufotenines in parotid of toad. The cytotoxic activities of these compounds have been assayed against A375 and A549 cell lines by the MTT method; however, they showed no cytotoxic activities.

[Cloning, prokaryotic expression and function of the Bufo bufo gargarizans tryptophan hydroxylase I gene].

Tryptophan hydroxylase I（TPH1） catalases the 5-hydroxylation reaction of L-Trp, which is the rate-limiting step in the synthesis of serotonin. Serotonin, a major component of Bufonis venenum, is involved in numerous physiological functions as an important neurotransmitter. In this study, BbgTPH1 cDNA was cloned from the parotid gland of Bufo bufo gargarizans. Genetic engineering techniques were used to construct a recombinant prokaryotic fusion expression plasmid pMAL-BbgTPH1, and the induced conditions to express the recombinant BbgTPH1 in E. coli TB1 cells were optimized. The full length of BbgTPH1 is 1 984 bp (GenBank accession No. JQ768313) with a 1 443 bp open reading frame (ORF) encoding a 480 amino acid residues. The deduced protein molecular weight is 55.2 k Da and its theoretical isoelectric point is 5.58. The sequence includes conserved domain and special signal sequence of the aromatic amino acid hydroxylase (AAAH) superfamily. Homologous alignment showed that BbgTPH1 shared a high homology with other species. Phylogenetic tree showed the closest relative to BbgTPH1 was Xenopus tropical-TPH1. The best induction conditions of recombinant BbgTPH1 were 0.5 mmol·L(-1) IPTG at 20 ℃ for 8 h. The function of BbgTPH1 was identified by in vitro enzymatic reaction and the recombinant BbgTPH1 was able to produce 5-hydroxytryptophan by catalyzing tryptophan. This study represents the first time of cloning and identification of the function of TPH1 in Bufo genus. The results of this study will be an important foundation for future studies of biosynthesis of bufotenines in the parotid gland of B. bufo gargarizans.

Type I collagen gel protects murine fibrosarcoma L929 cells from TNFα-induced cell death.

Murine fibrosarcoma L929 cells have been used to test efficacy of proinflammatory cytokine TNFα. In the present study, we reported on protective effect of type I collagen gel used as L929 cell culture. L929 cell grew and proliferated well on collagen gel. However, the L929 cells exhibited cobblestone-like morphology which was much different from the spread fusiform shape when cultured on conventional cell dishes as well as the cells tended to aggregate. On conventional cell culture dishes, the cells treated with TNFα became round in shape and eventually died in a necroptotic manner. The cells cultured on collagen gel, however, were completely unaffected. TNFα treatment was reported to induce autophagy in L929 cells on the plastic dish, and therefore we investigated the effect of collagen gel on induction of autophagy. The results indicated that autophagy induced by TNFα treatment was much reduced when the cells were cultured on collagen gel. In conclusion, type I collagen gel protected L929 cell from TNFα-induced cell death.