This study investigated the mechanism by which Jianpi Bushen Yiqi Decoction promotes acetylcholine receptor(AChR) clustering in myasthenia gravis through the Agrin/low-density lipoprotein receptor-related protein 4(LRP4)/muscle-specific receptor tyrosine kinases(MuSK) signaling pathway. A total of 114 female C57BL/6J mice were divided into the normal group, modeling group, and solvent control group. The normal group and the solvent control group were immunized with phosphate-buffered saline(PBS), while the modeling group was established as an experimental autoimmune myasthenia gravis(EAMG) model using the murine-derived AChR-α subunit R97-116 peptide fragment. After successful modeling, the mice were randomly assigned to the model group, the low-, medium-, and high-dose Jianpi Bushen Yiqi Decoction groups, and the prednisone group. After four weeks of continuous treatment, muscle strength was assessed using Lennon scores and grip strength tests. Immunofluorescence staining was conducted on differentiated C2C12 myotubes incubated with a drug-containing serum to observe the number of AChR clusters. The integrity of AChR on myofilaments in mouse gastrocnemius muscles was further assessed by immunofluorescence staining. Hematoxylin-Eosin(HE)staining was applied to examine pathological changes in the gastrocnemius muscles of EAMG mice treated with Jianpi Bushen Yiqi Decoction. Western blot was utilized to detect the expression of key proteins in the Agrin/LRP4/MuSK signaling pathway in both C2C12 myotubes and mouse gastrocnemius muscles. The results demonstrated that compared to the model group, the prednisone group exhibited a significant decrease in the body weights of mice, whereas no significant differences in the body weights of mice were observed among the low-, medium-, and high-dose Jianpi Bushen Yiqi Decoction groups. All treatment groups showed significantly improved grip strength and Lennon scores. Additionally, the formula promoted AChR clustering on myotubes and enhanced AChR integrity in gastrocnemius myofilaments and reduced inflammatory infiltration between muscle tissue and fibrous hyperplasia. Furthermore, Jianpi Bushen Yiqi Decoction upregulated the protein expression of AChRα1, Agrin, and p-MuSK in C2C12 myotubes and increased the protein expression of AChRα1, Agrin, MuSK, p-MuSK, LRP4, and docking protein 7(Dok-7)in gastrocnemius tissue. In conclusion, Jianpi Bushen Yiqi Decoction may promote AChR clustering by targeting key proteins in the Agrin/LRP4/MuSK signaling pathway, thereby improving neuromuscular junction function and enhancing muscle strength.
Animals ; Agrin/genetics* ; Mice ; Drugs, Chinese Herbal/administration & dosage* ; Signal Transduction/drug effects* ; Receptors, Cholinergic/genetics* ; Female ; Mice, Inbred C57BL ; Receptor Protein-Tyrosine Kinases/genetics* ; Neuromuscular Junction/metabolism* ; Myasthenia Gravis, Autoimmune, Experimental/physiopathology* ; Humans ; LDL-Receptor Related Proteins

Glycosaminoglycans are important structural components in the skin and exist as various proteoglycan forms, except hyaluronic acid. Heparan sulfate (HS), one of the glycosaminoglycans, is composed of repeated disaccharide units, which are glucuronic acids linked to an N-acetyl-glucosamine or its sulfated forms. To investigate acute ultraviolet (UV)-induced changes of HS and HS proteoglycans (HSPGs), changes in levels of HS and several HSPGs in male human buttock skin were examined by immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR) after 2 minimal erythema doses (MED) of UV irradiation (each n = 4-7). HS staining revealed that 2 MED of UV irradiation increased its expression, and staining for perlecan, syndecan-1, syndecan-4, CD44v3, and CD44 showed that UV irradiation increased their protein levels. However, analysis by real-time qPCR showed that UV irradiation did not change mRNA levels of CD44 and agrin, and decreased perlecan and syndecan-4 mRNA levels, while increased syndecan-1 mRNA level. As HS-synthesizing or -degrading enzymes, exostosin-1 and heparanase mRNA levels were increased, but exostosin-2 was decreased by UV irradiation. UV-induced matrix metalloproteinase-1 expression was confirmed for proper experimental conditions. Acute UV irradiation increases HS and HSPG levels in human skin, but their increase may not be mediated through their transcriptional regulation.
Adult ; Agrin/genetics ; Antigens, CD44/genetics ; Base Sequence ; DNA Primers/genetics ; Gene Expression/radiation effects ; Glucuronidase/genetics ; Heparan Sulfate Proteoglycans/genetics/*metabolism ; Heparitin Sulfate/metabolism ; Humans ; Male ; Matrix Metalloproteinase 1/genetics ; N-Acetylglucosaminyltransferases/genetics ; RNA, Messenger/genetics/metabolism ; Skin/*metabolism/*radiation effects ; Skin Aging/genetics/physiology ; Syndecan-1/genetics ; Syndecan-4/genetics ; Ultraviolet Rays/*adverse effects ; Young Adult

OBJECTIVETo investigate the effects of transfection of agrin gene on the recovery of muscle function after a free neurovascular muscle transfer.

METHODSThe electrical gene transfection was performed when the gracilis muscle of the SD rat was completed free neurovascular transfer. The experimental group was treated with pCS2+ -agrin, the group with plasmid pCS2+ as the negative control and the group with normal saline as the frank control. The muscle function, expression of neural agrin and the junctional nAChR number was measured after the operation.

RESULTSAt 4, 5 and 10 weeks postoperatively, the pCS2+ -agrin group was significantly better than the control groups in muscle function (P < 0.05 ). The immunohistochemical staining showed an increasing deposition of the agrin protein near the endplate at 1 and 5 weeks after the operation, but decreasing remarkably to the level of control groups at 10 weeks postoperatively. The pCS2+ -agrin group was significantly more than the control groups in junctional nAChR number at every points of the time postoperatively.

CONCLUSIONSTransfection of agrin gene in the transferred muscle may increase the early recovery of muscle function.

Agrin ; genetics ; Animals ; Female ; Genetic Therapy ; Genetic Vectors ; Muscle Proteins ; genetics ; Muscle, Skeletal ; transplantation ; Rats ; Rats, Sprague-Dawley ; Recovery of Function ; Transfection