Mislocalization of TDP-43 in the G93A mutant SOD1 transgenic mouse model of ALS

Previous evidence demonstrates that TAR DNA binding protein (TDP-43) mislocalization is a key pathological feature of amyotrophic lateral sclerosis (ALS). TDP-43 normally shows nuclear localization, but in CNS tissue from patients who died with ALS this protein mislocalizes to the cytoplasm. Disease specific TDP-43 species have also been reported to include hyperphosphorylated TDP-43, as well as a C-terminal fragment. Whether these abnormal TDP-43 features are present in patients with SOD1-related familial ALS (fALS), or in mutant SOD1 over-expressing transgenic mouse models of ALS remains controversial. Here we investigate TDP-43 pathology in transgenic mice expressing the G93A mutant form of SOD1. In contrast to previous reports we observe redistribution of TDP-43 to the cytoplasm of motor neurons in mutant SOD1 transgenic mice, but this is seen only in mice having advanced disease. Furthermore, we also observe rounded TDP-43 immunoreactive inclusions associated with intense ubiquitin immunoreactivity in lumbar spinal cord at end stage disease in mSOD mice. These data indicate that TDP-43 mislocalization and ubiquitination are present in end stage mSOD mice. However, we do not observe C-terminal TDP-43 fragments nor TDP-43 hyperphosphorylated species in these end stage mSOD mice. Our findings indicate that G93A mutant SOD1 transgenic mice recapitulate some key pathological, but not all biochemical hallmarks, of TDP-43 pathology previously observed in human ALS. These studies suggest motor neuron degeneration in the mutant SOD1 transgenic mice is associated with TDP-43 histopathology.     

Pre-symptomatic detection of chronic motor deficits and genotype prediction in congenic B6.SOD1 ALS mouse model

Amyotrophic lateral sclerosis (ALS) is an incurable progressive paralytic motor neuron disease with limited therapeutic options. Since their creation by Gurney et al. (1994) [Science 264:1772–1775], transgenic superoxide dismutase-1 with glycine to alanine switch at codon 93 (SOD1^G93A) mice have become the benchmark pre-clinical model for screening ALS therapies. Surprisingly, despite physiological, anatomical, ultrastructural and biochemical evidence of early motor system dysfunction, it has proven difficult to detect motor performance deficits in pre-symptomatic SOD1^G93A mice. As an alternative to conventional forced motor tests, we investigated the progression of motor performance deficits in freely behaving pre-symptomatic congenic B6.SOD1^G93A mice. We found that motor performance deficits began several weeks prior to the onset of overt clinical symptoms (postnatal day 45). More importantly, once motor performance deficits manifested, they persisted in parallel with disease progression. In addition, two physical measures of muscle girth revealed progressive hindlimb muscle atrophy that predicted genotype in individual pre-symptomatic mice with 80% accuracy. Together, these data suggest that muscle girth is a reliable and indirect measure of hindlimb muscle denervation and an early, objective marker for disease onset in congenic B6.SOD1^G93A ALS mice. Moreover, we present regression equations based on hindlimb muscle girth for predicting genotype in future studies using B6.SOD1^G93A mice. These findings support new objective criteria for clinical disease onset and provide objective measures that require little expertise. These studies demonstrate a cost-effective approach for more thorough evaluation of neuroprotective strategies that seek to disrupt disease mechanisms early in the disease process. To our knowledge, these findings are the first to report early chronic motor performance and physical deficits that are coincident with the earliest known motor dysfunction in any ALS mouse model.     

Helicobacter pylori heat shock protein 60 antibodies are associated with gastric cancer

Helicobacter pylori infection causes atrophic gastritis, peptic ulcer, and gastric cancer. The host immune response plays an important role in the pathogenesis of H. pylori-related diseases. Heat shock proteins are antigens involved in various diseases. This study evaluated seropositivity for antibodies to H. pylori heat shock protein 60 in patients with gastric cancer.     

A soluble activin type IIB receptor improves function in a mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurologic disease characterized by progressive weakness that results in death within a few years of onset by respiratory failure. Myostatin is a member of the TGF-β superfamily that is predominantly expressed in muscle and acts as a negative regulator of muscle growth. Attenuating myostatin has previously been shown to produce increased muscle mass and strength in normal and disease animal models. In this study, a mouse model of ALS (SOD1^G93A transgenic mice) was treated with a soluble activin receptor, type IIB (ActRIIB.mFc) which is a putative endogenous signaling receptor for myostatin in addition to other ligands of the TGF-β superfamily. ActRIIB.mFc treatment produces a delay in the onset of weakness, an increase in body weight and grip strength, and an enlargement of muscle size whether initiated pre-symptomatically or after symptom onset. Treatment with ActRIIB.mFc did not increase survival or neuromuscular junction innervation in SOD1^G93A transgenic mice. Pharmacologic treatment with ActRIIB.mFc was superior in all measurements to genetic deletion of myostatin in SOD1^G93A transgenic mice. The improved function of SOD1^G93A transgenic mice following treatment with ActRIIB.mFc is encouraging for the development of TGF-β pathway inhibitors to increase muscle strength in patients with ALS.     

SOD1 (A4V)‐mediated ALS presenting with lower motor neuron facial diplegia and unilateral vocal cord paralysis

Amyotrophic lateral sclerosis (ALS) is a progressive degenerative neuromuscular disease that presents with upper and lower motor neuron signs. Although the majority of ALS cases are sporadic, 10% are familial, of which 20%–25% result from mutations in the superoxide dismutase (SOD1) gene. We describe a novel case of SOD1 (A4V)‐mediated ALS that presented with lower motor neuron facial diplegia and unilateral vocal cord paralysis. This case expands the phenotypic expression of the A4V mutation. Muscle Nerve, 2009     

肌肉注射脂联素基因对高脂饮食大鼠氧化应激作用的影响

构建人脂联素(hAPN)基因的质粒表达载体,研究其体外转移后的表达情况.通过基因重组构建脂联素基因表达系统,电转导法导入大鼠股部肌肉,RT-PCR检测大鼠肌肉注射部位组织中mRNA水平的表达情况,同时监测外周血中SOD、MDA水平.结果表明:RT-PCR显示该基因能在肌肉组织中表达,血清中SOD水平相应升高,注射后两周达到最高水平;MDA水平降低,注射两周后达到最低水平,持续大约两周.脂联素表达系统可以在动物体内表达,增加了自由基的清除,抑制了脂质过氧化物的产生.     

2型糖尿病肾病患者红细胞免疫功能与脂质过氧化的关系

目的：探讨了2型糖尿病肾病患者红细胞免疫功能的变化及其与脂质过氧化的关系。方法：应用红细胞酵母花环法对34例2型糖尿病肾病患者进行了红细胞免疫功能和化学比色法测定血清丙二醛（MDA）、超过氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-PX）含量,并与35名正常健康人作比较。结果：2型糖尿病患者红细胞免疫复合物（RBC-IC）花环率和MDA水平明显升高（P〈0.05～0.01）,而红细胞C3b受体（RBCc3b-RR）、SOD、GSH-PX水平显著低于正常（P〈0.01）。相关分析显示：RBCc3b花环与MDA呈显著负相关（r=-0.4012,P〈0.05）,RBC-ICR与MDA呈显著正相关（r=0.5928,P〈0.01）。结论：2型糖尿病患者红细胞免疫功能降低与活性氧代谢紊乱密切相关。     

Live imaging of amyotrophic lateral sclerosis pathogenesis: Disease onset is characterized by marked induction of GFAP in Schwann cells

Amyotrophic lateral sclerosis (ALS) is a late‐onset neurological disease characterized by progressive loss of motor neurons. At present, the pathological events precipitating disease onset and the exact pattern of disease progression are not fully understood. Recent studies suggest that glial cells, in particular activated astrocytes, can release factors that can directly kill motor neurons. To further investigate the involvement of glial cells (astrocytes and Schwann cells) in the pathogenesis of ALS, we generated ALS‐(GFAP‐luciferase/SOD^G93A) reporter mouse in which upregulation of glial fibrillary acidic protein (GFAP) can be visualized from live animals throughout the different stages of disease. Our results suggest that the disease in mice is initiated simultaneously in the spinal cord and in the peripheral nerves and is characterized by several cycles of GFAP upregulation. Immunohistochemical analysis confirmed that the induction GFAP bioluminescence signals were associated with the significant increases in GFAP immunoreactivity. The first pathological GFAP signals occurring at 25–30 days were asymptomatic and detectable at the level of lumbar spinal cord projections and at the periphery. These early events were then followed by GFAP promoter inductions that were associated with the distinct clinical symptoms. As expected, the onset of paralysis (112 days) was associated with the gradual and marked GFAP upregulation in the spinal cord. Interestingly, however, the disease onset (90 days) was characterized by sharp and synchronized induction of GFAP in peripheral nerve Schwann cells suggesting that peripheral nerves pathology/denervation and associated Schwann cell stress may play an important role in the ALS pathogenesis. © 2008 Wiley‐Liss, Inc.     

Repression of tau hyperphosphorylation by chronic endurance exercise in aged transgenic mouse model of tauopathies

The present study was undertaken to investigate whether chronic endurance exercise affects tau phosphorylation levels in the brain with Alzheimer's disease (AD)‐like pathology. To address this, the transgenic (Tg) mouse model of tauopathies, Tg‐NSE/htau23, which expresses human tau23 in the brain, was chosen. Animals were subjected to chronic exercise for 3 months from 16 months of age. The exercised Tg mouse groups were treadmill run at speeds of 12 m/min (intermediate exercise group) or 19 m/min (high exercise group) for 1 hr/day, 5 days/week, during the 3‐month period. Chronic endurance exercise in Tg mice increased the expression of Cu/Zn‐superoxide dismutase (SOD) and catalase, and also their enzymatic activities in the brain. In parallel, chronic exercise in Tg mice up‐regulated the expression of phospho‐PKCα, phospho‐AKT, and phospho‐PI3K, and down‐regulated the expressions of phospho‐PKA, phosphor‐p38, phospho‐JNK, and phospho‐ERK. Moreover, chronic exercise up‐regulated both cytosolic and nuclear levels of β‐catenin, and the expression of T‐cell factor‐4 (Tcf‐4) and cyclin D1 in the brain. As a consequence of such changes, the levels of phospho‐tau in the brain of Tg mice were markedly decreased after exercise. Immunohistochemical analysis showed an exercised‐induced decrease of the phospho‐tau levels in the CA3 subregion of the hippocampus. These results suggest that chronic endurance exercise may provide a therapeutic potential to alleviate the tau pathology. © 2009 Wiley‐Liss, Inc.