Yuji Uchida

Mdx respiratory impairment following fibrosis of the diaphragm

Duchenne muscular dystrophy (DMD) is a progressive muscle-wasting disease that causes respiratory or cardiac failure and results in death at about 20 years of age. An animal model of DMD, the mdx mouse, is commonly used to estimate dystrophic pathology. The pathological features of limb muscles are relatively mild, however the diaphragm is severely affected and exhibits a degenerative pattern similar to that observed in human DMD. Although, the muscle strength assay of the dystrophic diaphragm has been used to estimate mdx respiratory impairment, systemic functional assessments compared with histopathological analysis have not been demonstrated. Here, we report a sensitive procedure using whole-body plethysmography to monitor respiratory parameters detected during early respiratory insufficiency in the mdx mouse. The dystrophic changes in the diaphragm lead to respiratory dysfunctions. These methods may be useful to assess the therapeutic approaches for the mdx mouse.

Transduction of full-length dystrophin to multiple skeletal muscles improves motor performance and life span in utrophin/dystrophin double knockout mice.

Duchenne muscular dystrophy (DMD) is a fatal, progressive, muscle-wasting disease caused by defects in the dystrophin. No viral vector except the helper-dependent adenovirus vector (HDAdv) can package 14-kilobase (kb) full-length dystrophin complementary DNA (cDNA), and HDAdv is considerably safer than old-generation adenovirus vectors because of the large-size deletion in its genome. We have generated HDAdv that carries myc-tagged murine full-length dystrophin cDNA (HDAdv-myc-mFLdys). We injected it into multiple proximal muscles of 7-day-old utrophin/dystrophin double knockout mice (dko mice) (which typically show symptoms quite similar to human DMD) because the proximal muscles are affected in DMD patients. Eight weeks after the injections, the transduced dystrophin was widely expressed, and we found a significant reduction in centrally nucleated myofibers and the restoration of the dystrophin-associated proteins, beta-dystroglycan (beta-DG) and alpha-sarcoglycan (alpha-SG), as well as neuronal nitric oxide synthase (nNOS). The injected dko mice also showed an increase in body weight, an improvement in motor performance, and a prolongation of life span. Using HDAdv, we could treat DMD model mice even by transferring the therapeutic gene into multiple skeletal muscles. Our results suggest that multiple intramuscular administrations of HDAdv carrying full-length dystrophin cDNA may reduce symptoms and compensate for lost functions in DMD patients.

Lipopolysaccharide Decreases Single Immunoglobulin Interleukin-1 Receptor-related Molecule (SIGIRR) Expression by Suppressing Specificity Protein 1 (Sp1) via the Toll-like Receptor 4 (TLR4)-p38 Pathway in Monocytes and Neutrophils

Background: Single immunoglobulin interleukin-1 receptor-related molecule (SIGIRR) is a negative inflammatory regulator whose regulatory mechanism is mainly described in epithelial tissues. Results: Higher monocytic and neutrophilic SIGIRR expression is maintained by Sp1. Conclusion: Lipopolysaccharide decreases SIGIRR expression by suppressing Sp1 via the TLR4-p38 pathway. Significance: The LPS-dependent SIGIRR down-regulation may be critical for optimal inflammatory responses in immune cells. Single immunoglobulin interleukin-1 receptor-related molecule (SIGIRR) is one of the immunoglobulin-like membrane proteins that is crucial for negative regulation of toll-like receptor 4 (TLR4) and interleukin-1 receptor. Despite the importance of understanding its expression and function, knowledge is limited on the regulatory mechanism in the epithelial tissues, such as the liver, lung, and gut, where its predominant expression is originally described. Here, we found expression of SIGIRR in non-epithelial innate immune cells, including primary peripheral blood monocytes, polymorphonuclear neutrophils, monocytic RAW264 cells, and neutrophilic-differentiated HL-60 cells. Consistent with previous findings in epithelial tissues, SIGIRR gene and protein expression were also down-regulated by LPS treatment in a time-dependent manner in primary blood monocytes and polymorphonuclear neutrophils. A reduction was also observed in RAW264 and differentiated HL-60 cells. Notably, exogenous introduction of the dominant negative form of TLR4 and siRNA of p38 resulted in inhibition of LPS-induced SIGIRR down-regulation, whereas treatment with p38 activator anisomycin showed a dose-dependent decrease in SIGIRR expression, suggesting TLR4-p38 signal as a critical pathway for LPS-induced SIGIRR down-regulation. Finally, reporter gene and chromatin immunoprecipitation assays demonstrated that Sp1 is a key factor that directly binds to the proximal promoter of SIGIRR gene and consequently regulates basal SIGIRR expression, which is negatively regulated by the LPS-dependent TLR4-p38 pathway. In summary, the data precisely demonstrate how LPS down-regulates SIGIRR expression and provide a role of LPS signal that counteracts Sp1-dependent basal promoter activation of SIGIRR gene via TLR4-p38 pathway in non-epithelial innate immune cells.

A reversible lesion of the corpus callosum splenium with adult influenza-associated encephalitis/encephalopathy: a case report.

ABstractIntroductionInfluenza virus-associated encephalitis/encephalopathy is a severe childhood illness with a poor prognosis. Adult case reports are rare and, to date, there have been no reports of adults with a mild subcortical encephalopathy with reversible lesions of the corpus callosum splenium.Case presentationA previously healthy 35-year-old man presented with acute progressive tetraplegia, transcortical motor aphasia and a mild decrease in his consciousness during his recovery after receiving oseltamivir phosphate treatment, and influenza type A antiviral medication. The initial magnetic resonance imaging study at day 1 showed symmetrical diffuse lesions in the white matter and a lesion on the central portion of the corpus callosum splenium. These findings had resolved on follow-up studies at day 8 and day 146. His neurological deficits mostly recovered within 12 hours following methylprednisolone pulse therapy. The levels of interleukin-6 and interleukin-10 in his blood and cerebrospinal fluid were initially elevated, but rapidly decreased to normal levels by day 8.ConclusionIt is important for clinicians to recognize that even in adulthood, the subcortical encephalopathy observed during the therapeutic treatment for influenza type A infection can occur in conjunction with a reversible lesion of the corpus callosum, which may recover quickly. In addition, the cytokine storm in the blood system and the corticospinal cavity may play an important role in the etiology of the disease process.

Effective repetitive dystrophin gene transfer into skeletal muscle of adult mdx mice using a helper-dependent adenovirus vector expressing the coxsackievirus and adenovirus receptor (CAR) and dystrophin

The helper‐dependent adenovirus (HDAd) vector is less immunogenic and has a larger cloning capacity of up to 37 kb enough to carry the full‐length dystrophin cDNA. However, high and long‐term expression of dystrophin transduced to mature muscle still remains difficult. One of the main reasons for this is that the expression of the coxsackievirus and adenovirus receptor (CAR) is very low in mature muscle.

Rescue From Respiratory Dysfunction by Transduction of Full-length Dystrophin to Diaphragm via the Peritoneal Cavity in Utrophin/Dystrophin Double Knockout Mice

Duchenne muscular dystrophy (DMD) is an inherited severe muscle wasting disorder with, thus far, no effective therapy. DMD causes respiratory and cardiac failure as well as muscle wastage. Among the various symptoms, respiratory insufficiency is a major cause of death in DMD patients at about 20 years of age. So, naturally, the improvement of respiratory function will extend the patients life. We report here, for the first time, a sensitive procedure using whole-body plethysmography to monitor respiratory parameters detected in the utrophin/dystrophin double knockout mouse (dko mouse), showing quite similar systemic symptoms to human DMD including restrictive ventilatory impairment. Furthermore, we show that a highly efficient dystrophin-transduction to the dkos diaphragm--achieved by simple intraperitoneal injection of a helper-dependent adenovirus vector (HDAdv) containing the full-length dystrophin expression cassette--provided beneficial results. In spite of dystrophin expression only in the diaphragm, this focal gene transfer could result in the rescue from ventilatory impairment (increased tidal volume (TV) and improvement of compensatory hyperpnea). Our result suggests that a DMD patients mortal ventilatory impairment may be improved via technically easy means through the intraperitoneal injection of HDAdv.

Muscle Fiber Type-Predominant Promoter Activity in Lentiviral-Mediated Transgenic Mouse

Variations in gene promoter/enhancer activity in different muscle fiber types after gene transduction was noticed previously, but poorly analyzed. The murine stem cell virus (MSCV) promoter drives strong, stable gene expression in hematopoietic stem cells and several other cells, including cerebellar Purkinje cells, but it has not been studied in muscle. We injected a lentiviral vector carrying an MSCV-EGFP cassette (LvMSCV-EGFP) into tibialis anterior muscles and observed strong EGFP expression in muscle fibers, primary cultured myoblasts, and myotubes isolated from injected muscles. We also generated lentiviral-mediated transgenic mice carrying the MSCV-EGFP cassette and detected transgene expression in striated muscles. LvMSCV-EGFP transgenic mice showed fiber type-dependent variations in expression: highest in types I and IIA, intermediate in type IID/X, and lowest in type IIB fibers. The soleus and diaphragm muscles, consisting mainly of types I and IIA, are most severely affected in the mdx mouse model of muscular dystrophy. Further analysis of this promoter may have the potential to achieve certain gene expression in severely affected muscles of mdx mice. The Lv-mediated transgenic mouse may prove a useful tool for assessing the enhancer/promoter activities of a variety of different regulatory cassettes.

Cre/loxP-mediated adenovirus type 5 packaging signal excision demonstrates that core element VI is sufficient for virus packaging

Previous analyses have demonstrated that packaging of the adenovirus type 5 (Ad5) genome is dependent on at least seven cis-acting elements, called AI to AVII, which are located in the left-end region of the genome. These elements have different packaging efficiencies, and without AI through AV, viral DNA cannot be packaged. Here we report the identification of the cis-acting Ad5 packaging domain in vivo by using the Cre/loxP system. We found that an adenoviral DNA fragment (nt 192 to nt 358), which includes elements AI to AV, is excised by Cre recombinase and packaged into capsids. Furthermore, this mutant adenovirus replicated so efficiently by repetitive propagation that its purification by CsCI equilibrium gradient was possible. This study clarified that the region from nt 358 to nt 454 on the viral genome is sufficient for packaging. Recently, the helper-dependent adenoviral vector (HDAd) construction system has been developed for the purpose of gene therapy. This system uses a helper virus with two parallel loxP sites flanking the packaging signal. This region is eliminated by Cre-mediated excision, which prevents helper virus packaging. Our data provide useful information regarding factors affecting efficient elimination.

Heatstroke in patients with Parkinson’s disease

We present two Parkinson’s disease (PD) patients, who experienced heatstroke. Both patients manifested central nervous system dysfunction with elevated core temperature. Despite adequate lowering of the body temperature, multiorgan-dysfunction syndrome including encephalopathy, rhabdomyolysis, acute renal failure, acute respiratory failure, and disseminated intravascular coagulopathy was noted in one patient, leading to permanent neurologic damage. Because the ensuing multiorgan dysfunction could determine the functional prognosis in heatstroke patients, it is important to provide information about the prevention of heatstroke to patients, who are isolated or are severely disabled in the advanced stages of PD.

Regions downstream from the WW domain of dystrophin are important for binding to postsynaptic densities in the brain.

In order to investigate the mechanism of dystrophin localization in the central nervous system (CNS), we generated adenovirus vectors that contained minidystrophin or truncated minidystrophin cDNA. We infected a primary neuronal culture derived from mdx mouse hippocampus with these viruses. Minidystrophin was observed along the plasma membrane as punctate dots or very short segments. In double immunofluorescence staining with anti-dystrophin and anti-postsynaptic density-95 antibodies, we observed that these proteins entirely colocalized. On the other hand, the truncated minidystrophin, which has deleted WW, cysteine-rich and C-terminal domains, was homogenously expressed in cytoplasm, neurites and axons. These findings suggest that a binding site to postsynaptic densities exists in the region extending from the WW domain to the C-terminal domain of dystrophin and that this site is necessary for binding to membrane.