Recombinant porcine myostatin propeptide generated by the Pichia pastoris elevates myoblast growth and ameliorates high-fat diet-induced glucose intolerance

Novel Coagulation Factor VIII Gene Therapy in a Mouse Model of Hemophilia A by Lipid-Coated Fe3O4 Nanoparticles

Hemophilia A is a bleeding disease caused by loss of coagulation factor VIII (FVIII) function. Although prophylactic FVIII infusion prevents abnormal bleeding, disability and joint damage in hemophilia patients are common. The cost of treatment is among the highest for a single disease, and the adverse effects of repeated infusion are still an issue that has not been addressed. In this study, we established a nonviral gene therapy strategy to treat FVIII knockout (FVIII KO) mice. A novel gene therapy approach was developed using dipalmitoylphosphatidylcholine formulated with iron oxide (DPPC-Fe₃O₄) to carry the B-domain-deleted (BDD)-FVIII plasmid, which was delivered into the FVIII KO mice via tail vein injection. Here, a liver-specific albumin promoter-driven BDD-FVIII plasmid was constructed, and the binding ability of circular DNA was confirmed to be more stable than that of linear DNA when combined with DPPC-Fe₃O₄ nanoparticles. The FVIII KO mice that received the DPPC-Fe₃O₄ plasmid complex were assessed by staining the ferric ion of DPPC-Fe₃O₄ nanoparticles with Prussian blue in liver tissue. The bleeding of the FVIII KO mice was improved in a few weeks, as shown by assessing the activated partial thromboplastin time (aPTT). Furthermore, no liver toxicity, thromboses, deaths, or persistent changes after nonviral gene therapy were found, as shown by serum liver indices and histopathology. The results suggest that this novel gene therapy can successfully improve hemostasis disorder in FVIII KO mice and might be a promising approach to treating hemophilia A patients in clinical settings.

Precise editing of myostatin signal peptide by CRISPR/Cas9 increases the muscle mass of Liang Guang Small Spotted pigs

Myostatin (MSTN), a member of the transforming growth factor-β superfamily, is a negative regulator of muscle growth and development. Disruption of the MSTN gene in various mammalian species markedly promotes muscle growth. Previous studies have mainly focused on the disruption of the MSTN peptide coding region in pigs but not on the modification of the signal peptide region. In this study, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) system was used to successfully introduce two mutations (PVD20H and GP19del) in the MSTN signal peptide region of the indigenous Chinese pig breed, Liang Guang Small Spotted pig. Both mutations in signal peptide increased the muscle mass without inhibiting the production of mature MSTN peptide in the cells. Histological analysis revealed that the enhanced muscle mass in MSTN^+/PVD20H pig was mainly due to an increase in the number of muscle fibers. The expression of MSTN in the longissimus dorsi muscle of MSTN^+/PVD20H and MSTN^KO/PVD20H pigs was significantly downregulated, whereas that of myogenic regulatory factors, including MyoD, Myogenin, and Myf-5, was significantly upregulated when compared to those in the longissimus dorsi muscle of wild-type pigs. Meanwhile, the mutations also activated the PI3K/Akt pathway. The results of this study indicated that precise editing of the MSTN signal peptide can enhance porcine muscle development without markedly affecting the expression of mature MSTN peptide, which could exert other beneficial biological functions in the edited pigs.