Fragment-based Drug Discovery Strategy and its Application to the Design of SARS-CoV-2 Main Protease Inhibitor.

Severe Acute Respiratory Syndrome Coronavirus Type 2 (SARS-CoV-2) emerged at the end of 2019, causing a highly infectious and pathogenic disease known as 2019 coronavirus disease. This disease poses a serious threat to human health and public safety. The SARS-CoV-2 main protease (Mpro) is a highly sought-after target for developing drugs against COVID-19 due to its exceptional specificity. Its crystal structure has been extensively documented. Numerous strategies have been employed in the investigation of Mpro inhibitors. This paper is primarily concerned with Fragment-based Drug Discovery (FBDD), which has emerged as an effective approach to drug design in recent times. Here, we summarize the research on the approach of FBDD and its application in developing inhibitors for SARS-CoV-2 Mpro.

Ameliorative effect of salidroside on the cyclophosphamide-induced premature ovarian failure in a rat model.

BACKGROUND: Oxidative stress injury is an important pathological factor of premature ovarian failure (POF). Salidroside, extracted from the Chinese herb-Rhodiola rosea, has advantages in antioxidant characteristics. However, their therapeutic efficacy and mechanisms in POF have not been explored. PURPOSE: This study aims to assess the therapeutic effects of salidroside in chemotherapy-induced ovarian failure rats. METHODS: A POF rat model was established by injection of cyclophosphamide, followed by treatment with salidroside. The therapeutic effect of salidroside was evaluated based on hormone levels, follicle count, and reproductive ability. Oxidative stress injury was assessed by the detection of SOD enzyme activity and MDA levels. Differential gene expression of Keap1, Nrf2, HMOX1, NQO1, AMH, BMP15, and GDF9, were identified by qRT­PCR. The protein expression of Keap1, Nrf2, P53, and Bcl-2 were detected by western blot. RESULTS: Salidroside treatment markedly restored FSH, E2, and AMH hormone secretion levels, reduced follicular atresia, and increased antral follicle numbers in POF rats. In addition, salidroside improves fertility in POF rats, activates the Nrf2 signaling pathway, and reduces the level of oxidative stress. The recovery function of high dose salidroside (50 mg/kg) in a reproductive assay was significantly improved than that of lower dose salidroside (25 mg/kg). Meanwhile, the safety evaluation of salidroside treatment in rats showed that salidroside was safe for POF rats at doses of 25-50 mg/kg. CONCLUSIONS: Salidroside therapy improved premature ovarian failure significantly through antioxidant function and activating Nrf2 signaling.

Image-Guided Photothermal and Immune Therapy of Tumors via Melanin-Producing Genetically Engineered Bacteria.

Photothermal therapy (PTT) is a new treatment modality for tumors. However, the efficient delivery of photothermal agents into tumors remains difficult, especially in hypoxic tumor regions. In this study, an approach to deliver melanin, a natural photothermal agent, into tumors using genetically engineered bacteria for image-guided photothermal and immune therapy is developed. An Escherichia coli MG1655 is transformed with a recombinant plasmid harboring a tyrosinase gene to produce melanin nanoparticles. Melanin-producing genetically engineered bacteria (MG1655-M) are systemically administered to 4T1 tumor-bearing mice. The tumor-targeting properties of MG1655-M in the hypoxic environment integrate the properties of hypoxia targeting, photoacoustic imaging, and photothermal therapeutic agents in an "all-in-one" manner. This eliminates the need for post-modification to achieve image-guided hypoxia-targeted cancer photothermal therapy. Tumor growth is significantly suppressed by irradiating the tumor with an 808 nm laser. Furthermore, strong antitumor immunity is triggered by PTT, thereby producing long-term immune memory effects that effectively inhibit tumor metastasis and recurrence. This work proposes a new photothermal and immune therapy guided by an "all-in-one" melanin-producing genetically engineered bacteria, which can offer broad potential applications in cancer treatment.

Size-Based Microfluidic-Enriched Mesenchymal Stem Cell Subpopulations Enhance Articular Cartilage Repair.

BACKGROUND: The functional heterogeneity of culture-expanded mesenchymal stem cells (MSCs) has hindered the clinical application of MSCs. Previous studies have shown that MSC subpopulations with superior chondrogenic capacity can be isolated using a spiral microfluidic device based on the principle of inertial cell focusing. HYPOTHESIS: The delivery of microfluidic-enriched chondrogenic MSCs that are consistent in size and function will overcome the challenge of the functional heterogeneity of expanded MSCs and will significantly improve MSC-based cartilage repair. STUDY DESIGN: Controlled laboratory study. METHODS: A next-generation, fully automated multidimensional double spiral microfluidic device was designed to provide more refined and efficient isolation of MSC subpopulations based on size. Analysis of in vitro chondrogenic potential and RNA sequencing was performed on size-sorted MSC subpopulations. In vivo cartilage repair efficacy was demonstrated in an osteochondral injury model in 12-week-old rats. Defects were implanted with MSC subpopulations (n = 6 per group) and compared with those implanted with unsegregated MSCs (n = 6). Osteochondral repair was assessed at 6 and 12 weeks after surgery by histological, micro-computed tomography, and mechanical analysis. RESULTS: A chondrogenic MSC subpopulation was efficiently isolated using the multidimensional double spiral device. RNA sequencing revealed distinct transcriptomic profiles and identified differential gene expression between subpopulations. The delivery of a chondrogenic MSC subpopulation resulted in improved cartilage repair, as indicated by histological scoring, the compression modulus, and micro-computed tomography of the subchondral bone. CONCLUSION: We have established a rapid, label-free, and reliable microfluidic protocol for more efficient size-based enrichment of a chondrogenic MSC subpopulation. Our proof-of-concept in vivo study demonstrates the enhanced cartilage repair efficacy of these enriched chondrogenic MSCs. CLINICAL RELEVANCE: The delivery of microfluidic-enriched chondrogenic MSCs that are consistent in size and function can overcome the challenge of the functional heterogeneity of expanded MSCs, resulting in significant improvement in MSC-based cartilage repair. The availability of such rapid, label-free enriched chondrogenic MSCs can enable better cell therapy products for cartilage repair with improved treatment outcomes.

Spatial attention modulates multisensory integration: The dissociation between exogenous and endogenous orienting.

Previous studies have separately found that exogenous orienting decreases multisensory integration (MSI), while endogenous orienting enhances MSI. It is currently unclear, however, why the two orientations have opposite effects on MSI. In the current study, we investigated the interaction between spatial attention and MSI in two experiments based on the cue-target paradigm. Experiment 1 separated exogenous and endogenous orienting to investigate the effect of spatial attention on MSI by varying the predictability of the cue. Experiment 2 further explored the effect of endogenous orienting on MSI. We found that exogenous orienting induced by the directionality of the cue decreased MSI, while endogenous orienting induced by the predictability of the cue enhanced MSI. The role of spatial orienting need and spatial attention bias in the modulation of MSI by exogenous and endogenous orienting was discussed. The present study sheds new light on how spatial attention modulates MSI processes.

Configuration-mediated excited-state energy dissipation in metal-bridged dimeric D-A fluorophores for enhanced photothermal therapy.

Photothermal agents (PTAs) based on donor (D)-acceptor (A) NIR fluorophores show great promise in photothermal therapy due to their accessible molecular engineering to mediate excitation energy for high photothermal conversion. Except for molecular structural modification of D-A fluorophores, intermolecular arrangement in space greatly influences their excitation energy dissipation as well. But how to mediate their intermolecular arrangement is still challenging. Here we control the intermolecular orientation of chromophores via metal coordination to form Pt-bridged dimeric D-A fluorophores with different geometries. The formed configuration isomers show different intermolecular exciton coupling behaviors involving charge transfer (CT) evolution and internally limited molecular rotation, which greatly affect excited-energy dissipation. Compared with folded configuration with intense NIR emission (quantum yields (QYs) = 15.62 %), linear configuration favors non-radiative decays with low QYs (6.99 %) but enhanced photothermal conversion efficiency (PCE = 41.57 %). The self-assembled nanoparticles combining Pt-bridged dimeric D-A fluorophores with DSPE-PEG2000-RGD reveal superior photothermal therapeutic features with desirable biosafety. This research provides a new designing concept to mediate excited-state energy dissipation pathways at a sub-nano level for enhanced photothermal conversion. STATEMENT OF SIGNIFICANCE: D-A fluorophores as photothermal agents attract great attention in photothermal therapy due to their accessible molecular engineering. Besides molecular engineering of D-A fluorophores, the intermolecular packing manner is proven to greatly affect their excitation energy dissipation. But how to control intermolecular arrangement is still challenging. Here we control the intermolecular orientation of chromophores via metal coordination to form Pt-bridged dimeric D-A fluorophores with different geometries. Compared to the folded configuration, linear configuration facilitates charge transfer (CT) evolution and molecular rotation, which promotes non-radiative decays of excited energy for enhanced photothermal therapy.

Small molecule inhibitors against the bacterial pathogen Brucella.

Brucellosis remains one of the major zoonotic diseases worldwide. As a causative agent of brucellosis, it has many ways to evade recognition by the immune system, allowing it to replicate and multiply in the host, causing significant harm to both humans and animals. The pathogenic mechanism of Brucella has not been elucidated, making the identification of drug targets from the pathogenic mechanism a challenge. Metalloenzymatic targets and some protein targets unique to Brucella are exploitable in the development of inhibitors against this disease. The development of specific small molecule inhibitors is urgently needed for brucellosis treatment due to the antibiotic resistance of Brucella. This review summarizes the research on small molecule inhibitors of Brucella, which could be instructive for subsequent studies.

GCKR and ADIPOQ gene polymorphisms in women with gestational diabetes mellitus.

AIMS: To investigate the associations of GCKR and ADIPOQ variants with the risk of gestational diabetes mellitus (GDM) in Chinese women. METHODS: GCKR rs1260326, ADIPOQ rs266729, and rs1501299 were selected and genotyped in 519 GDM patients and 498 controls. Candidate SNPs were genotyped using multiplex polymerase chain reaction (PCR) combined with next-generation sequencing methods, and the association of these SNPs with GDM was analyzed. RESULTS: We found that GCKR rs1260326 was significantly associated with an increased risk of GDM in the allele model, the codominant model (CC vs. TT), the dominant model, the recessive model, and the genotypic model distributions (p = 0.0029, p = 0.0022, p = 0.0402, p = 0.0038, and p = 0.0028, respectively). The rs1260326 polymorphism was shown to be associated with 1 h-OGTT level and gravidity in GDM patients (CC vs. TT: p = 0.0475 and p = 0.0220, respectively). Diastolic blood pressure (DBP) was significantly higher in the GDM patients with the rs266729 GG genotype compared to those with the CC or CG genotype (p = 0.0444 and p = 0.0339, respectively). The DBP of the GDM patients with the rs1501299 GT genotype was lower than that of those with the GG genotype (p = 0.0197). There was a weak linkage disequilibrium value between the GCKR and ADIPOQ SNPs. CONCLUSIONS: The genes GCKR and ADIPOQ may be involved in the pathophysiology of GDM.

Integration of Activation by Hypoxia and Inhibition Resistance of Tumor Cells to Apoptosis for Precise and Augmented Photodynamic Therapy.

Photodynamic therapy (PDT) uses photosensitizers to convert oxygen (O2 ) to reactive oxygen species (ROS) under irradiation to induce DNA damage and kill cancer cells. However, the effect of PDT is usually alleviated by apoptosis resistance mechanism of tumor living cells. MTH1 enzyme is known to be such an apoptosis-resistance enzyme which is over expressed as a scavenger to repair the damaged DNA. In this work, a hypoxia-activated nanosystem FTPA, which can be degraded to release the encapsulated PDT photosensitizer 4-DCF-MPYM and an inhibitor TH588 is proposed. The inhibitor TH588 can inhibit the DNA repair process by reducing the activity of MTH1 enzyme, and achieve the purpose of amplifying the therapeutic effect of PDT. This work demonstrates that a precise and augmented tumor PDT is achieved by integration of hypoxia-activation and inhibition resistance of tumor cells to apoptosis.

Secretive derived from hypoxia preconditioned mesenchymal stem cells promote cartilage regeneration and mitigate joint inflammation via extracellular vesicles.

Secretome derived from mesenchymal stem cells (MSCs) have profound effects on tissue regeneration, which could become the basis of future MSCs therapies. Hypoxia, as the physiologic environment of MSCs, has great potential to enhance MSCs paracrine therapeutic effect. In our study, the paracrine effects of secretome derived from MSCs preconditioned in normoxia and hypoxia was compared through both in vitro functional assays and an in vivo rat osteochondral defect model. Specifically, the paracrine effect of total EVs were compared to that of soluble factors to characterize the predominant active components in the hypoxic secretome. We demonstrated that hypoxia conditioned medium, as well as the corresponding EVs, at a relatively low dosage, were efficient in promoting the repair of critical-sized osteochondral defects and mitigated the joint inflammation in a rat osteochondral defect model, relative to their normoxia counterpart. In vitro functional test shows enhancement through chondrocyte proliferation, migration, and matrix deposition, while inhibit IL-1ß-induced chondrocytes senescence, inflammation, matrix degradation, and pro-inflammatory macrophage activity. Multiple functional proteins, as well as a change in EVs' size profile, with enrichment of specific EV-miRNAs were detected with hypoxia preconditioning, implicating complex molecular pathways involved in hypoxia pre-conditioned MSCs secretome generated cartilage regeneration.

Predictive value of bile acids as metabolite biomarkers for gallstones: A protocol of systematic review and meta-analysis.

BACKGROUND: Plenty of studies have focused on the bile acids profile in gallstones. The objective of our systematic review is to provide a comprehensive summary about bile acids profiles in gallstones and analyzes the difference between gallstones and control group in diverse samples, determining the characteristic bile acids as the metabolite biomarkers for predicting gallstone. METHODS: EMBASE, the Cochrane Library, PubMed, Web of Science, Wanfang databases, China National Knowledge Infrastructure (CNKI), VIP Information Resource Integration Service Platform (CQVIP), and China Biology Medicine Disc (SinoMed) will be searched with the keywords of gallstones and metabolomics. The screening process will be performed strictly according to inclusion and exclusion criteria. The CONSORT checklist and the Newcastle-Ottawa Scale (NOS) will assess the risk of bias for randomized controlled trials and observational studies, respectively. The qualitative review will be conducted to summarize the bile acids profile in gallstones. The concentrations of bile acids in both case group and control group will be the primary outcomes to perform the meta-analyses. EXPECTED RESULTS: Our systematic review will find the characteristic bile acids as the candidate metabolite biomarkers which equipped potential value to predict gallstones. CONCLUSION: Expanding the current knowledge on the physiopathology of gallstones and identifying novel predictive biomarkers can help to facilitate the detection and management of gallstones. Consequently, we expect this protocol to be a reasonable method to filtrate candidate differential bile acids which have potential value to predict gallstones. PROSPERO REGISTRATION NUMBER: CRD42022339649.

Integration of TADF Photosensitizer as "Electron Pump" and BSA as "Electron Reservoir" for Boosting Type I Photodynamic Therapy.

Type I photosensitization provides an effective solution to the problem of unsatisfactory photodynamic therapeutic (PDT) effects caused by the tumor hypoxia. The challenge in the development of Type I mode is to boost the photosensitizer's own electron transfer capacity. Herein, we found that the use of bovine serum albumin (BSA) to encapsulate a thermally activated delayed fluorescence (TADF) photosensitizer PS can significantly promote the Type I PDT process to generate a mass of superoxide anions (O2•-). This Type I photosensitization opened a new strategy by employing BSA as "electron reservoir" and TADF photosensitizer as "electron pump". We integrated these roles of BSA and PS in one system by preparing nanophotosensitizer PS@BSA. The Type I PDT performance was demonstrated with tumor cells under hypoxic conditions. Furthermore, PS@BSA took full advantage of the tumor-targeting role of BSA and achieved efficient PDT for tumor-bearing mice in the in vivo experiments. This work provides an effective route to improve the PDT efficiency of hypoxic tumors.

Nomogram based on the O-RADS for predicting the malignancy risk of adnexal masses with complex ultrasound morphology.

OBJECTIVE: The accurate preoperative differentiation of benign and malignant adnexal masses, especially those with complex ultrasound morphology, remains a great challenge for junior sonographers. The purpose of this study was to develop and validate a nomogram based on the Ovarian-Adnexal Reporting and Data System (O-RADS) for predicting the malignancy risk of adnexal masses with complex ultrasound morphology. METHODS: A total of 243 patients with data on adnexal masses with complex ultrasound morphology from January 2019 to December 2020 were selected to establish the training cohort, while 106 patients with data from January 2021 to December 2021 served as the validation cohort. Univariate and multivariate analyses were used to determine independent risk factors for malignant tumors in the training cohort. Subsequently, a predictive nomogram model was developed and validated in the validation cohort. The calibration, discrimination, and clinical net benefit of the nomogram model were assessed separately by calibration curves, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA). Finally, we compared this model to the O-RADS. RESULTS: The O-RADS category, an elevated CA125 level, acoustic shadowing and a papillary projection with color Doppler flow were the independent predictors and were incorporated into the nomogram model. The area under the ROC curve (AUC) of the nomogram model was 0.958 (95% CI, 0.932-0.984) in the training cohort. The specificity and sensitivity were 0.939 and 0.893, respectively. This nomogram also showed good discrimination in the validation cohort (AUC = 0.940, 95% CI, 0.899-0.981), with a sensitivity of 0.915 and specificity of 0.797. In addition, the nomogram model showed good calibration efficiency in both the training and validation cohorts. DCA indicated that the nomogram was clinically useful. Furthermore, the nomogram model had higher AUC and net benefit than the O-RADS. CONCLUSION: The nomogram based on the O-RADS showed a good predictive ability for the malignancy risk of adnexal masses with complex ultrasound morphology and could provide help for junior sonographers.

Real-time Elastography and Contrast-Enhanced Ultrasound for Evaluating Adventitia in the Early Diagnosis of Vulnerable Plaques: an Exploratory Study Based on Histopathology.

Vulnerable plaque is closely related to the occurrence of ischemic stroke. Therefore, early accurate identification of plaque vulnerability is crucial in risk stratification. In the development of vulnerable plaques, the change of the adventitia is earlier than that of the intima. Currently, researchers focused on the ultrasound detection of intraplaque and intima, but adventitia was often ignored in the examination. Real-time elastography technology (RTE) provides an estimation of adventitia stiffness, and contrast-enhanced ultrasound (CEUS) provides the quantification of adventitial VV. Therefore, we aimed to evaluate the value of adventitia in the early diagnosis of plaque vulnerability by combining CEUS and RTE based on histopathology. Rabbit carotid atherosclerosis models were established, and CEUS and RTE were performed. Normalized maximal video-intensity enhancement (MVE) was calculated to quantify adventitial VV density, and strain values were acquired to evaluate the adventitial elasticity. After removal of the lesion lumen, histological analysis of each excised plaque and adventitia was performed, and vulnerable plaques (n = 32) and stable group (n = 13) were distinguished. Normalized MVE of the adventitial VV and adventitial strain values in the vulnerable group was significantly higher than those in the stable group. Normalized MVE and strain values had a positive linear correlation with histological findings. Normalized MVE of the adventitial VV combined with adventitial strain values could identify plaque vulnerability with the area under the curve of 0.913 (sensitivity 90% and specificity 97%). Accordingly, the multimodal ultrasound detection strategy of adventitia has a high diagnostic value for early plaque vulnerability.

An injectable gelatin/sericin hydrogel loaded with human umbilical cord mesenchymal stem cells for the treatment of uterine injury.

Abnormal endometrial receptivity is a major cause of the failure of embryo transplantation, which may lead to infertility, adverse pregnancy, and neonatal outcomes. While hormonal treatment has dramatically improved the fertility outcomes in women with endometriosis, a substantial unmet need persists in the treatment. In this study, methacrylate gelatin (GelMA) and methacrylate sericin (SerMA) hydrogel with human umbilical cord mesenchymal stem cells (HUMSC) encapsulation was designed for facilitating endometrial regeneration and fertility restoration through in situ injection. The presented GelMA/10%SerMA hydrogel showed appropriate swelling ratio, good mechanical properties, and degradation stability. In vitro cell experiments showed that the prepared hydrogels had excellent biocompatibility and cell encapsulation ability of HUMSC. Further in vivo experiments demonstrated that GelMA/SerMA@HUMSC hydrogel could increase the thickness of endometrium and improve the endometrial interstitial fibrosis. Moreover, regenerated endometrial tissue was more receptive to transfer embryos. Summary, we believed that GelMA/SerMA@HUMSC hydrogel will hold tremendous promise to repair or regenerate damaged endometrium.

Modal-based attention modulates the redundant-signals effect: Role of unimodal target probability.

Multisensory integration includes two behavioral manifestations: the modality dominance effect and the redundant-signals effect (RSE). RSE is a multisensory improvement effect in which individuals respond more quickly and accurately to bimodal audiovisual (AV) targets than to unimodal auditory (A) or visual (V) targets. Previous studies have confirmed that RSE is the product of modality interactions between different modalities. The goal of this study was to systematically investigate the effects of the modality dominance manipulated by modal-based attention and unimodal target probability on RSE. The results showed that when paying attention to both the A and V modalities (Exp. 1), RSE was not significantly different between unimodal target probabilities. When selectively paying attention to the A modality (Exp. 2A), RSE was also not significantly different between unimodal target probabilities. However, when selectively paying attention to the V modality (Exp. 2B), the magnitude of RSE showed a significant decreasing trend with the increasing probability of V targets. Our study is the first to reveal that the unimodal target probability significantly modulates RSE in visual selective attention, and this modulatory effect of the unimodal target probability on RSE is opposite to the modulatory effect on the modality dominance effect.

LncmiRHG-MIR100HG: A new budding star in cancer.

MIR100HG, also known as lncRNA mir-100-let-7a-2-mir-125b-1 cluster host gene, is a new and critical regulator in cancers in recent years. MIR100HG is dysregulated in various cancers and plays an oncogenic or tumor-suppressive role, which participates in many tumor cell biology processes and cancer-related pathways. The errant expression of MIR100HG has inspired people to investigate the function of MIR100HG and its diagnostic and therapeutic potential in cancers. Many studies have indicated that dysregulated expression of MIR100HG is markedly correlated with poor prognosis and clinicopathological features. In this review, we will highlight the characteristics and introduce the role of MIR100HG in different cancers, and summarize the molecular mechanism, pathways, chemoresistance, and current research progress of MIR100HG in cancers. Furthermore, some open questions in this rapidly advancing field are proposed. These updates clarify our understanding of MIR100HG in cancers, which may pave the way for the application of MIR100HG-targeting approaches in future cancer diagnosis, prognosis, and therapy.

A Selenium-Substituted Heptamethine Cyanine Photosensitizer for Near-Infrared Photodynamic Therapy.

Photodynamic therapy (PDT) is a relatively safe approach to cancer treatment without significant systemic side effects or drug resistance. However, the current PDT efficiency is unsatisfactory due to the lack of near-infrared (NIR) photosensitizers. Heptamethine cyanine (Cy7) dyes are well-known NIR fluorophores and are also used as photosensitizers. But their singlet oxygen quantum yields (ΦΔ ) are not ideal. Herein, we developed an NIR photosensitizer with a long-lived excited triplet state (τ=4.3 µs) by introducing a selenium atom into the structure of a Cy7 dye. The new NIR photosensitizer exhibits a significantly high singlet oxygen quantum yield (ΦΔ =0.11). Its good PDT effect was demonstrated in the living cells. Considering that the selenium-substituted photosensitizer has a very low dark cytotoxicity and good chemical stability, we conclude that it will have a promising future in biomedical and clinical applications.

The co-influence of hyaluronic acid and collagen on the development of an engineered annulus tissue model with bone marrow stromal cells.

Inveterbral disc degeneration is a significant musculoskeletal disease that brings huge burden of pain, disability, psychological and social consequences to the affected population worldwide with treatments that only alleviate the pain but does not address the underlying biological problems. For the past decades, tissue engineering of the disc has been investigated with annulus fibrosus (AF) been one of the complicated disc component to be engineered. With the limited source of annulus cells, bone marrow stromal cells (BMSCs) have been frequently investigated as a potental cell candidate to develop an AF-like tissue which often require a multi-disciplinary effort to achieve. The extracellular matrix of AF is largely make up of collagen and proteoglycan which is still unclear how these matrix proteins could influence the BMSCs towards constructing a AF-like tissue. In this study, we adopted a coiled hydrogel microfiber that resembles the micro-architecture of the native AF tissue to encapsulate BMSCs and incorporated collagen type 1 and hyaluronic acid which later demonstrated that the co-presence of hyaluronic acid and collagen could potentially regulated AF-associated biomarkers and protease expression which are critical for later development of an engineered AF tissue construct.