Checkpoint blockade immunotherapy has emerged as a transformative approach in cancer treatment by activating tumor-infiltrating T cells. However, the efficacy of PD-L1 blockade is restricted in "cold" tumors, which are characterized by low immunogenicity, presenting a challenge to immunotherapy. This study introduces an innovative strategy, utilizing cathepsin-cleavable N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-assisted combined photodynamic therapy (PDT) and PD-L1 degradation for the first time, effectively treating T cell-deficient tumors. The degradable main-chain polymer, conjugated with photosensitizer porphyrin, facilitates the accumulation of reactive oxygen species (ROS), triggering immunogenic cell death (ICD) and promoting cytotoxic T lymphocytes (CTLs) infiltration into tumors. Multivalent peptide antagonists of PD-L1 promote PD-L1 degradation in lysosomes through receptor crosslinking, overcoming the adaptive cycling of PD-L1 to the tumor cell surface. These findings demonstrate that polymer-assisted PDT and PD-L1 crosslinking degradation represent a potential novel strategy for anti-tumor immunotherapy, providing valuable tools for expanding immunotherapy applications in immunosuppressive cancers.

The continuous emergence of SARS-CoV-2 variants as well as other potential future coronavirus has challenged the effectiveness of current COVID-19 vaccines. Therefore, there remains a need for alternative antivirals that target processes less susceptible to mutations, such as the formation of six-helix bundle (6-HB) during the viral fusion step of host cell entry. In this study, a novel high-throughput screening (HTS) assay employing a yeast-two-hybrid (Y2H) system was established to identify inhibitors of HR1/HR2 interaction. The compound IMB-9C, which achieved single-digit micromolar inhibition of SARS-CoV-2 and its Omicron variants with low cytotoxicity, was selected. IMB-9C effectively blocks the HR1/HR2 interaction in vitro and inhibits SARS-CoV-2-S-mediated cell-cell fusion. It binds to both HR1 and HR2 through non-covalent interaction and influences the secondary structure of HR1/HR2 complex. In addition, virtual docking and site-mutagenesis results suggest that amino acid residues A930, I931, K933, T941, and L945 are critical for IMB-9C binding to HR1. Collectively, in this study, we have developed a novel screening method for HR1/HR2 interaction inhibitors and identified IMB-9C as a potential antiviral small molecule against COVID-19 and its variants.

Sigma-1 receptor (σ ₁R) has become a focus point of drug discovery for central nervous system (CNS) diseases. A series of novel 1-phenylethan-1-one O-(2-aminoethyl) oxime derivatives were synthesized. In vitro biological evaluation led to the identification of 1a, 14a, 15d and 16d as the most high-affinity (K _i < 4 nmol/L) and selective σ ₁R agonists. Among these, 15d, the most metabolically stable derivative exhibited high selectivity for σ ₁R in relation to σ ₂R and 52 other human targets. In addition to low CYP450 inhibition and induction, 15d also exhibited high brain permeability and excellent oral bioavailability. Importantly, 15d demonstrated effective antipsychotic potency, particularly for alleviating negative symptoms and improving cognitive impairment in experimental animal models, both of which are major challenges for schizophrenia treatment. Moreover, 15d produced no significant extrapyramidal symptoms, exhibiting superior pharmacological profiles in relation to current antipsychotic drugs. Mechanistically, 15d inhibited GSK3β and enhanced prefrontal BDNF expression and excitatory synaptic transmission in pyramidal neurons. Collectively, these in vivo proof-of-concept findings provide substantial experimental evidence to demonstrate that modulating σ ₁R represents a potential new therapeutic approach for schizophrenia. The novel chemical entity along with its favorable drug-like and pharmacological profile of 15d renders it a promising candidate for treating schizophrenia.

OBJECTIVES: Through the investigation of the microhardness and microstructure of permanent tooth enamel at various eruption stages during childhood, this research offers references for the early prevention of childhood dental caries. METHODS: Forty-five premolars extracted due to orthodontic reasons were collected and screened. These premolars were divided into three experimental groups according to the time since eruption: Group A (erupted for 0-1 year), Group B (erupted for 1-3 years), and Group C (erupted for 3-5 years). Additionally, the third molars that were extracted due to impaction and had not erupted were selected as the control group, with 15 teeth in each group. Samples were prepared, and the surface microhardness, microstructure, and elemental composition of the enamel were measured using Vickers microhardness tester, scanning electron microscope, and electron probe, respectively. RESULTS: Compared with that in the control group, the microhardness of enamel in groups A, B, and C increased with prolonged eruption time, the surface porosity structure decreased considerably, the contents of Na and Mg on the surface decreased, and that of F increased (P<0.05). CONCLUSIONS The microhardness and microstructure of enamel in permanent teeth at different stages vary. Permanent teeth are at a substantially higher risk of caries within one year after eruption, and early prevention should be emphasized.
Dental Enamel/ultrastructure* ; Humans ; Hardness ; Dental Caries/prevention & control* ; Microscopy, Electron, Scanning ; Tooth Eruption ; Bicuspid/chemistry* ; Dentition, Permanent ; Child ; Child, Preschool

S-methyl-L-cysteine sulfoxide (SMCO) is a non-protein sulfur-containing amino acid with a variety of functions. There are few reports on the enzymes catalyzing the biosynthesis of SMCO from S-methyl-L-cysteine (SMC). In this study, the flavin-containing monooxygenase gene derived from Schizosaccharomyces pombe (spfmo) was heterologously expressed in Escherichia coli BL21(DE3) and the enzymatic properties of the expressed protein were analyzed. The optimum catalytic conditions of the recombinant SpFMO were 30 ℃ and pH 8.0, under which the enzyme activity reached 72.77 U/g. An appropriate amount of Mg²⁺ improved the enzyme activity. The enzyme kinetic analysis showed that the K_m and k_cat/K_m of SpFMO on the substrate SMC were 23.89 μmol/L and 61.71 L/(min·mmol), respectively. Under the optimal reaction conditions, the yield of SMCO synthesized from SMC catalyzed by SpFMO was 12.31% within 9 h. This study provides reference for the enzymatic synthesis of SMCO.
Schizosaccharomyces/genetics* ; Escherichia coli/metabolism* ; Recombinant Proteins/metabolism* ; Cysteine/biosynthesis* ; Mixed Function Oxygenases/metabolism* ; Schizosaccharomyces pombe Proteins/metabolism* ; Oxygenases/metabolism* ; Kinetics

Objective To explore the correlation of serum Chemerin level with disease activity and the ratio of T helper 17/regulatory T cells(Th17/Treg)in patients with rheumatoid arthritis(RA).Methods A total of 180 patients with RA who were admitted to our hospital were regarded as the observation group.According to the DAS28 score,the observation group was divided into the high activity group(60 cases),the moderate activity group(60 cases)and the low activity group(60 cases).Another 180 healthy people who underwent physical examination in our hospital during the same period were regarded as the control group.Enzyme-linked immunosorbent assay(ELISA)was used to detect serum levels of Chemerin,interleukin-9(IL-9),interleukin-10(IL-10)and interleukin-17(IL-17).Flow cytometry was used to detect the Th17/Treg ratio.Spearman correlation analysis was applied to analyze the correlation between serum Chemerin level and DAS28 score.Pearson correlation analysis was used to analyze the correlation between serum Chemerin level and Th17,Treg cell percentage and Th17/Treg ratio.Results The results of this study showed that the serum level of Chemerin was higher in the observation group than that in the control group(P＜0.05).The serum Chemerin level was positively correlated with DAS28 score(P＜0.05).Serum Chemerin levels and DAS28 scores decreased in turn in the high,moderate and low activity groups(P＜0.05).The percentage of Th17 cells and the ratio of Th17/Treg were higher in the observation group than those in the control group,and the percentage of Treg cells was lower in the observation group than that in the control group(P＜0.05).The level of IL-10 was lower in the observation group than that in the control group,while levels of IL-17 and IL-9 were higher in the observation group than those in the control group(P＜0.05).The results of Pearson correlation analysis showed that serum Chemerin level was positively correlated with the percentage of Th17 cells and the ratio of Th17/Treg,and negatively correlated with the percentage of Treg cells(P＜0.05).Conclusion Serum Chemerin level is elevated in patients with RA,which is closely related to disease activity and Th17/Treg ratio.

Background The senescence of alveolar type II epithelial cells is an important driving factor for the progression of silicotic fibrosis, and the regulatory effects of oxamate on the senescence of alveolar type II epithelial cells is still unclear. Objective To explore whether lactate dehydrogenase inhibitor oxamate can alleviate silicotic fibrosis in mice by inhibiting senescence of alveolar type II epithelial cellsMethods This study was divided into two parts: in vivo experiments and in vitro experiments. In the first part, forty SPF C57BL/6J male mice were randomly divided into four groups with 10 in each group: control group, silicosis model group, low-dose oxamate treatment group, and high-dose oxamate treatment group. The silicotic mouse model was established by intratracheal instillation of 50 μL SiO₂ suspension (100 mg·mL⁻¹). The treatment models were prepared by intraperitoneal injection of 100 μL oxamate (225 mmol·L⁻¹ and 1125 mmol·L⁻¹). In the second part, induction of MLE-12 mouse alveolar type II epithelial cells was conducted with SiO₂. The in vitro experimental groups were ① SiO₂ induction groups: control group, 50 μg·mL⁻¹ SiO₂ group, 100 μg·mL⁻¹ SiO₂ group, and 200 μg·mL⁻¹ SiO₂ group, and ② oxamate treatment groups: control group, SiO₂ group (100 μg·mL⁻¹), low-dose oxamate (25 mmol·L⁻¹) treatment group, and high-dose oxamate (50 mmol·L⁻¹) treatment group. Pathological morphology of lung tissues was evaluated after hematoxylin-eosin (HE) staining; deposition of collagen in lung tissues was evaluated after sirius red staining; positive co-expression of prosurfactant protein C (Pro-SPC) and β-galactosidase was detected by immunofluorescence staining; positive expression of β-galactosidase in MLE-12 cells was detected by immunofluorescence staining. The protein expression levels of collagen type I (CoL I), fibronectin1 (FN1), hexokinase 2 (HK2), pyruvate kinase isozyme type M2 (PKM2), lactate dehydrogenase A (LDHA), p-ataxia telangiectasia and Rad3-related kinase (ATR), and cyclin-dependent kinase inhibitors p21, and p16 were detected by Western blotting. Results Compared with the control group, the protein expression levels of HK2, PKM2, LDHA, p-ATR, p21, and p16 were significantly upregulated in the silicosis model group and the SiO₂-induced MLE-12 cells (P＜0.05). The in vivo studies showed that, compared with the control group, the silicon nodule area, the collagen deposition area, the proportion of β-galactosidase positive cells, and the protein expression levels of CoL I, FN1, LDHA, p-ATR, p21, and p16 were significantly upregulated in the silicosis model group (P＜0.05). Compared with the silicosis model group, the oxamate treatment groups showed significant downregulation of the silicon nodule area, the collagen deposition area, the proportion of β-galactosidase positive cells, and the the CoL I, FN1, LDHA, p-ATR, p21, and p16 protein expression levels, and the high-dose oxamate treatment group showed a higher efficacy on these indicators than the low-dose oxamate treatment group (P＜0.05). The in vitro studies showed that, compared with the control group, the proportion of β-galactosidase positive cells and the protein expression levels of p-ATR, p21, and p16 were significantly upregulated in the SiO₂-induced group (P＜0.05). Compared with the SiO₂ group, the proportion of β-galactosidase positive cells and the LDHA, p-ATR, p21 and p16 protein expression levels were significantly downregulated in the oxamate treatment groups, and the high-dose oxamate treatment group showed a higher efficacy on these indicators than the low-dose oxamate treatment group (P＜0.05). Conclusion Lactate dehydrogenase inhibitor oxamate can alleviate silicotic fibrosis in mice by inhibiting the senescence of alveolar type II epithelial cells.

OBJECTIVE To compare the anti-oxidative effects of "three decoctions for COVID-19" (Qingfei Paidu decoction, Huashi Baidu decoction, Xuanfei Baidu decoction) in parallel experimental models. METHODS In the cell-free system, the total antioxidant capacity was investigated by FRAP method. The scavenging effects of DPPH radicals and superoxide anions were evaluated by DPPH and NBT reduction method, respectively. The scavenging effect of hydroxyl radicals was determined by a fluorescence method based on the end-product MDA. The anti-lipid peroxidation activity was investigated using the FeSO4-induced rat liver homogenate MDA method. Based on these five antioxidant indicators, the antioxidant capabilities of the extracts of three decoctions were parallelly compared in the cell-free system. Furthermore, in lipopolysaccharide-activated RAW264.7 cells, the productions of intracellular and mitochondrial reactive oxygen species(ROS) were detected using the L-012 probe and the MitoSOX mitochondrial superoxide red fluorescence probe, respectively; and intracellular NADPH oxidase activity was measured using the lucigenin probe. These three indicators were used to parallelly compare the antioxidant capabilities of the extracts of three decoctions. RESULTS In the cell-free system, three decoctions for COVID-19 could concentration-dependently scavenge DPPH radicals, superoxide anions and hydroxyl radicals, and potently inhibit the lipid peroxidation. At the equal extract concentration, their scavenging effects on DPPH radicals and superoxide anions and the total antioxidant capacity were comparable; while Huashi Baidu decoction exhibited the strongest ability to scavenge hydroxyl radicals and inhibit lipid peroxidation. In the cell system, three decoctions could reduce lipopolysaccharide-elevated intracellular ROS level by weakening NADPH oxidase activity; meanwhile, they could decrease mitochondrial ROS productions, among which Qingfei Paidu decoction possessed the most comprehensive effection. CONCLUSION Collectively, three decoctions for COVID-19 exert diverse antioxidant effects in both cell-free and cell systems, and each of them possesses the distinct advantages. Given that oxidative stress is pivotal during the pathological process of COVID-19, the results may suggest that the antioxidant ability of three decoctions is one of the pharmacodynamic basis for their clinical use.

Objective: To clarify the specific mechanisms of action of raw Phellodendron chinense Schneid. (RPC) and saltwater-processed PC (SPC) in the treatment of rats with a kidney-yin deficiency pattern (KYDP). Methods: Healthy rats were administered hydrocortisone to establish a KYDP model. The rats were divided into seven groups: blank control, model, positive control (Liuwei Dihuang pills), high-dose RPC, low-dose RPC, high-dose SPC, and low-dose SPC. Enzyme-linked immunosorbent assay was used to measure the levels of cAMP, cGMP, TRH, TSH, T3, T4, IFN-γ, TNF-α, and testosterone in the serum and the levels of Na+-K+-ATPase and Ca2+-Mg2+-ATPase in the liver. TRH mRNA expression in the rat hypothalamus was measured using RT-PCR. THRα1+2 protein expression in the hypothalamus of rats was measured using Western blot. Immunohistochemistry was performed to determine the expression levels of FAS, FasL, and TSHR. Flow cytometry was used to determine CD4+ and CD8+ T lymphocyte levels. Illumina MiSeq sequencing technology was used to evaluate the diversity of intestinal flora in KYDP rats. Results: The cAMP/cGMP ratio was significantly higher in the model group than in the blank control group (P = .048). Compared with the model group, after administration, the levels of the above-mentioned serum and liver indexes decreased, except that of testosterone. The CD4+/CD8+ ratio also decreased. Compared with the RPC group, the levels of T3, IFN-γ, FAS, FasL, and TSHR in the SPC group decreased whereas that of testosterone increased. Additionally, immune function and intestinal flora diversity improved in the SPC group. SPC proved to be more effective in improving liver energy metabolism in KYDP rats than RPC. Conclusion SPC had a better therapeutic effect on KYDP than RPC. The underlying mechanism of action may be related to improvements in liver energy metabolism, immune function, and intestinal flora diversity.

ObjectiveA rapid method for identification of chemical constituents in Baoyuantang reference sample was established in order to clarify the material basis of this formula. MethodBased on ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS/MS） and self-established database information， the chemical components in Baoyuantang were systematically characterized and identified. The chromatography was performed on a Waters ACQUITY UPLC HSS T3 column（2.1 mm×100 mm， 1.8 μm） with mobile phase of 0.1% formic acid aqueous solution（A）-0.1% formic acid acetonitrile solution（B） for gradient elution（0-3 min， 2%-19%B； 3-8 min， 19%B； 8-8.1 min， 19%-22%B； 8.1-14 min， 22%-29%B； 14-16 min， 29%B； 16-32 min， 29%-45%B； 32-32.1 min， 45%-90%B； 32.1-35 min， 90%-95%B； 35-36 min， 95%-98%B； 36-37 min， 98%-2%B； 37-40 min， 2%B）. Based on electrospray ionization（ESI）， continuum data format was collected in both positive and negative ion modes with a scanning range of m/z 50-1 500. Chemical constituents in the decoction of Baoyuantang were systematically analyzed by UNIFI 1.9.4 software matching， control comparison， The Encyclopedia of Traditional Chinese Medicine（ETCM） database search and literature reports. ResultA total of 229 components were identified under negative ion mode and 181 under positive ion mode， with a total of 322 components after removing duplicates， including 116 triterpene saponins， 66 flavonoids， 19 organic acids， 6 gingerphenols， 6 gingerols， 5 gingerones， 10 amino acids， 7 saccharides， 5 coumarins and 82 other components. Among them， 83， 141， 39， 35 and 38 components were attributed to Ginseng Radix et Rhizoma， Glycyrrhizae Radix et Rhizoma， Astragali Radix， Cinnamomi Cortex and Zingiberis Rhizoma Recens， respectively. ConclusionIn this study， the rapid characterization and identification of multi-class components in Baoyuantang was realized， and it was confirmed that the material basis of this formula was mainly triterpenoid saponins， flavonoids， gingerols and organic acids， and the chemical composition was attributed and analyzed， which provided a reference for the subsequent quality control research.