-
BJC Reports 2024Checkpoint inhibitors, which generate durable responses in many cancer patients, have revolutionized cancer immunotherapy. However, their therapeutic efficacy is...
BACKGROUND/OBJECTIVES
Checkpoint inhibitors, which generate durable responses in many cancer patients, have revolutionized cancer immunotherapy. However, their therapeutic efficacy is limited, and immune-related adverse events are severe, especially for monoclonal antibody treatment directed against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), which plays a pivotal role in preventing autoimmunity and fostering anticancer immunity by interacting with the B7 proteins CD80 and CD86. Small molecules impairing the CTLA-4/CD80 interaction have been developed; however, they directly target CD80, not CTLA-4.
SUBJECTS/METHODS
In this study, we performed artificial intelligence (AI)-powered virtual screening of approximately ten million compounds to identify those targeting CTLA-4. We validated the hits molecules with biochemical, biophysical, immunological, and experimental animal assays.
RESULTS
The primary hits obtained from the virtual screening were successfully validated in vitro and in vivo. We then optimized lead compounds and obtained inhibitors (inhibitory concentration, 1 micromole) that disrupted the CTLA-4/CD80 interaction without degrading CTLA-4.
CONCLUSIONS
Several compounds inhibited tumor development prophylactically and therapeutically in syngeneic and CTLA-4-humanized mice. Our findings support using AI-based frameworks to design small molecules targeting immune checkpoints for cancer therapy.
PubMed: 38312352
DOI: 10.1038/s44276-023-00035-5 -
Food Additives & Contaminants. Part A,... Mar 2024In this work, we investigated the reaction of cyclamate with hypochlorous acid (HOCl) in simulated gastric juice. The reaction products were detected by high-performance...
In this work, we investigated the reaction of cyclamate with hypochlorous acid (HOCl) in simulated gastric juice. The reaction products were detected by high-performance liquid chromatography diode array detection (HPLC-DAD) and ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). We also explored the changes in product concentration as a function of reaction time, cyclamate and HOCl concentrations. Cyclamate reacted with hypochlorous acid instantly in the simulated gastric fluid. N, N-dichlorcyclohexylamine and cyclohexylamine were both detected when the HOCl concentration was at millimole. Cyclohexylamine can only be found when HOCl concentration was at micromole. N, N-dichlorcyclohexylamine and cyclohexylamine concentrations both increased when cyclamate concentration increased under the millimole level of HOCl. As an important reactive oxygen species, hypochlorous acid (HClO) is produced in various physiological processes. The abnormal rise of the HClO level is associated with many inflammatory diseases. Chronic gastritis associated with is a multistep, progressive, life-long inflammation. So, chronic gastritis infected with may cause cyclamate metabolizing into cyclohexylamine
Topics: Humans; Cyclamates; Hypochlorous Acid; Cyclohexylamines; Tandem Mass Spectrometry; Gastritis
PubMed: 38252774
DOI: 10.1080/19440049.2024.2306534 -
Science Advances Jan 2024Photocatalytic water oxidation is a key half-reaction for various solar-to-fuel conversion systems but requires simultaneous water affinity and hole accumulation at the...
Photocatalytic water oxidation is a key half-reaction for various solar-to-fuel conversion systems but requires simultaneous water affinity and hole accumulation at the photocatalytic site. Here, we present the rational design and synthesis of an ionic-type covalent organic framework (COF) named tetraphenylporphyrin cobalt and cobalt bipyridine complex (CoTPP-CoBpy) COF, combining cobalt porphyrin and cobalt bipyridine building blocks as a photocatalyst for water oxidation. The good dispersibility of porous large-size (>2 micrometers) COF nanosheets (≈1.45 nanometers) facilitates local water collection; the ultrafast triplet-state charge transfer (1.8 picoseconds) and prolonged charge separation (1.2 nanoseconds) further contribute to the efficient accumulation of holes in the CoTPP moiety, leading to a photocatalytic dioxygen production rate of 7323 micromoles per gram per hour. Moreover, we have identified an end-on superoxide radical (O) intermediate at the active site of the CoTPP moiety and proposed an electron-intermediate cascade mechanism that elucidates the synergistic coupling of electron relay (S-T-T') and intermediate evolution during the photocatalytic process.
PubMed: 38232160
DOI: 10.1126/sciadv.adk8564 -
Physiological Research Dec 2023To investigate the exact effects of dietary choline on hypertensive heart disease (HHD) and explore the potential mechanisms, male spontaneously hypertensive rats (SHR)...
To investigate the exact effects of dietary choline on hypertensive heart disease (HHD) and explore the potential mechanisms, male spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) were randomly divided into five groups as follows: WKY group, WKY + Choline group, SHR group, SHR + Choline group, and SHR + Choline + NaHS group. In choline treatment groups, rats were fed with 1.3% (w/v) choline in the drinking water for 3 months. The rats in the SHR + Choline + NaHS group were intraperitoneally injected with NaHS (100 micromol/kg/day, a hydrogen sulfide (H2S) donor) for 3 months. After 3 months, left ventricular ejection fraction (LVEF) and fractional shortening (LVFS), the indicators of cardiac function measured by echocardiography, were increased significantly in SHR as compared to WKY, although there was no significant difference in collagen volumes and Bax/Bcl-2 ratio between the two groups, indicating the early stage of cardiac hypertrophy. There was a significant decrease in LVEF and LVFS and an increase in collagen volumes and Bax/Bcl-2 ratio in SHR fed with choline, meanwhile, plasma H2S levels were significantly decreased significantly in SHR fed with choline accompanying by the decrease of cystathionine-gamma-lyase (CSE) activity. Three months of NaHS significantly increased plasma H2S levels, ameliorated cardiac dysfunction and inhibited cardiac fibrosis and apoptosis in SHR fed with choline. In conclusion, choline aggravated cardiac dysfunction in HHD through inhibiting the production of endogenous H2S, which was reversed by supplementation of exogenous H2S donor.
Topics: Rats; Male; Animals; Hydrogen Sulfide; Rats, Inbred SHR; Stroke Volume; bcl-2-Associated X Protein; Ventricular Function, Left; Hypertension; Rats, Inbred WKY; Heart Diseases; Collagen; Sulfides
PubMed: 38215059
DOI: 10.33549/physiolres.935075 -
Current Diabetes Reviews Jan 2024Cell culture plays a crucial role in addressing fundamental research questions, particularly in studying insulin resistance (IR) mechanisms. Multiple in vitro models are...
UNLABELLED
Cell culture plays a crucial role in addressing fundamental research questions, particularly in studying insulin resistance (IR) mechanisms. Multiple in vitro models are utilized for this purpose, but their technical distinctions and relevance to in vivo conditions remain unclear. This study aims to assess the effectiveness of existing in vitro models in inducing IR and their ability to replicate in vivo IR conditions.
BACKGROUND
Insulin resistance (IR) is a cellular condition linked to metabolic disorders. Despite the utility of cell culture in IR research, questions persist regarding the suitability of various models. This study seeks to evaluate these models' efficiency in inducing IR and their ability to mimic in vivo conditions. Insights gained from this research could enhance our understanding of model strengths and limitations, potentially advancing strategies to combat IR and related disorders.
OBJECTIVE
1- Investigate the technical differences between existing cell culture models used to study molecular mediators of insulin resistance (IR). 2- Compare the effectiveness of present in vitro models in inducing insulin resistance (IR). 3- Assess the relevance of the existing cell culture models in simulating the in vivo conditions and environment that provoke the induction of insulin resistance (IR).
METHODS AND MATERIAL
In vitro, eight sets of 3T3-L1 cells were cultured until they reached 90% confluence. Subsequently, adipogenic differentiation was induced using a differentiation cocktail (media). These cells were then divided into four groups, with four subjected to normal conditions and the other four to hypoxic conditions. Throughout the differentiation process, each cell group was exposed to specific factors known to induce insulin resistance (IR). These factors included 2.5nM tumor necrosis factor-alpha (TNFα), 20 ng/ml interleukin-6 (IL-6), 10 micromole 4-hydroxynonenal (4HNE), and high insulin (HI) at a concentration of 100nM. To assess cell proliferation, DAPI staining was employed, and the expression of genes associated with various metabolic pathways affected by insulin resistance was investigated using Real-Time PCR. Additionally, insulin signaling was examined using the Bio-plex Pro cell signaling Akt panel.
RESULTS
We induced insulin resistance in 3T3-L1 cells using IL-6, TNFα, 4HNE, and high insulin in both hypoxic and normoxic conditions. Hypoxia increased HIF1a gene expression by approximately 30% (P<0.01). TNFα reduced cell proliferation by 10-20%, and chronic TNFα treatment significantly decreased mature adipocytes due to its cytotoxicity. We assessed the impact of insulin resistance (IR) on metabolic pathways, focusing on genes linked to branched-chain amino acid metabolism, detoxification, and chemotaxis. Notably, ALDH6A1 and MCCC1 genes, related to amino acid metabolism, were significantly affected under hypoxic conditions. TNFα treatment notably influenced MCP-1 and MCP-2 genes linked to chemotaxis, with remarkable increases in MCP-1 levels and MCP-2 expression primarily under hypoxia. Detoxification-related genes showed minimal impact, except for a significant increase in MAOA expression under acute hypoxic conditions with TNFα treatment. Additional genes displayed varying effects, warranting further investigation. To investigate insulin signaling's influence in vitro by IRinducing factors, we assessed phospho-protein levels. Our results reveal a significant p-Akt induction with chronic high insulin (10%) and acute TNFα (12%) treatment under hypoxia (both P<0.05). Other insulin resistance-related phospho-proteins (GSK3B, mTOR, PTEN) increased with IL-6, 4HNE, TNFα, and high insulin under hypoxia, while p-IRS1 levels remained unaffected.
CONCLUSION
In summary, different in vitro models using inflammatory, oxidative stress, and high insulin conditions under hypoxic conditions can capture various aspects of in vivo adipose tissue insulin resistance (IR). Among these models, acute TNFα treatment may offer the most robust approach for inducing IR in 3T3-L1 cells.
PubMed: 38204253
DOI: 10.2174/0115733998263359231211044539 -
Autophagy Jun 2024Senecavirus A (SVA) is a newly emerging picornavirus associated with swine vesicular lesions and neonatal mortality, threatening the global pig industry. Despite...
Senecavirus A (SVA) is a newly emerging picornavirus associated with swine vesicular lesions and neonatal mortality, threatening the global pig industry. Despite sustained efforts, the molecular mechanisms of SVA pathogenesis have not yet been fully elucidated. Here, we demonstrate for the first time that SVA infection can induce complete mitophagy in host cells, which depends on SVA replication. Mitophagy has been subsequently proven to promote SVA replication in host cells. Genome-wide screening of SVA proteins involved in inducing mitophagy showed that although VP2, VP3, 2C, and 3A proteins can independently induce mitophagy, only the 2C protein mediates mitophagy through direct interaction with TUFM (Tu translation elongation factor, mitochondrial). The glutamic acids at positions 196 and 211 of TUFM were shown to be two key sites for its interaction with 2C protein. Moreover, TUFM was discovered to interact directly with BECN1 and indirectly with the ATG12-ATG5 conjugate. Further experiments revealed that TUFM needs to undergo ubiquitination modification before being recognized by the macroautophagy/autophagy receptor protein SQSTM1/p62, and E3 ubiquitin ligase RNF185 catalyzes K27-linked polyubiquitination of TUFM through the interaction between RNF185's transmembrane domain 1 and TUFM to initiate SVA-induced mitophagy. The ubiquitinated TUFM is recognized and bound by SQSTM1, which in turn interacts with MAP1LC3/LC3, thereby linking the 2C-anchored mitochondria to the phagophore for sequestration into mitophagosomes, which ultimately fuse with lysosomes to achieve complete mitophagy. Overall, our results elucidated the molecular mechanism by which SVA induces mitophagy to promote self-replication and provide new insights into SVA pathogenesis.: aa: amino acid; Baf A1: bafilomycin A; BHK-21: baby hamster kidney-21; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; co-IP: co-immunoprecipitation; CQ: chloroquine; DAPI: 4',6-diamidino-2'-phenylindole; DMSO: dimethyl sulfoxide; EGFP: enhanced green fluorescent protein; ER: endoplasmic reticulum; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; GST: glutathione S-transferase; HA: hemagglutinin; hpi: hours post-infection; hpt: hours post-transfection; IPTG: isopropyl β-D-1-thiogalactopyranoside; mAb: monoclonal antibody; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAVS: mitochondrial antiviral signaling protein; Mdivi-1: mitochondrial division inhibitor-1; MOI: multiplicity of infection; mRFP: monomeric red fluorescent protein; MS: mass spectrometry; ORF: open reading frame; PBS: phosphate-buffered saline; SD: standard deviation; SQSTM1/p62: sequestosome 1; ST: swine testis; SVA: Senecavirus A; TCID: 50% tissue culture infectious dose; TIMM23: translocase of inner mitochondrial membrane 23; TM: transmembrane; TOMM20: translocase of outer mitochondrial membrane 20; TUFM: Tu translation elongation factor, mitochondrial; Ub: ubiquitin; UV: ultraviolet; VDAC1: voltage dependent anion channel 1; WT: wild-type; μg: microgram; μm: micrometer; μM: micromole.
Topics: Mitophagy; Humans; Ubiquitination; Virus Replication; Ubiquitin-Protein Ligases; Animals; Picornaviridae; HeLa Cells; Mitochondrial Proteins; Mitochondria; Viral Nonstructural Proteins; Protein Binding; Lysine; Swine; HEK293 Cells
PubMed: 38084826
DOI: 10.1080/15548627.2023.2293442 -
European Journal of Medicinal Chemistry Jan 2024The shortage of cholesterol gallstones treatment intensifies the need to discover of effective small molecule drugs. Clinical follow-up and studies have found that...
The shortage of cholesterol gallstones treatment intensifies the need to discover of effective small molecule drugs. Clinical follow-up and studies have found that activation of somatostatin receptor subtype 5 (SSTR5) reduce gallbladder contraction and thus increase the risk of cholesterol gallstones, implying that antagonizing SSTR5 may promote gallbladder emptying and reduce the formation of gallstones. Herein, we discovered novel SSTR5 antagonists and firstly investigated its effects on cholesterol gallstone. From loperamide, a reported seed structure with micromole activity, we identified optimal compound 23 as an SSTR5 antagonist exhibiting single-digit nanomolar potency, low hERG inhibition and oral availability. Further in vivo evaluation revealed that 23 significantly promoted gallbladder emptying. Moreover, in a mouse cholesterol gallstone model, 23 (3 mg/kg) effectively reduced the cholesterol gallstones formation, showing better efficacy than the clinical first-line drug UDCA (60 mg/kg), providing a new insight into the development of anti-gallstone drugs.
Topics: Animals; Mice; Gallstones; Receptors, Somatostatin; Cholesterol
PubMed: 38070432
DOI: 10.1016/j.ejmech.2023.116017 -
BioTechniques Feb 2024Hydrogen sulfide (HS), an endogenous gasotransmitter, has potential applications in several conditions. However, its quantification in simulated physiological solutions...
Hydrogen sulfide (HS), an endogenous gasotransmitter, has potential applications in several conditions. However, its quantification in simulated physiological solutions is a major challenge due to its gaseous nature and other physicochemical properties. This study was designed to compare four commonly used HS detection and quantification methods in aqueous solutions. The four techniques compared were one colorimetric, one chromatographic and two electrochemical methods. Colorimetric and chromatographic methods quantified HS in millimolar and micromole ranges, respectively. The electrochemical methods quantified HS in the nanomole and picomole ranges and were less time-consuming. The HS quantification method should be selected based on the specific requirements of a research project in terms of sensitivity, response time and cost-effectiveness.
Topics: Hydrogen Sulfide; Colorimetry; Spectrum Analysis; Electrochemical Techniques
PubMed: 38059376
DOI: 10.2144/btn-2023-0075 -
Chemosphere Feb 2024Nonradical species with great resistance to interference have shown great advantages in complex wastewater treatment. Herein, a novel system constructed by biodegradable...
Nonradical species with great resistance to interference have shown great advantages in complex wastewater treatment. Herein, a novel system constructed by biodegradable tetrakis-(4-carboxyphenyl)-porphyrinatoiron(III) (Fe-TCPP) and peroxymonosulfate (PMS) was proposed for facile decontamination. Nonradical pathway is observed in Fe-TCPP/PMS, where O and high-valent iron-oxo species play dominant roles. The genres and valence of high-valent iron-oxo species, including iron(IV)-oxo porphyrin radical-cationic species [OFe-TCPP] and iron(IV)-hydroxide species [Fe-TCPP(OH)], are ascertained, along with their generation mechanism. The axial ligand on the iron axial site affects the ground spin state of Fe-TCPP, further influencing the thermodynamic reaction pathway of active species. With trace catalyst in micromoles, Fe-TCPP exhibits high efficiency by degrading bisphenol S (BPS) completely within 5 min, while Co/PMS can only achieve a maximum of 26.2% under identical condition. Beneficial from nonradical pathways, Fe-TCPP/PMS demonstrates a wide pH range of 3-10 and exhibits minimal sensitivity to interference of concomitant materials. BPS is primarily eliminated through β-scission and hydroxylation. Specifically, O electrophilically attacks the C-S bond of BPS, while high-valent iron-oxo species interacts with BPS through an oxygen-bound mechanism. This study provides novel insights into efficient activation of PMS by iron porphyrin, enabling the removal of refractory pollutants through nonradical pathway.
Topics: Ferric Compounds; Porphyrins; Environmental Pollutants; Peroxides; Iron; Oxygen
PubMed: 38043614
DOI: 10.1016/j.chemosphere.2023.140847 -
Cryo Letters 2023Cryopreservation of porcine oocytes is difficult compared with other species and immature oocytes particularly so compared to the meiotic stage.
BACKGROUND
Cryopreservation of porcine oocytes is difficult compared with other species and immature oocytes particularly so compared to the meiotic stage.
OBJECTIVE
To evaluate the efficacy of a pretreatment with 1 micromole per L paclitaxel (PTX, 30 min exposure) before vitrification to promote the maturation of porcine immature oocytes.
MATERIALS AND METHODS
Cumulus cell-enclosed oocytes (COs) aspirated from porcine ovaries were divided into three groups: i) non-pretreated with PTX and non-vitrified group (control group); ii) pretreated with PTX and vitrified group (PTX-V group); and iii) non-pretreated with PTX and vitrified group (nPTX-V group).
RESULTS
The nuclear maturation rate up to the preovulatory stage was significantly lower (P < 0.05) in the nPTX-V group than in the control group, but was similar in the PTX-V and control groups. No significant differences were observed in viability assessed by a normal CO morphology and the embryonic development of oocytes activated by the parthenogenetic stimulation between the PTX-V and control groups, but not the non-PTX-V group.
CONCLUSION
PTX may promote the maturation of vitrified porcine immature oocytes. Doi.org/10.54680/fr23510110812.
Topics: Female; Pregnancy; Swine; Animals; Vitrification; Cryopreservation; Oocytes; Embryonic Development; Paclitaxel
PubMed: 38032311
DOI: No ID Found