Comparative genome analysis of plant ascomycete fungal pathogens with different lifestyles reveals distinctive virulence strategies

Background: Pathogens have evolved diverse lifestyles and adopted pivotal new roles in both natural ecosystems and human environments. However, the molecular mechanisms underlying their adaptation to new lifestyles are obscure. Comparative genomics was adopted to determine distinct strategies of plant ascomycete fungal pathogens with different lifestyles and to elucidate their distinctive virulence strategies. Results: We found that plant ascomycete biotrophs exhibited lower gene gain and loss events and loss of CAZyme-encoding genes involved in plant cell wall degradation and biosynthesis gene clusters for the production of secondary metabolites in the genome. Comparison with the candidate effectome detected distinctive variations between plant biotrophic pathogens and other groups (including human, necrotrophic and hemibiotrophic pathogens). The results revealed the biotroph-specific and lifestyle-conserved candidate effector families. These data have been configured in web-based genome browser applications for public display (http://lab.malab.cn/soft/PFPG). This resource allows researchers to profile the genome, proteome, secretome and effectome of plant fungal pathogens. Conclusions: Our findings demonstrated different genome evolution strategies of plant fungal pathogens with different lifestyles and explored their lifestyle-conserved and specific candidate effectors. It will provide a new basis for discovering the novel effectors and their pathogenic mechanisms

Relationship of Klotho with cognition and dementia: Results from the NHANES 2011–2014 and Mendelian randomization study

Abstract The relationships of Klotho levels with cognition and dementia are poorly understood. This study aimed to investigate the association between Klotho levels and cognitive function and to determine causality between Klotho and dementia using Mendelian randomization (MR). Based on data from the National Health and Nutrition Survey (NHANES) 2011–2014, this study consisted of 1875 older adults aged 60–79 years. Cognitive function was assessed by the digit symbol substitution test (DSST). We performed weighted multivariable-adjusted linear regression to assess the association between Klotho concentrations and cognitive function. Then, 2-sample MR was conducted to assess the causal relationship between Klotho and dementia. The inverse variance weighted (IVW) method was used as the primary analysis. We observed a positive association between serum Klotho concentrations and the results of the Digit Symbol Substitution test (DSST) (T2: β 2.16, 95% CI: 0.30–4.01, P = 0.03, T3: β 2.48, 95% CI: 0.38–4.57, P = 0.02) after adjusting for the covariates. Moreover, there was also a potential nonlinear relationship between Klotho and DSST. The IVW method showed that genetically predicted high Klotho levels were not significantly associate with any type of dementia, including Alzheimer’s disease (OR = 1.03, 95% CI: 0.96–1.10, P = 0.46), vascular dementia (OR = 1.04, 95% CI: 0.87–1.25, P = 0.66), frontotemporal dementia (OR = 0.73, 95% CI: 0.47–1.14, P = 0.16), or dementia with Lewy bodies (OR = 1.03, 95% CI: 0.87–1.23, P = 0.73). In the cross-sectional observational study, Klotho and cognitive function were significantly correlated; however, findings from MR studies did not indicate a causal relationship between Klotho and dementia

A Single Injection of Recombinant Adeno-Associated Virus into the Lumbar Cistern Delivers Transgene Expression Throughout the Whole Spinal Cord

The lack of methods to deliver transgene expression in spinal cord has hampered investigation of gene function and therapeutic targets for spinal cord diseases. Here, we report that a single intrathecal injection of recombinant adeno-associated virus rhesus-10 (rAAVrh10) into the lumbar cistern led to transgene expression in 60 to 90 % of the cells in the spinal cord. The transgene was expressed in all cell types, including neurons, glia, ependymal cells, and endothelial cells. Additionally, the transgene was expressed in some brain areas up to the frontal cortex and the olfactory bulb. The rAAV was distributed predominantly in the spinal cord, where its genome copy was over ten times that of the peripheral organs. Compared with intravenous injection, another method for rAAV delivery to the broad central nervous system (CNS), the intrathecal injection reduced the dosage of rAAV required to achieve similar or higher levels of transgene expression in the CNS by ~100-fold. Finally, the transduced areas were co-localized with the perivascular spaces of Virchow-Robin, from which the rAAV spreads further into the CNS parenchyma, thus suggesting that rAAV penetrated the CNS parenchyma through this pathway. Taken together, we have defined a fast and efficient method to deliver widespread transgene expression in mature spinal cord in mice. This method can be applied to stably overexpress or silence gene expression in the spinal cord to investigate gene functions in mammalian CNS. Additionally, this method can be applied to validate therapeutic targets for spinal cord diseases

Factors Related to Plasma Homocysteine Concentration in Young Adults: A Retrospective Study Based on Checkup Populations

The distribution profile of plasma homocysteine (Hcy) in young adults and its related factors are not well understood. We performed a generalized estimating equations (GEE) analysis for plasma-Hcy-correlated factors in 2436 young adults, aged 20–39 years, from a health checkup population. We observed that the mean Hcy concentration in males (16.7 ± 10.3 μmol/L) was significantly higher than that in females (10.3 ± 4.0 μmol/L), and hyperhomocysteinemia (HHcy) prevalence in males was 5.37 times than that in females (33.3% vs. 6.2%). A GEE analysis stratified by sex indicated that age (B = −0.398, p p = 0.043) were negatively correlated, while BMI (B = 0.400, p = 0.042) was positively correlated, with the Hcy level in young males. ALT (B = −0.021, p = 0.033), LDL-C (B = −1.198, p p = 0.006) were negatively correlated, while AST (B = 0.022, p = 0.048), CREA (B = 0.035, p p = 0.003) and TG (B = 1.042, p < 0.001) were positively correlated, with the Hcy level in young females. These results suggest that young males have a significantly higher plasma Hcy level and HHcy prevalence than young females; therefore, more attention should be paid to the reason for and effect of the higher HHcy prevalence in young males

Decreased GLT-1 and increased SOD1 and HO-1 expression in astrocytes contribute to lumbar spinal cord vulnerability of SOD1-G93A transgenic mice

AbstractThe SOD1-G93A transgenic mouse is a widely used ALS model, but the death of lower motor neurons is the hallmark. Here, we show that the SOD1-G93A transgene and HO-1 are preferentially over-expressed in the lumbar spinal cord, particularly in the activated astrocytes of the transgenic mice. We also show down-regulation of GLT-1 in spite of the proliferating astrocytes. However, GLT-1, SOD1-G93A transgene and HO-1 expression were not obviously changed in the motor cortex. Our data link spinal cord vulnerability to relatively decreased expression of GLT-1, and high expression of the transgene and HO-1 in astrocytes in SOD1-G93A transgenic mice

Widespread spinal cord transduction by intrathecal injection of rAAV delivers efficacious RNAi therapy for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) causes motor neuron degeneration and paralysis. No treatment can significantly slow or arrest the disease progression. Mutations in the SOD1 gene cause a subset of familial ALS by a gain of toxicity. In principle, these cases could be treated with RNAi that destroys the mutant mRNA, thereby abolishing the toxic protein. However, no system is available to efficiently deliver the RNAi therapy. Recombinant adenoassociated virus (rAAV) is a promising vehicle due to its long-lasting gene expression and low toxicity. However, ALS afflicts broad areas of the central nervous system (CNS). A lack of practical means to spread rAAV broadly has hindered its application in treatment of ALS. To overcome this barrier, we injected several rAAV serotypes into the cerebrospinal fluid. We found that some rAAV serotypes such as rAAVrh10 and rAAV9 transduced cells throughout the length of the spinal cord following a single intrathecal injection and in the broad forebrain following a single injection into the third ventricle. Furthermore, a single intrathecal injection of rAAVrh10 robustly transduced motor neurons throughout the spinal cord in a non-human primate. These results suggested a therapeutic potential of this vector for ALS. To test this, we injected a rAAVrh10 vector that expressed an artificial miRNA targeting SOD1 into the SOD1G93A mice. This treatment knocked down the mutant SOD1 expression and slowed the disease progression. Our results demonstrate the potential of rAAVs for delivering gene therapy to treat ALS and other diseases that afflict broad areas of the CNS

Low-level overexpression of wild type TDP-43 causes late-onset, progressive neurodegeneration and paralysis in mice [preprint]

Modestly increased expression of transactive response DNA binding protein (TDP-43) gene have been reported in amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and other neuromuscular diseases. However, whether this modest elevation triggers neurodegeneration is not known. Although high levels of TDP-43 overexpression have been modeled in mice and shown to cause early death, models with low-level overexpression that mimic the human condition have not been established. In this study, transgenic mice overexpressing wild type TDP-43 at less than 60% above the endogenous CNS levels were constructed, and their phenotypes analyzed by a variety of techniques, including biochemical, molecular, histological, behavioral techniques and electromyography. The TDP-43 transgene was expressed in neurons, astrocytes, and oligodendrocytes in the cortex and predominantly in astrocytes and oligodendrocytes in the spinal cord. The mice developed a reproducible progressive weakness ending in paralysis in mid-life. Detailed analysis showed ∼30% loss of large pyramidal neurons in the layer V motor cortex; in the spinal cord, severe demyelination was accompanied by oligodendrocyte injury, protein aggregation, astrogliosis and microgliosis, and elevation of neuroinflammation. Surprisingly, there was no loss of lower motor neurons in the lumbar spinal cord despite the complete paralysis of the hindlimbs. However, denervation was detected at the neuromuscular junction. These results demonstrate that low-level TDP-43 overexpression can cause diverse aspects of ALS, including late-onset and progressive motor dysfunction, neuroinflammation, and neurodegeneration. Our findings suggest that persistent modest elevations in TDP-43 expression can lead to ALS and other neurological disorders involving TDP-43 proteinopathy. Because of the predictable and progressive clinical paralytic phenotype, this transgenic mouse model will be useful in preclinical trial of therapeutics targeting neurological disorders associated with elevated levels of TDP-43

Global CNS transduction of adult mice by intravenously delivered rAAVrh.8 and rAAVrh.10 and nonhuman primates by rAAVrh.10

Some recombinant adeno-associated viruses (rAAVs) can cross the neonatal blood-brain barrier (BBB) and efficiently transduce cells of the central nervous system (CNS). However, in the adult CNS, transduction levels by systemically delivered rAAVs are significantly reduced, limiting their potential for CNS gene therapy. Here, we characterized 12 different rAAVEGFPs in the adult mouse CNS following intravenous delivery. We show that the capability of crossing the adult BBB and achieving widespread CNS transduction is a common character of AAV serotypes tested. Of note, rAAVrh.8 is the leading vector for robust global transduction of glial and neuronal cell types in regions of clinical importance such as cortex, caudate-putamen, hippocampus, corpus callosum, and substantia nigra. It also displays reduced peripheral tissue tropism compared to other leading vectors. Additionally, we evaluated rAAVrh.10 with and without microRNA (miRNA)-regulated expressional detargeting from peripheral tissues for systemic gene delivery to the CNS in marmosets. Our results indicate that rAAVrh.8, along with rh.10 and 9, hold the best promise for developing novel therapeutic strategies to treat neurological diseases in the adult patient population. Additionally, systemically delivered rAAVrh.10 can transduce the CNS efficiently, and its transgene expression can be limited in the periphery by endogenous miRNAs in adult marmosets