Wafer-Scale Room-Temperature Bonding of Smooth Au/Ti-Based Getter Layer for Vacuum Packaging.

This study demonstrates room-temperature bonding using a getter layer for the vacuum packaging of microsystems. A thick Ti layer covered with an Au layer is utilized as a getter layer because it can absorb gas molecules in the package. Additionally, smooth Au surfaces can form direct bonds for hermetic sealing at room temperature. Direct bonding using a getter layer can simplify the vacuum packaging process; however, typical getter layers are rough in bonding formation. This study demonstrates two fabrication techniques for smooth getter layers. In the first approach, the Au/Ti layer is bonded to an Au layer on a smooth SiO2 template, and the Au/SiO2 interface is mechanically exfoliated. Although the root-mean-square roughness was reduced from 2.00 to 0.98 nm, the surface was still extremely rough for direct bonding. In the second approach, an Au/Ti/Au multilayer on a smooth SiO2 template is bonded with a packaging substrate, and the Au/SiO2 interface is exfoliated. The transferred Au/Ti/Au getter layer has a smooth surface with the root-mean-square roughness of 0.54 nm and could form wafer-scale direct bonding at room temperature. We believe that the second approach would allow a simple packaging process using direct bonding of the getter layer.

Cardiomyopathy and altered integrin-actin signaling in Fhl1 mutant female mice.

X-linked scapuloperoneal myopathy (X-SM), one of Four-and-a-half LIM 1 (FHL1) related diseases, is an adult-onset slowly progressive myopathy, often associated with cardiomyopathy. We previously generated a knock-in mouse model that has the same mutation (c.365 G > C, p.W122S) as human X-SM patients. The mutant male mouse developed late-onset slowly progressive myopathy without cardiomyopathy. In this study, we observed that heterozygous (Het) and homozygous (Homo) female mice did not show alterations of skeletal muscle function or histology. In contrast, 20-month-old mutant female mice showed signs of cardiomyopathy on echocardiograms with increased systolic diameter [wild-type (WT): 2.74 ± 0.22 mm, mean ± standard deviation (SD); Het: 3.13 ± 0.11 mm, P < 0.01; Homo: 3.08 ± 0.37 mm, P < 0.05) and lower fractional shortening (WT: 31.1 ± 4.4%, mean ± SD; Het: 22.7 ± 2.5%, P < 0.01; Homo: 22.4 ± 6.9%, P < 0.01]. Histological analysis of cardiac muscle revealed frequent extraordinarily large rectangular nuclei in mutant female mice that were also observed in human cardiac muscle from X-SM patients. Western blot demonstrated decreased Fhl1 protein levels in cardiac muscle, but not in skeletal muscle, of Homo mutant female mice. Proteomic analysis of cardiac muscle from 20-month-old Homo mutant female mice indicated abnormalities of the integrin signaling pathway (ISP) in association with cardiac dysfunction. The ISP dysregulation was further supported by altered levels of a subunit of the ISP downstream effectors Arpc1a in Fhl1 mutant mice and ARPC1A in X-SM patient muscles. This study reveals the first mouse model of FHL1-related cardiomyopathy and implicates ISP dysregulation in the pathogenesis of FHL1 myopathy.

Fhl1 W122S causes loss of protein function and late-onset mild myopathy.

A member of the four-and-a-half-LIM (FHL) domain protein family, FHL1, is highly expressed in human adult skeletal and cardiac muscle. Mutations in FHL1 have been associated with diverse X-linked muscle diseases: scapuloperoneal (SP) myopathy, reducing body myopathy, X-linked myopathy with postural muscle atrophy, rigid spine syndrome (RSS) and Emery-Dreifuss muscular dystrophy. In 2008, we identified a missense mutation in the second LIM domain of FHL1 (c.365 G>C, p.W122S) in a family with SP myopathy. We generated a knock-in mouse model harboring the c.365 G>C Fhl1 mutation and investigated the effects of this mutation at three time points (3-5 months, 7-10 months and 18-20 months) in hemizygous male and heterozygous female mice. Survival was comparable in mutant and wild-type animals. We observed decreased forelimb strength and exercise capacity in adult hemizygous male mice starting from 7 to 10 months of age. Western blot analysis showed absence of Fhl1 in muscle at later stages. Thus, adult hemizygous male, but not heterozygous female, mice showed a slowly progressive phenotype similar to human patients with late-onset muscle weakness. In contrast to SP myopathy patients with the FHL1 W122S mutation, mutant mice did not manifest cytoplasmic inclusions (reducing bodies) in muscle. Because muscle weakness was evident prior to loss of Fhl1 protein and without reducing bodies, our findings indicate that loss of function is responsible for the myopathy in the Fhl1 W122S knock-in mice.

Mutant superoxide dismutase 1 (SOD1), a cause of amyotrophic lateral sclerosis, disrupts the recruitment of SMN, the spinal muscular atrophy protein to nuclear Cajal bodies.

Spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are among the most common motor neuron diseases to afflict the human population. A deficiency of the survival of motor neuron (SMN) protein causes SMA and is also reported to be an exacerbating factor in the development of ALS. However, pathways linking the two diseases have yet to be defined and it is not clear precisely how the pathology of ALS is aggravated by reduced SMN or whether mutant proteins underlying familial forms of ALS interfere with SMN-related biochemical pathways to exacerbate the neurodegenerative process. In this study, we show that mutant superoxide dismutase-1 (SOD1), a cause of familial ALS, profoundly alters the sub-cellular localization of the SMN protein, preventing the formation of nuclear 'gems' by disrupting the recruitment of the protein to Cajal bodies. Overexpressing the SMN protein in mutant SOD1 mice, a model of familial ALS, alleviates this phenomenon, most likely in a cell-autonomous manner, and significantly mitigates the loss of motor neurons in the spinal cord and in culture dishes. In the mice, the onset of the neuromuscular phenotype is delayed and motor function enhanced, suggestive of a therapeutic benefit for ALS patients treated with agents that augment the SMN protein. Nevertheless, this finding is tempered by an inability to prolong survival, a limitation most likely imposed by the inexorable denervation that characterizes ALS and eventually disrupts the neuromuscular synapses even in the presence of increased SMN.

Tardive Dyskinesia With Chorea-Ballism Improved by Valbenazine: A Case Report.

Tardive dyskinesia (TD) is an involuntary muscle movement typically caused by prolonged exposure to antipsychotic medications. Depending on the symptom severity and the affected body parts, it can cause a terrible decline in patients' daily activities and life quality. TD often persists despite discontinuation of the offending drugs. There was no approved or effective agent to treat the patients until valbenazine, a vesicular monoamine transporter-2 inhibitor, became available. We report the case of a 64-year-old woman who started to take antipsychotics at the age of her late 20s for her schizophrenic symptoms and later developed left arm chorea-ballism in mid-50s. The patient's involuntary movements got progressively worse even after being freed from the medications and caused severe body weight loss due to difficulties in taking meals. Daily treatment with valbenazine gradually mitigated her symptoms, resulting in significant improvement in her feeding activities, body weight, and daily life quality. This is the first report, to our knowledge, describing the therapeutic potential of valbenazine to improve chorea-ballism associated with TD. Our observation highlights that valbenazine may relieve a broader spectrum of antipsychotic-induced involuntary movements.

Physical Exercise Counteracts Aging-Associated White Matter Demyelination Causing Cognitive Decline.

In the central nervous system, oligodendrocytes wrap around neuronal axons to form myelin, an insulating layer or sheath that allows for the efficient conductance of action potentials. In addition to structural insulation, myelin provides encased axons with nutrient, metabolic and defensive support. Demyelination, or myelin loss, can therefore cause axonal dysfunction, leading to neurological impairment and disease. In Alzheimer's disease (AD), progressive white matter demyelination is acknowledged as one of the earliest pathologies preceding symptom onset. Unfortunately, current pharmacotherapy for slowing demyelination or promoting remyelination in AD is nonexistent. Exercise is recognized for its wide-ranging benefits to human health, including improved mental health and the prevention of lifestyle-related diseases. Mounting evidence suggests the contribution of physical activity in delaying the progression of dementia in elderly populations. Recent mechanistic studies have shown that exercise facilitates myelination in the brain through the vitalization of intrinsic pro-myelination cues, such as increased neurotrophic factors and electrical activity. In this review, we summarize and discuss the potential of physical exercise on counteracting aging-associated white matter demyelination, which causes cognitive decline in AD. We highlight the need of further basic and clinical research investigations on this topic to establish novel approaches for healthy and improved brain aging.

Longitudinal transcriptomic analysis of mouse sciatic nerve reveals pathways associated with age-related muscle pathology.

BACKGROUND: Sarcopenia, the age-associated decline in skeletal muscle mass and strength, has long been considered a disease of muscle only, but accumulating evidence suggests that sarcopenia could originate from the neural components controlling muscles. To identify early molecular changes in nerves that may drive sarcopenia initiation, we performed a longitudinal transcriptomic analysis of the sciatic nerve, which governs lower limb muscles, in aging mice. METHODS: Sciatic nerve and gastrocnemius muscle were obtained from female C57BL/6JN mice aged 5, 18, 21 and 24 months old (n = 6 per age group). Sciatic nerve RNA was extracted and underwent RNA sequencing (RNA-seq). Differentially expressed genes (DEGs) were validated using quantitative reverse transcription PCR (qRT-PCR). Functional enrichment analysis of clusters of genes associated with patterns of gene expression across age groups (adjusted P-value < 0.05, likelihood ratio test [LRT]) was performed. Pathological skeletal muscle aging was confirmed between 21 and 24 months by a combination of molecular and pathological biomarkers. Myofiber denervation was confirmed with qRT-PCR of Chrnd, Chrng, Myog, Runx1 and Gadd45ɑ in gastrocnemius muscle. Changes in muscle mass, cross-sectional myofiber size and percentage of fibres with centralized nuclei were analysed in a separate cohort of mice from the same colony (n = 4-6 per age group). RESULTS: We detected 51 significant DEGs in sciatic nerve of 18-month-old mice compared with 5-month-old mice (absolute value of fold change > 2; false discovery rate [FDR] < 0.05). Up-regulated DEGs included Dbp (log2 fold change [LFC] = 2.63, FDR < 0.001) and Lmod2 (LFC = 7.52, FDR = 0.001). Down-regulated DEGs included Cdh6 (LFC = -21.38, FDR < 0.001) and Gbp1 (LFC = -21.78, FDR < 0.001). We validated RNA-seq findings with qRT-PCR of various up- and down-regulated genes including Dbp and Cdh6. Up-regulated genes (FDR < 0.1) were associated with the AMP-activated protein kinase signalling pathway (FDR = 0.02) and circadian rhythm (FDR = 0.02), whereas down-regulated DEGs were associated with biosynthesis and metabolic pathways (FDR < 0.05). We identified seven significant clusters of genes (FDR < 0.05, LRT) with similar expression patterns across groups. Functional enrichment analysis of these clusters revealed biological processes that may be implicated in age-related changes in skeletal muscles and/or sarcopenia initiation including extracellular matrix organization and an immune response (FDR < 0.05). CONCLUSIONS: Gene expression changes in mouse peripheral nerve were detected prior to disturbances in myofiber innervation and sarcopenia onset. These early molecular changes we report shed a new light on biological processes that may be implicated in sarcopenia initiation and pathogenesis. Future studies are warranted to confirm the disease modifying and/or biomarker potential of the key changes we report here.

A 44-Year-Old Alcohol-Dependent Man Who Recovered from Central Pontine Myelinolysis with Supportive Physical Therapy.

BACKGROUND Central pontine myelinolysis (CPM) includes symmetric demyelination of the central pons. CPM is a rare neurological disorder that generally develops after rapid correction of hyponatremia in individuals having underlying conditions, such as malnutrition, alcoholism, and severe burns. It can cause severe long-term disabilities. However, there is currently no pharmacotherapy capable of promoting remyelination, a process crucial for recovery from CPM. We present the case of a patient with alcoholism and malnutrition-related CPM, which developed following rapid correction of hyponatremia but then improved remarkably with supportive physical therapy. CASE REPORT A 44-year-old alcoholic and malnourished man was admitted to an emergency hospital for disorientation due to overdrinking, but later developed bulbar palsy after hyponatremia was unexpectedly, but rapidly, corrected. Axial scans of the diffusion-weighted brain MRI revealed a characteristic lesion known as a piglet sign in the central pons. Based on his underlying conditions, present episode of sodium correction, and MRI finding, the patient was diagnosed as having CPM, which progressively worsened, resulting in locked-in syndrome after 12 days. The patient was then transferred to a long-term care unit and received simple motion exercise daily, but no specific medication. His symptoms gradually improved, achieving discontinuation of tube feeding on day 21, independent walking on day 110, and discharge after 6 months. CONCLUSIONS This report highlights the importance of physical therapy, the potential of which is often underestimated despite its broad benefits for human health, as a readily applicable intervention for patients with CPM. Further understanding of mechanisms underlying exercise-induced myelination should contribute to establishing novel therapies for a wide spectrum of brain disorders.

Bonding formation and gas absorption using Au/Pt/Ti layers for vacuum packaging.

In this study, we developed a metal multilayer that can provide hermetic sealing after degassing the assemblies and absorbing the residual gases in the package. A package without a leak path was obtained by the direct bonding of the Au/Pt/Ti layers. After packaging, annealing at 450 °C caused thermal diffusion of the Ti underlayer atoms to the inner surface, which led to absorption of the residual gas molecules. These results indicated that a wafer coated with a Au/Pt/Ti layer can provide hermetic sealing and absorb residual gases, which can simplify vacuum packaging processes in the electronics industry.

Reduced SMN protein impairs maturation of the neuromuscular junctions in mouse models of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a common pediatric neuromuscular disorder caused by insufficient levels of the survival of motor neuron (SMN) protein. Studies involving SMA patients and animal models expressing the human SMN2 gene have yielded relatively little information about the earliest cellular consequences of reduced SMN protein. In this study, we have used severe- and mild-SMN2 expressing mouse models of SMA as well as material from human patients to understand the initial stages of neurodegeneration in the human disease. We show that the earliest structural defects appear distally and involve the neuromuscular synapse. Insufficient SMN protein arrests the post-natal development of the neuromuscular junction (NMJ), impairing the maturation of acetylcholine receptor (AChR) clusters into 'pretzels'. Pre-synaptic defects include poor terminal arborization and intermediate filament aggregates which may serve as a useful biomarker of the disease. These defects are reflected in functional deficits at the NMJ characterized by intermittent neurotransmission failures. We suggest that SMA might best be described as a NMJ synaptopathy and that one promising means of treating it could involve maintaining function at the NMJ.

Spinal muscular atrophy: new and emerging insights from model mice.

Spinal muscular atrophy (SMA) is a common and often fatal neurodegenerative disease that primarily afflicts infants and young children. SMA is caused by abnormally low levels of the survival motor neuron (SMN) protein resulting from a combination of recessively inherited mutations in the SMN1 gene and the presence of an almost identical but partially functional copy gene, SMN2. Absence of the uniquely human SMN2 gene in SMA patients has never been reported because the SMN protein is indispensable for cell survival. Modeling SMA in animals therefore poses a challenge. This review describes the different strategies used to overcome this hurdle and model SMA in mice. We highlight new and emerging insights regarding SMA gained by studying the mice and illustrate how the animals serve as important tools to understand and eventually treat the human disease.

The neuroprotective factor Wld(s) fails to mitigate distal axonal and neuromuscular junction (NMJ) defects in mouse models of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a common autosomal recessive neurodegenerative disorder in humans. Amongst the earliest signs of neurodegeneration are severe and progressive defects of the neuromuscular synapse. These defects, characterized by poor terminal arborization and immature motor endplates, presumably result in a loss of functional synapses. The slow Wallerian degeneration (Wld(s)) mutation in rodents has been shown to have a protective effect on mouse models of motor neuron disease by retarding axonal die-back and preventing neuromuscular synapse loss. In this study we tested the effects of the Wld(s) mutation on the disease phenotype of SMA model mice. Consistent with previous reports, the mutation slows axon and neuromuscular synapse loss following nerve injury in wild-type as well as in SMA mice. However, the synaptic defects found in severely affected SMA patients and model mice persist in the double (Wld(s);SMA) mutants. No delay in disease onset was observed and survival was not significantly altered. Finally, Wld(s) had no effect on the striking phrenic nerve projection defects that we discovered in SMA model mice. Our results indicate that the reported protective effects of Wld(s) are insufficient to mitigate the neuromuscular phenotype due to reduced SMN protein, and that the mechanisms responsible for distal defects of the motor unit in SMA are unlikely to be similar to those causing neurodegeneration in genetic mutants such as the pmn mouse which is partially rescued by the Wld(s) protein.

Limitations and Challenges in Modeling Diseases Involving Spinal Motor Neuron Degeneration in Vitro.

Pathogenic conditions involving degeneration of spinal motor neurons (MNs), such as amyotrophic lateral sclerosis, sarcopenia, and spinal cord injury, mostly occur in individuals whose spinal MNs are fully mature. There is currently no effective treatment to prevent death or promote axonal regeneration of the spinal MNs affected in these patients. To increase our understanding and find a cure for such conditions, easily controllable and monitorable cell culture models allow for a better dissection of certain molecular and cellular events that cannot be teased apart in whole organism models. To date, various types of spinal MN cultures have been described. Yet these models are all based on the use of immature neurons or neurons uncharacterized for their degree of maturity after being isolated and cultured. Additionally, studying only MNs cannot give a comprehensive and complete view of the neurodegenerative processes usually involving other cell types. To date, there is no confirmed in vitro model faithfully emulating disease or injury of the mature spinal MNs. In this review, we summarize the different limitations of currently available culture models, and discuss the challenges that have to be overcome for developing more reliable and translational platforms for the in vitro study of spinal MN degeneration.

Cytoprotective effect of novel histone deacetylase inhibitors against polyglutamine toxicity.

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurological disorder caused by a CAG repeat expansion in the DRPLA gene encoding polyglutamine (polyQ). Although previous experimental studies have demonstrated that histone deacetylase (HDAC) inhibitors are therapeutically active, known HDAC inhibitors have considerable adverse effects clinically. To identify new HDAC inhibitors for the treatment of DRPLA, we evaluated a new series of HDAC inhibitors, N-hydroxycarboxamides, with our drug screening system, which uses neuronal PC12 cells stably transfected with a part of the DRPLA gene. We found that two of four N-hydroxycarboxamides significantly reduced polyQ-induced cell death. The essential structure of these compounds is a hydroxamic acid residue, which is shared with trichostatin A, a known HDAC inhibitor. Although our study showed mild neuroprotective effects, further structural modification of compounds that retain this residue may decrease cytotoxicity and increase protective activity against polyQ toxicity.

Increased vulnerability to L-DOPA toxicity in dopaminergic neurons From VMAT2 heterozygote knockout mice.

Parkinson's disease (PD) is characterized by a preferential loss of dopaminergic neurons in the substantia nigra pars compacta. The etiology of PD remains unclear; however, generation of reactive oxygen species during oxidation of free dopamine (DA) in the cytoplasm might be one of the causes of selective dopaminergic neuron loss in PD. Vesicular monoamine transporter type 2 (VMAT2) proteins in nerve terminals take up and partition DA from neuronal cytoplasm into synaptic vesicles. Alterations of VMAT2 function might therefore cause cytoplasmic accumulation of free DA, which is toxic for dopaminergic neurons. We showed that dopaminergic neurons from VMAT2 heterozygous knockout mice were more vulnerable to the toxic effect of L-3, 4-dihydroxyphenylalanine (L-DOPA, a DA precursor) than those from wild-type mice. Our results suggest that reduction of VMAT2 activity might attenuate the efficacy of L-DOPA therapy for patients with PD.

Humanin attenuates apoptosis induced by DRPLA proteins with expanded polyglutamine stretches.

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal-dominant neurodegenerative disorder caused by expansion of CAG repeats in the DRPLA gene, which codes for a polyglutamine (polyQ) stretch. The expanded polyQs are known to form intracellular aggregates and to confer neurotoxic activity. Recent studies have indicated that activation of apoptosis signal-regulating kinase 1 (ASK1) is involved in polyQ-induced apoptosis. Humanin (HN) is an endogenous peptide that inhibits neuronal cell death caused by mutant Alzheimer's disease genes, and this neuroprotective factor has recently been reported to suppress apoptosis by inhibiting activation of ASK1. To test the anti-ASK1 effect of HN on polyQ neurotoxicity, we constructed neuronal PC12 cells expressing expanded polyQs under the control of the Tet-Off system. Using this cell line, we showed that HN suppresses apoptotic cell death induced by expanded polyQs. However, the suppression was incomplete, suggesting that polyQs also stimulate other pathogenic cascades unrelated to ASK1. We further showed that HN suppresses polyQ aggregate formation. This result implied the possibility that aggregation is also related to the polyQ-mediated cascade involving ASK1 activation. Although the details remain uncertain, our results suggest that ASK1 is potentially involved in pathogenesis of DRPLA and that HN might contribute partially to the suppression of neurodegeneration in polyQ diseases.

Effect of humanin on decreased ATP levels of human lymphocytes harboring A3243G mutant mitochondrial DNA.

Humanin (HN) was originally identified as an endogenous peptide that protects neuronal cells from apoptosis by mutant Alzheimer's disease genes. This 24-residue peptide has been recently shown to suppress apoptosis by interfering with activation of Bcl-2-associated X protein (Bax) in cytosol. In the present study, we showed that HN increases ATP levels in human lymphocytes, muscular TE671 cells, and neural SKN-MC cells, and protects these cells from serum deprivation-induced apoptosis. The suppressed apoptotic death of serum-deprived cells would be explained by the anti-Bax effect of HN; however, HN also increased ATP levels of serum-supplemented cells (non-apoptotic cells), in which Bax is likely to be inactive. This result suggests the presence of a certain mechanism independent of Bax inactivation to increase ATP levels of cells under non-apoptotic condition. By treatment with HN, the ATP levels of lymphocytes from patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) associated with A3243G mutant mtDNA were increased as well, suggesting that HN is able to prevent cells in MELAS from falling into ATP deficiency. Our quantitative PCR findings indicated that the HN-induced increase in ATP may not be a consequence of mitochondrial proliferation, because HN rather suppressed mtDNA replication. This suppression may be important in the treatment of affected cells in MELAS, since the mutant mtDNAs that increase during compensatory mtDNA replication for ATP deficiency cause excessive formation of reactive oxygen species, leading to further energy crisis. We thus propose that HN, which increases cellular ATP levels without inducing mtDNA replication, may be suited for the treatment of MELAS.

Lack of association between polymorphic microsatellites of the VMAT2 gene and Parkinson's disease in Japan.

The etiology of Parkinson's disease (PD) remains unclear; however, generation of reactive oxygen species during oxidation of dopamine (DA) could be one of the factors leading to selective loss of nigral dopaminergic neurons in PD. Vesicular monoamine transporter type 2 (VMAT2) proteins in nerve terminals uptake and partition DA from neuronal cytoplasm into synaptic vesicles. Therefore, alterations of VMAT2 function may cause cytoplasmic accumulation of free DA, toxic to dopaminergic neurons. Upstream of a putative promoter region of the VMAT2 gene, there exist polymorphic sequences consisting of two microsatellites, (CA)n and (GA)n. We performed a case-control study of this polymorphic region to determine whether the VMAT2 gene is related to PD. We found six genotypes; however, there was no significant difference in the allele frequencies between patients with PD and control subjects. Our data suggest that the polymorphic region of the VMAT2 gene studied here is not closely related to PD.

Spectrum of neuropathophysiology in spinal muscular atrophy type I.

Neuropathologic findings within the central and peripheral nervous systems in patients with spinal muscular atrophy type I (SMA-I) were examined in relation to genetic, clinical, and electrophysiologic features. Five infants representing the full clinical spectrum of SMA-I were examined clinically for compound motor action potential amplitude and SMN2 gene copy number; morphologic analyses of postmortem central nervous system, neuromuscular junction, and muscle tissue samples were performed and SMN protein was assessed in muscle samples. The 2 clinically most severely affected patients had a single copy of the SMN2 gene; in addition to anterior horn cells, dorsal root ganglia, and thalamus, neuronal degeneration in them was widespread in the cerebral cortex, basal ganglia, pigmented nuclei, brainstem, and cerebellum. Two typical SMA-I patients and a milder case each had 2 copies of the SMN2 gene and more restricted neuropathologic abnormalities. Maturation of acetylcholine receptor subunits was delayed and the neuromuscular junctions were abnormally formed in the SMA-I patients. Thus, the neuropathologic findings in human SMA-I are similar to many findings in animal models; factors other than SMN2 copy number modify disease severity. We present a pathophysiologic model for SMA-I as a protein deficiency disease affecting a neuronal network with variable clinical thresholds. Because new treatment strategies improve survival of infants with SMA-I, a better understanding of these factors will guide future treatments.

Humanin inhibits cell death of serum-deprived PC12h cells.

Humanin (HN) and S14G HN (HNG) are recently discovered polypeptides that rescue cells from death induced by multiple different types of familial Alzheimer's disease genes and by amyloid-beta. However, the cytoprotective activity of these peptides against other cell death-inducing stimuli remains unclear. In this study, we demonstrated, using three different methods (MTS assay, caspase-3 assay, and detection of DNA fragmentation), that both HN and HNG protect PC12 cells from death elicited by serum deprivation. This implies the potential of the peptides to rescue cells from a broad spectrum, if not all, of cell death-inducing factors. Further investigations on HN may lead the possible application of this peptide as therapeutic agent for the treatment of other neurodegenerative diseases.