How plants recognize pathogens and activate defense is still mysterious. Direct interaction between pathogen avirulence (Avr) proteins and plant disease resistance proteins is the exception rather ...than the rule. During infection, Cladosporium fulvum secretes Avr2 protein into the apoplast of tomato leaves and, in the presence of the extracellular leucine-rich repeat receptor-like Cf-2 protein, triggers a hypersensitive response (HR) that also requires the extracellular tomato cysteine protease Rcr3. We show here that Avr2 binds and inhibits Rcr3 and propose that the Rcr3-Avr2 complex enables the Cf-2 protein to activate an HR.
Astrocytes produce an assortment of signals that promote neuronal maturation according to a precise developmental timeline. Is this orchestrated timing and signaling altered in human ...neurodevelopmental disorders? To address this question, the astroglial lineage was investigated in two model systems of a developmental disorder with intellectual disability caused by mutant Harvey rat sarcoma viral oncogene homolog (HRAS) termed Costello syndrome: mutant HRAS human induced pluripotent stem cells (iPSCs) and transgenic mice. Human iPSCs derived from patients with Costello syndrome differentiated to astroglia more rapidly in vitro than those derived from wild-type cell lines with normal HRAS, exhibited hyperplasia, and also generated an abundance of extracellular matrix remodeling factors and proteoglycans. Acute treatment with a farnesyl transferase inhibitor and knockdown of the transcription factor SNAI2 reduced expression of several proteoglycans in Costello syndrome iPSC-derived astrocytes. Similarly, mice in which mutant HRAS was expressed selectively in astrocytes exhibited experience-independent increased accumulation of perineuronal net proteoglycans in cortex, as well as increased parvalbumin expression in interneurons, when compared to wild-type mice. Our data indicate that astrocytes expressing mutant HRAS dysregulate cortical maturation during development as shown by abnormal extracellular matrix remodeling and implicate excessive astrocyte-to-neuron signaling as a possible drug target for treating mental impairment and enhancing neuroplasticity.
New breeding programs are faced with many challenges including evaluation of unknown germplasm, initiation of breeding populations that will satisfy short‐ and long‐term breeding goals, and ...implementation of efficient phenotyping strategies for multiple traits. Genomic selection (GS) is a potentially valuable tool for recently established breeding programs to quickly accelerate genetic gain. Genomic selection on selection index (SI) values may increase gain over phenotypic selection but empirical studies remain limited. We compared gain in overall SI value for height, heading date, preharvest sprouting (PHS) resistance, and spot blotch resistance and component traits in two cycles of GS with one round of phenotypic selection (PS) in two‐row spring malting barley (Hordeum vulgare L.). Higher realized gain for SI value, height, and PHS was observed with GS compared with PS but GS did not result in significant gain for heading date and spot blotch. Genetic variances for height and heading date, which had small index weights, were not reduced with GS but variances were substantially reduced for heavily weighted PHS and correlated seed germination traits. Inbreeding was increased by GS compared with PS but restricted mating of high breeding value individuals limited potential inbreeding. Our results indicate GS is a useful method to improve selection on index values with different weights.
Core Ideas
Two genomic selection cycles resulted in higher SI gain than phenotypic selection
Genetic gain and decrease in variance for component traits were proportional to index weights
Genomic selection improved genetic gain for a sparsely phenotyped trait
Prediction of trait values in plant breeding populations typically relies on assumptions about marker effect homogeneity across populations. Evidence is presented for winter malting barley (Hordeum ...vulgare L.) germination traits that a single, causative, large‐effect gene in the Seed dormancy 1 region on Chromosome 5H, HvAlaAT1 (Qsd1), leads to heterogeneous estimated marker effects genome wide between groups of otherwise related individuals carrying different Qsd1 alleles. This led to reduced prediction accuracy across alleles when a model was trained either on individuals carrying both alleles or one allele. Several genomic prediction models were tested to increase prediction accuracy within the Qsd1 allele groups. Small gains (5–12%) in prediction accuracy were realized using structured genomic best linear unbiased predictor models when information about the Qsd1 allele was used to stratify the population. We concluded that a single large‐effect locus can lead to heterogeneous marker effects in the same breeding family. Variance partitioning based on large‐effect loci can be used to inform best practices in designing genomic prediction models; however, there are likely few cases for which it may be practical to do this. For malting barley, if germination traits are highly associated with malting quality traits, then similar steps should be considered for malting quality trait prediction.
Core Ideas
A single large‐effect seed dormancy locus leads to genome‐wide marker effect heterogeneity.
Prediction accuracy between individuals with different dormancy alleles is lower than within allele prediction.
A structured GBLUP model can be used to increase prediction accuracy across all individuals.
The effects of large‐effect loci on allele substitution should be accessed when present in a population.
Duchenne muscular dystrophy (DMD) is a devastating neuromuscular disease caused by mutations in the gene encoding dystrophin. Loss of dystrophin results in reduced sarcolemmal integrity and increased ...susceptibility to muscle damage. The α₇β₁-integrin is a laminin-binding protein up-regulated in the skeletal muscle of DMD patients and in the mdx mouse model. Transgenic overexpression of the α₇-integrin alleviates muscle disease in dystrophic mice, making this gene a target for pharmacological intervention. Studies suggest laminin may regulate α₇-integrin expression. To test this hypothesis, mouse and human myoblasts were treated with laminin and assayed for α₇-integrin expression. We show that laminin-111 (α₁, β₁, γ₁), which is expressed during embryonic development but absent in normal or dystrophic skeletal muscle, increased α₇-integrin expression in mouse and DMD patient myoblasts. Injection of laminin-111 protein into the mdx mouse model of DMD increased expression of α₇-integrin, stabilized the sarcolemma, restored serum creatine kinase to wild-type levels, and protected muscle from exercised-induced damage. These findings demonstrate that laminin-111 is a highly potent therapeutic agent for the mdx mouse model of DMD and represents a paradigm for the systemic delivery of extracellular matrix proteins as therapies for genetic diseases.
Merosin-deficient congenital muscular dystrophy type 1A (MDC1A) is a lethal muscle-wasting disease that is caused by mutations in the LAMA2 gene, resulting in the loss of laminin-α2 protein. MDC1A ...patients exhibit severe muscle weakness from birth, are confined to a wheelchair, require ventilator assistance, and have reduced life expectancy. There are currently no effective treatments or cures for MDC1A. Laminin-α2 is required for the formation of heterotrimeric laminin-211 (ie, α2, β1, and γ1) and laminin-221 (ie, α2, β2, and γ1), which are major constituents of skeletal muscle basal lamina. Laminin-111 (ie, α1, β1, and γ1) is the predominant laminin isoform in embryonic skeletal muscle and supports normal skeletal muscle development in laminin-α2–deficient muscle but is absent from adult skeletal muscle. In this study, we determined whether treatment with Engelbreth-Holm-Swarm–derived mouse laminin-111 protein could rescue MDC1A in the dy W−/− mouse model. We demonstrate that laminin-111 protein systemically delivered to the muscles of laminin-α2–deficient mice prevents muscle pathology, improves muscle strength, and dramatically increases life expectancy. Laminin-111 also prevented apoptosis in laminin-α2–deficient mouse muscle and primary human MDC1A myogenic cells, which indicates a conserved mechanism of action and cross-reactivity between species. Our results demonstrate that laminin-111 can serve as an effective protein substitution therapy for the treatment of muscular dystrophy in the dy W−/− mouse model and establish the potential for its use in the treatment of MDC1A.
Abstract Issues related to the intra-cerebral delivery of glial cell line-derived neurotrophic factor (GDNF) have hampered its progression as a neuroprotective therapy for Parkinson's disease. Ex ...vivo gene therapy, where cells are virally transduced in vitro to produce a specific protein, may circumvent some of the problems associated with direct delivery of this neurotrophin to the brain. In this regard, bone marrow-derived mesenchymal stem cells (MSCs) offer an ideal cell source for ex vivo gene therapy because they are easily isolated from autologous sources, they are amenable to viral transduction and expansion in vitro, and they are hypoimmunogenic and non-tumourigenic in the brain. Thus the aim of this study was to determine the neurotrophic capacity of GDNF-transduced MSCs in a rat model of Parkinson's disease. Rats received intrastriatal transplants of GDNF-transduced MSCs 4 days prior to induction of an intrastriatal 6-hydroxydopamine lesion. Quantitative tyrosine hydroxylase immunohistochemical staining revealed that GDNF-transduced MSCs were capable of inducing a pronounced local trophic effect in the denervated striatum which was evident by sprouting from the remaining dopaminergic terminals towards the neurotrophic milieu created by the transplanted cells. This strengthens the candidacy of MSCs as vehicles to deliver neurotrophins to the Parkinsonian brain.
The ankle joint is frequently involved in juvenile idiopathic arthritis (JIA), but it is unclear whether this is predominantly due to synovitis, tenosynovitis, or both. We performed clinic-based ...ultrasound examination to assess the prevalence of synovitis and tenosynovitis in children with JIA felt clinically to have active inflammatory disease of the ankle.
Thirty-four patients with 49 clinically swollen ankles were studied (19 polyarticular JIA, 13 oligoarticular JIA, 1 systemic JIA, 1 psoriatic JIA). All cases had at least one clinically swollen ankle joint. The children were assessed clinically and had ultrasound examination during routine clinic appointments.
We found 71% of ankles had tenosynovitis and 39% had tenosynovitis alone. Only 29% of swollen ankles had a tibiotalar effusion alone. We found 33% had both tenosynovitis and a tibiotalar effusion. When results were analyzed by JIA subtype, we found 81% of oligoarticular JIA ankles had medial ankle tenosynovitis but only 19% had tibiotalar effusion alone. There was a significant difference between JIA subgroups for the frequency of occurrence of medial ankle tenosynovitis (p = 0.048) and lateral ankle tenosynovitis (p = 0.001).
The tibiotalar joint was not involved in 39% of the swollen ankles; and tenosynovitis, sometimes in isolation, was the dominant finding. This has implications for therapeutic intervention and also for an improved classification of children with JIA, especially with ankle involvement.
Abstract The transected rat thoracic (T9/10 ) spinal cord model is a platform for quantitatively comparing biodegradable polymer scaffolds. Schwann cell-loaded scaffolds constructed from poly (lactic ...co-glycolic acid) (PLGA), poly(ε-caprolactone fumarate) (PCLF), oligo(polyethylene glycol) fumarate (OPF) hydrogel or positively charged OPF (OPF+) hydrogel were implanted into the model. We demonstrated that the mechanical properties (3-point bending and stiffness) of OPF and OPF + hydrogels closely resembled rat spinal cord. After one month, tissues were harvested and analyzed by morphometry of neurofilament-stained sections at rostral, midlevel, and caudal scaffold. All polymers supported axonal growth. Significantly higher numbers of axons were found in PCLF ( P < 0.01) and OPF+ ( P < 0.05) groups, compared to that of the PLGA group. OPF + polymers showed more centrally distributed axonal regeneration within the channels while other polymers (PLGA, PCLF and OPF) tended to show more evenly dispersed axons within the channels. The centralized distribution was associated with significantly more axons regenerating ( P < 0.05). Volume of scar and cyst rostral and caudal to the implanted scaffold was measured and compared. There were significantly smaller cyst volumes in PLGA compared to PCLF groups. The model provides a quantitative basis for assessing individual and combined tissue engineering strategies.
Biodegradable polymer scaffolds provide an excellent approach to quantifying critical factors necessary for restoration of function after a transection spinal cord injury. Neural stem cells (NSCs) ...and Schwann cells (SCs) support axonal regeneration. This study examines the compatibility of NSCs and SCs with the poly-lactic-co-glycolic acid polymer scaffold and quantitatively assesses their potential to promote regeneration after a spinal cord transection injury in rats. NSCs were cultured as neurospheres and characterized by immunostaining for nestin (NSCs), glial fibrillary acidic protein (GFAP) (astrocytes), betaIII-tubulin (immature neurons), oligodendrocyte-4 (immature oligodendrocytes), and myelin oligodendrocyte (mature oligodendrocytes), while SCs were characterized by immunostaining for S-100. Rats with transection injuries received scaffold implants containing NSCs (n=17), SCs (n=17), and no cells (control) (n=8). The degree of axonal regeneration was determined by counting neurofilament-stained axons through the scaffold channels 1 month after transplantation. Serial sectioning through the scaffold channels in NSC- and SC-treated groups revealed the presence of nestin, neurofilament, S-100, and betaIII tubulin-positive cells. GFAP-positive cells were only seen at the spinal cord-scaffold border. There were significantly more axons in the NSC- and SC- treated groups compared to the control group. In conclusion, biodegradable scaffolds with aligned columns seeded with NSCs or SCs facilitate regeneration across the transected spinal cord. Further, these multichannel biodegradable polymer scaffolds effectively serve as platforms for quantitative analysis of axonal regeneration.
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