Targeted photodynamic neutralization of SARS-CoV-2 mediated by singlet oxygen.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has been on a rampage for more than two years. Vaccines in combination with neutralizing antibodies (NAbs) against SARS-CoV-2 carry great hope in the treatment and final elimination of coronavirus disease 2019 (COVID-19). However, the relentless emergence of variants of concern (VOC), including the most recent Omicron variants, presses for novel measures to counter these variants that often show immune evasion. Hereby we developed a targeted photodynamic approach to neutralize SARS-CoV-2 by engineering a genetically encoded photosensitizer (SOPP3) to a diverse list of antibodies targeting the wild-type (WT) spike protein, including human antibodies isolated from a 2003 Severe acute respiratory syndrome (SARS) patient, potent monomeric and multimeric nanobodies targeting receptor-binding domain (RBD), and non-neutralizing antibodies (non-NAbs) targeting the more conserved N-terminal domain (NTD). As confirmed by pseudovirus neutralization assay, this targeted photodynamic approach significantly increased the efficacy of these antibodies, especially that of non-NAbs, against not only the WT but also the Delta strain and the heavily immune escape Omicron strain (BA.1). Subsequent measurement of infrared phosphorescence at 1270 nm confirmed the generation of singlet oxygen (1O2) in the photodynamic process. Mass spectroscopy assay uncovered amino acids in the spike protein targeted by 1O2. Impressively, Y145 and H146 form an oxidization "hotspot", which overlaps with the antigenic "supersite" in NTD. Taken together, our study established a targeted photodynamic approach against the SARS-CoV-2 virus and provided mechanistic insights into the photodynamic modification of protein molecules mediated by 1O2.

A novel distractor-assisted reduction combined with the sinus tarsi approach for joint depression-type calcaneal fractures.

PURPOSE: A novel percutaneous distractor with the advantage of axial and direct distraction was designed for the minimally invasive treatment of calcaneal fractures. The purpose of this study was to investigate the clinical results and complications of a novel distractor combined with sinus tarsi approach (STA) in treatment of the joint depression-type of calcaneal fractures. METHODS: Fifty-four patients with the depression-type of calcaneal fractures (30 Sanders type II, 22 Sanders type III, 2 Sanders type IV) who were subjected to the novel distractor combined with STA were retrospectively assessed. Calcaneal height, width, and length; Bohler's angle; and the Gissane angle were evaluated pre-operatively and post-operatively. Clinical outcomes were assessed using the American Orthopedic Foot and Ankle Society (AOFAS) and visual analog scale (VAS) pain scores from the last follow-up. Complications were also recorded. RESULTS: Fifty-two patients achieved an average follow-up of 24.3 months (range 18 to 34 months), and two patients were lost to follow-up six months post-operatively. There was significant difference between pre-operative and post-operative calcaneal height, width, and length; Bohler's angle; and Gissane angle (p < 0.01), but no significant difference was detected between the post-operative and normal side Bohler's angle (p > 0.05). The AOFAS ankle and hind foot score was 88.4 ± 6.6, and the VAS score was 1.9 ± 0.7 at the last follow-up. Nine (17.3%) patients developed complications: One experienced skin necrosis and two had screws loosening; three patients developed early degenerative changes of the subtalar joint; two had no symptoms; one had light pain around the subtalar joint without medical treatment; complex regional pain syndrome (CRPS) developed in one patient after seven months post-operatively; and two developed transient ankle stiffness. CONCLUSION: The novel distractor combined with the STA effectively reconstructs the facet depression-type of calcaneal fractures (sanders type II and III) with minimal complications.

Anti-Inflammatory, Antioxidant, and Antifibrotic Effects of Gingival-Derived MSCs on Bleomycin-Induced Pulmonary Fibrosis in Mice.

BACKGROUND: Mesenchymal stem cell (MSC) intervention has been associated with lung protection. We attempted to determine whether mouse gingival-derived mesenchymal stem cells (GMSCs) could protect against bleomycin-induced pulmonary fibrosis. METHODS: Mice were divided into three groups: control (Con), bleomycin (Bl), and bleomycin + MSCs (Bl + MSCs). Mice were treated with 5 mg/kg bleomycin via transtracheal instillation to induce pulmonary fibrosis. We assessed the following parameters: histopathological severity of injury in the lung, liver, kidney, and aortic tissues; the degree of pulmonary fibrosis; pulmonary inflammation; pulmonary oedema; profibrotic factor levels in bronchoalveolar lavage fluid (BALF) and lung tissue; oxidative stress-related indicators and apoptotic index in lung tissue; and gene expression levels of IL-1ß, IL-8, TNF-α, lysophosphatidic acid (LPA), lysophosphatidic acid receptor 1 (LPA1), TGF-ß, matrix metalloproteinase 9 (MMP-9), neutrophil elastase (NE), MPO, and IL-10 in lung tissue. RESULTS: GMSC intervention attenuated bleomycin-induced pulmonary fibrosis, pulmonary inflammation, pulmonary oedema, and apoptosis. Bleomycin instillation notably increased expression levels of the IL-1ß, IL-8, TNF-α, LPA, LPA1, TGF-ß, MMP-9, NE, and MPO genes and attenuated expression levels of the IL-10 gene in lung tissue, and these effects were reversed by GMSC intervention. Bleomycin instillation notably upregulated MDA and MPO levels and downregulated GSH and SOD levels in lung tissue, and these effects were reversed by GMSC intervention. GMSC intervention prevented upregulation of neutrophil content in the lung, liver, and kidney tissues and the apoptotic index in lung tissue. CONCLUSIONS: GMSC intervention exhibits anti-inflammatory and antioxidant capacities. Deleterious accumulation of neutrophils, which is reduced by GMSC intervention, is a key component of bleomycin-induced pulmonary fibrosis. GMSC intervention impairs bleomycin-induced NE, MMP-9, LPA, APL1, and TGF-ß release.

Therapeutic Potential of Bama Pig Adipose-Derived Mesenchymal Stem Cells for the Treatment of Carbon Tetrachloride-Induced Liver Fibrosis.

OBJECTIVES: Liver fibrosis is inevitable in the healing process of liver injury. Liver fibrosis will develop into liver cirrhosis unless the damaging factors are removed. This study investigated the potential therapy of Bama pig adipose-derived mesenchymal stem cells in a carbon tetrachloride-induced liver fibrosis Institute of Cancer Research strain mice model. MATERIALS AND METHODS: Adipose-derived mesenchymal stem cells were injected intravenously into the tails of mice of the Institute of Cancer Research strain that had been treated with carbon tetrachloride for 4 weeks. Survival rate, migration, and proliferation of adipose-derived mesenchymal stem cells in the liver were observed by histochemistry, fluorescent labeling, and serological detection. RESULTS: At 1, 2, and 3 weeks after adipose-derived mesenchymal stem cell injection, liver fibrosis was significantly ameliorated. The injected adipose-derived mesenchymal stem cells had hepatic differentiation potential in vivo, and the survival rate of adipose-derived mesenchymal stem cells declined over time. CONCLUSIONS: The findings in this study confirmed that adipose-derived mesenchymal stem cells derived from the Bama pig can be used in the treatment of liver fibrosis, and the grafted adipose-derived mesenchy-mal stem cells can migrate, survive, and differentiate into hepatic cells in vivo.

Functional ß-Cell Differentiation of Small-Tail Han Sheep Pancreatic Mesenchymal Stem Cells and the Therapeutic Potential in Type 1 Diabetic Mice.

OBJECTIVES: This study aims to investigate the characteristics of sheep pancreatic mesenchymal stem cells (PSCs) and therapeutic potential of differentiated ß-like cells in streptozotocin-induced diabetic mice. METHODS: Pancreatic mesenchymal stem cells were isolated from 3- to 4-month-old sheep embryos, and their biological characteristics were explored. The function and therapeutic potential of differentiated ß-like insulin-producing cells were also investigated in vitro and in vivo. Differentiated cells were identified through dithizone staining and immunofluorescence staining. Insulin secretion was analyzed using an enzyme-linked immunosorbent assay kit. The preliminary therapeutic potential of induced ß-like cells in diabetic mice was detected by blood glucose and body weight. RESULTS: Primary PSCs were isolated and subcultured up to passage 36. Immunofluorescence staining presented PSC-expressed important markers such as Pdx1, Nkx6-1, Ngn3, and Nestin. Primary PSCs could be induced into functional pancreatic ß-like islet cells with a 3-step protocol. The induced ß-like islet cells could ameliorate blood glucose in diabetic mice. CONCLUSIONS: The method proposed for generating pancreatic islet ß cells provided a preliminary phenotypic investigation of induced cell treatment in diabetic mice, and also laid a foundation in the identification of pharmaceutical targets to treat insulin-dependent diabetes.

Integration of thermocouple microelectrode in the scanning electrochemical microscope at variable temperatures: simultaneous temperature and electrochemical imaging and its kinetic studies.

We describe herein a method for the simultaneous measurement of temperature and electrochemical signal with a new type of thermocouple microelectrode. The thermocouple microelectrode can be used not only as a thermometer but also as a scanning electrochemical microscope (SECM) tip in the reaction between tip-generated bromine and a heated Cu sample. The influence of temperature on the SECM imaging process and the related kinetic parameters have been studied, such as kinetic constant and activation energy.