Intra-articular Injection of Kartogenin-Enhanced Bone Marrow-Derived Mesenchymal Stem Cells in the Treatment of Knee Osteoarthritis in a Rat Model.

BACKGROUND: In this study, we investigated the in vitro and in vivo chondrogenic capacity of kartogenin (KGN)-enhanced bone marrow-derived mesenchymal stem cells (BMSCs) for cartilage regeneration. PURPOSE: To determine (1) whether functionalized nanographene oxide (NGO) can effectively deliver KGN into BMSCs and (2) whether KGN would enhance BMSCs during chondrogenesis in vitro and in vivo in an animal model. STUDY DESIGN: Controlled laboratory study. METHODS: Functionalized NGO with line chain amine-terminated polyethylene glycol (PEG) and branched polyethylenimine (BPEI) were used to synthesize biocompatible NGO-PEG-BPEI (PPG) and for loading hydrophobic KGN molecules noncovalently via π-π stacking and hydrophobic interactions (PPG-KGN). Then, PPG-KGN was used for the intracellular delivery of hydrophobic KGN by simple mixing and co-incubation with BMSCs to acquire KGN-enhanced BMSCs. The chondrogenic efficacy of KGN-enhanced BMSCs was evaluated in vitro. In vivo, osteoarthritis (OA) was induced by anterior cruciate ligament transection in rats. A total of 5 groups were established: normal (OA treated with nothing), phosphate-buffered saline (PBS; intra-articular injection of PBS), PPG-KGN (intra-articular injection of PPG-KGN), BMSCs (intra-articular injection of BMSCs), and BMSCs + PPG-KGN (intra-articular injection of PPG-KGN-preconditioned BMSCs). At 6 and 9 weeks after the surgical induction of OA, the rats received intra-articular injections of PPG-KGN, BMSCs, or KGN-enhanced BMSCs. At 14 weeks after the surgical induction of OA, radiographic and behavioral evaluations as well as histological analysis of the knee joints were performed. RESULTS: The in vitro study showed that PPG could be rapidly uptaken in the first 4 hours after incubation, reaching saturation at 12 hours and accumulating in the lysosome and cytoplasm of BMSCs. Thus, PPG-KGN could enhance the efficiency of the intracellular delivery of KGN, which showed a remarkably high chondrogenic differentiation capacity of BMSCs. When applied to an OA model of cartilage injuries in rats, PPG-KGN-preconditioned BMSCs contributed to protection from joint space narrowing, pathological mineralization, OA development, and OA-induced pain, as well as improved tissue regeneration, as evidenced by radiographic, weightbearing, and histological findings. CONCLUSION: Our results demonstrate that KGN-enhanced BMSCs showed markedly improved capacities for chondrogenesis and articular cartilage repair. We believe that this work demonstrates that a multifunctional nanoparticle-based drug delivery system could be beneficial for stem cell therapy. Our results present an opportunity to reverse the symptoms and pathophysiology of OA. CLINICAL RELEVANCE: The intracellular delivery of KGN to produce BMSCs with enhanced chondrogenic potential may offer a new approach for the treatment of OA.

Mitochondria-targeting graphene oxide nanocomposites for fluorescence imaging-guided synergistic phototherapy of drug-resistant osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is the most common primary malignant bone tumor occurring in children and young adults. Drug-resistant osteosarcoma often results in chemotherapy failure. Therefore, new treatments aimed at novel therapeutic targets are urgently needed for the treatment of drug-resistant osteosarcoma. Mitochondria-targeted phototherapy, i.e., synergistic photodynamic/photothermal therapy, has emerged as a highly promising strategy for treating drug-resistant tumors. This study proposed a new nano-drug delivery system based on near-infrared imaging and multifunctional graphene, which can target mitochondria and show synergistic phototherapy, with preferential accumulation in tumors. METHODS AND RESULTS: Based on our previous study, (4-carboxybutyl) triphenyl phosphonium bromide (TPP), a mitochondria-targeting ligand, was conjugated to indocyanine green (ICG)-loaded, polyethylenimine-modified PEGylated nanographene oxide sheets (TPP-PPG@ICG) to promote mitochondrial accumulation after cellular internalization. Thereafter, exposure to a single dose of near-infrared irradiation enabled synergistic photodynamic and photothermal therapy, which simultaneously inhibited adenosine triphosphate synthesis and mitochondrial function. Induction of intrinsic apoptosis assisted in surmounting drug resistance and caused tumor cell death. After fluorescence imaging-guided synergistic phototherapy, the mitochondria-targeting, multifunctional graphene-based, drug-delivery system showed highly selective anticancer efficiency in vitro and in vivo, resulting in marked inhibition of tumor progression without noticeable toxicity in mice bearing doxorubicin-resistant MG63 tumor cells. CONCLUSION: The mitochondria-targeting TPP-PPG@ICG nanocomposite constitutes a new class of nanomedicine for fluorescence imaging-guided synergistic phototherapy and shows promise for treating drug-resistant osteosarcoma.

Antibody responses to SARS-CoV-2 in patients with COVID-19.

We report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G (IgG). Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT-PCR results and for the identification of asymptomatic infections.

Hyperglycemia-induced inhibition of DJ-1 expression compromised the effectiveness of ischemic postconditioning cardioprotection in rats.

Ischemia postconditioning (IpostC) is an effective way to alleviate ischemia and reperfusion injury; however, the protective effects seem to be impaired in candidates with diabetes mellitus. To gain deep insight into this phenomenon, we explored the role of DJ-1, a novel oncogene, that may exhibit powerful antioxidant capacity in postconditioning cardioprotection in a rat model of myocardial ischemia reperfusion injury. Compared with normal group, cardiac DJ-1 was downregulated in diabetes. Larger postischemic infarct size as well as exaggeration of oxidative stress was observed, while IpostC reversed the above changes in normal but not in diabetic rats. DJ-1 was increased after ischemia and postconditioning contributed to a further elevation; however, no alteration of DJ-1 was documented in all subgroups of diabetic rats. Alteration of the cardioprotective PI3K/Akt signaling proteins may be responsible for the ineffectiveness of postconditioning in diabetes. There is a positive correlation relationship between p-Akt and DJ-1 but a negative correlation between infarct size and DJ-1, which may partially explain the interaction of DJ-1 and IpostC cardioprotection. Our result indicates a beneficial role of DJ-1 in myocardial ischemia reperfusion. Downregulation of cardiac DJ-1 may be responsible for the compromised diabetic heart responsiveness to IpostC cardioprotection.

Transient acidosis during early reperfusion attenuates myocardium ischemia reperfusion injury via PI3k-Akt-eNOS signaling pathway.

In this paper, we concluded that transient acidosis reperfusion conferred cardioprotection against myocardial ischemia reperfusion injury in isolated rat hearts through activating PI3K-Akt-eNOS pathway.

Nitroglycerine-induced nitrate tolerance compromises propofol protection of the endothelial cells against TNF-α: the role of PKC-ß2 and NADPH oxidase.

Continuous treatment with organic nitrates causes nitrate tolerance and endothelial dysfunction, which is involved with protein kinase C (PKC) signal pathway and NADPH oxidase activation. We determined whether chronic administration with nitroglycerine compromises the protective effects of propofol against tumor necrosis factor (TNF-) induced toxicity in endothelial cells by PKC- ß2 dependent NADPH oxidase activation. Primary cultured human umbilical vein endothelial cells were either treated or untreated with TNF- α (40 ng/mL) alone or in the presence of the specific PKC- ß2 inhibitor CGP53353 (1 µM)), nitroglycerine (10 µM), propofol (100 µM), propofol plus nitroglycerin, or CGP53353 plus nitroglycerine, respectively, for 24 hours. TNF-α increased the levels of superoxide, Nox (nitrate and nitrite), malondialdehyde, and nitrotyrosine production, accompanied by increased protein expression of p-PKC-ß2, gP91phox, and endothelial cell apoptosis, whereas all these changes were further enhanced by nitroglycerine. CGP53353 and propofol, respectively, reduced TNF-α induced oxidative stress and cell toxicity. CGP53353 completely prevented TNF- α induced oxidative stress and cell toxicity in the presence or absence of nitroglycerine, while the protective effects of propofol were neutralized by nitroglycerine. It is concluded that nitroglycerine comprises the protective effects of propofol against TNF-α stimulation in endothelial cells, primarily through PKC-ß2 dependent NADPH oxidase activation.

Enzymatically crosslinked collagen-mimetic dendrimers that promote integrin-targeted cell adhesion.

Collagen is made up of a diverse family of the extracellular matrices, most of which are generally found crosslinked in vivo. To more closely mimic the biological function of collagen, this work focuses on establishing a molecular strategy to engineer a functional biomimetic collagen that exhibits stable collagen-like triple-helical conformation with cell-binding activity, in addition to an enzyme-mediated crosslinking by tissue transglutaminase (tTGase). A novel sequence spanning residues 2800-2807 of human fibrillin-1 (EDGFFKI) was first identified as an amine donor substrate for tTGase, using a previously characterized APQQEA derived from human osteonectin as an amine acceptor probe. Subsequently, collagen-mimetic peptides (CMPs) supplemented with a cell-binding sequence (GFOGER) and the identified EDGFFKI and APQQEA substrate sequences were conjugated onto a generation 2 poly(amidoamine) dendrimer, resulting in a crosslinkable collagen-mimetic dendrimer, denoted as CMD-K and CMD-Q, respectively. Both CMD-K and CMD-Q exhibited enhanced triple-helical stability and supported cell adhesion in an integrin-specific manner. Finally, tTGase-mediated crosslinking between CMD-K and CMD-Q resulted in a supramolecular structure that exhibited stable collagen-like triple-helical conformation and improved cellular recognition. The results show that the triple-helical structure is important in preserving the GFOGER cell-binding site while the tTGase-mediated protein crosslinking may also be crucial for the recognition by cell surface integrin receptors.

[Effects of ferrous sulfate supplementation on bone marrow hemopoiesis in rats].

OBJECTIVE: To explore the influences of different dosage ferrous sulfate supplements on bone marrow hemopoiesis in rats. METHODS: Female weaning Wistar rats were fed with an iron deficient diet (< 10 mg/kg diet) until the level of hemoglobin of rats was lower than 100 g/L. Rats (n = 50) were randomly divided into five groups according to the levels of hemoglobin and body weight, iron deficiency control (ID), daily low iron diet supplement (LDs), daily high iron diet supplement (HDs), weekly low iron supplement (LWs), and weekly high iron supplement (HWs). RESULTS: After 12 weeks, bone marrow stainable iron was seldom in ID group, and ample in supplement groups. The proportions of iron staining of bone marrow smear in supplement groups were more than 30%. Bone marrow cells in all rats were hyperplastic or active hyperplastic. CONCLUSIONS: Daily high iron supplement or once weekly high iron supplement were safe to bone marrow hemopoiesis in rats.