Robust Comparison of Protein Levels Across Tissues and Throughout Development Using Standardized Quantitative Western Blotting

Long-term muscle-specific overexpression of DOK7 in mice using AAV9-tMCK-DOK7

Neuromuscular junction (NMJ) dysfunction underlies several diseases, including congenital myasthenic syndromes (CMSs) and motor neuron disease (MND). Molecular pathways governing NMJ stability are therefore of interest from both biological and therapeutic perspectives. Muscle-specific kinase (MuSK) is necessary for the formation and maintenance of post-synaptic elements of the NMJ, and downstream of tyrosine kinases 7 (DOK7) is crucial for activation of the MuSK pathway. Overexpression of DOK7 using AAV9 has been shown to ameliorate neuromuscular pathology in pre-clinical disease models of CMS and MND. However, long-term consequences of DOK7 expression have been sparsely investigated and targeted overexpression of DOK7 in skeletal muscle yet to be established. Here, we developed and characterized a novel AAV9-DOK7 facilitating forced expression of DOK7 under a skeletal muscle-specific promoter. AAV9-tMCK-DOK7 was systemically delivered to newborn mice that were monitored over 6 months. DOK7 overexpression was restricted to skeletal muscles. Body weight, blood biochemistry, and histopathological assessments were unaffected by AAV9-tMCK-DOK7 treatment. In contrast, forced expression of DOK7 resulted in enlargement of both the pre- and post-synaptic components of the NMJ, without causing denervation. We conclude that muscle-specific DOK7 overexpression can be achieved in a safe manner, with the capacity to target NMJs in vivo.

Improving rigor and reproducibility in western blot experiments with the blotRig analysis software

Western blot is a popular biomolecular analysis method for measuring the relative quantities of independent proteins in complex biological samples. However, variability in quantitative western blot data analysis poses a challenge in designing reproducible experiments. The lack of rigorous quantitative approaches in current western blot statistical methodology may result in irreproducible inferences. Here we describe best practices for the design and analysis of western blot experiments, with examples and demonstrations of how different analytical approaches can lead to widely varying outcomes. To facilitate best practices, we have developed the blotRig tool for designing and analyzing western blot experiments to improve their rigor and reproducibility. The blotRig application includes functions for counterbalancing experimental design by lane position, batch management across gels, and analytics with covariates and random effects.

Pre-natal manifestation of systemic developmental abnormalities in spinal muscular atrophy

Spinal muscular atrophy (SMA) is a neuromuscular disease caused by mutations in survival motor neuron 1 (SMN1). SMN-restoring therapies have recently emerged; however, preclinical and clinical studies revealed a limited therapeutic time window and systemic aspects of the disease. This raises a fundamental question of whether SMA has presymptomatic, developmental components to disease pathogenesis. We have addressed this by combining micro-computed tomography (μCT) and comparative proteomics to examine systemic pre-symptomatic changes in a prenatal mouse model of SMA. Quantitative μCT analyses revealed that SMA embryos were significantly smaller than littermate controls, indicative of general developmental delay. More specifically, cardiac ventricles were smaller in SMA hearts, whilst liver and brain remained unaffected. In order to explore the molecular consequences of SMN depletion during development, we generated comprehensive, high-resolution, proteomic profiles of neuronal and non-neuronal organs in SMA mouse embryos. Significant molecular perturbations were observed in all organs examined, highlighting tissue-specific prenatal molecular phenotypes in SMA. Together, our data demonstrate considerable systemic changes at an early, presymptomatic stage in SMA mice, revealing a significant developmental component to SMA pathogenesis.

Network Pharmacology Analysis of the Effects of Achyranthis Bidentatae Radix Plus Semen Vaccariae on Migraine-Induced Erectile Dysfunction

BACKGROUND AND AIM

Achyranthis Bidentatae Radix plus Semen Vaccariae are traditional Chinese medicines, which have been widely applied in the treatment of migraine and erectile dysfunction (ED) for many years. The aim of this study is to verify the effect of Achyranthis Bidentatae Radix plus Semen Vaccariae in improving migraine-induced ED and explore its potential mechanism.

METHODS

Key targets and signaling pathways of Achyranthis Bidentatae Radix plus Semen Vaccariae in migraine-induced erectile dysfunction treatment were predicted by network pharmacology. A rat model of migraine was established by nitroglycerin injection. Apomorphine was injected into rats to screen the migraine-induced erectile dysfunction model, Achyranthis Bidentatae Radix-Semen Vaccariae granule suspension administered, and erectile function evaluated. Hematoxylin and eosin staining was used to compare the histological structure of the penile tissue, while RT-qPCR and Western blotting were used to determine mRNA and protein levels, respectively.

RESULTS

Screening allowed us to identify common targets for migraine and ED; the signaling pathway exhibiting the greatest change the Myosin light chain kinase- Calcium (MLCK-CaM) signal pathway. From Western blotting and RT-qPCR, we found that the levels of MLCK mRNA and protein in rats from Group B rats were significantly higher (P<0.05) than those in Groups A and C. Furthermore, the mRNA and protein levels of CaM were significantly higher in Group B (P<0.05) than in Groups A and C.

CONCLUSION

Data indicate that the regulatory effects of Achyranthis Bidentatae Radix plus Semen Vaccariae on migraine-induced ED in a rat model are mediated by the MLCK-CaM signaling pathway.

Effects of Diabetes Mellitus on Sperm Quality in the Db/Db Mouse Model and the Role of the FoxO1 Pathway

Background

Studies have shown that diabetes mellitus (DM) has a negative impact on male reproductive function, which may lead to changes in the testis and epididymis and a decline in semen quality.

Material/Methods

We performed animal experiments with 6 diabetic db/db mice as the model group (group B) and 6 C57BL/6J mice as the control group (group A). After adaptive feeding for 7 days, the sperm quality of each group was measured. Concurrently, the morphology of the mouse testis was observed by hematoxylin-eosin (H&E) staining. The expression of the PI3K, Akt, FoxO1, FasL, IL-6, and Stat3 proteins and mRNAs in the testicular tissue was detected by western blotting and RT-qPCR.

Results

The number of spermatozoa and sperm motility of group A was significantly higher than that of group B (P<0.05). H&E staining of the testicular tissue showed the seminiferous tubules in group B mice were damaged to varying degrees and the seminiferous tubules were sparsely arranged. Compared with those of group A, the expression levels of PI3K, Akt, and Stat3 proteins and mRNAs in group B were significantly lower (P<0.05), while the expression levels of FoxO1, FasL, and IL-6 proteins and mRNAs in group B mice were significantly higher (P<0.05).

Conclusions

This study demonstrated that DM inhibited the expression of PI3K, Akt, and Stat3 proteins and mRNAs in the FoxO1 pathway and promoted the expression of FoxO1, FasL, and IL-6 proteins and mRNAs, leading to abnormal apoptosis of testicular tissue cells and functional damage, and eventually spermatogenic dysfunction.

Effect of Asthma on Erectile Dysfunction in Rats as Determined by Biological Network Analysis

Background

We explored the effect of asthma on erectile dysfunction (ED) and the effects of the expression of related proteins.

Material/Methods

We used a bioinformatics database to predict the targets and pathways associated with asthma and ED. The rat model of asthma was caused by an ovalbumin solution. The number of erections in 30 min was observed by injecting apomorphine into the neck at a dose of 100 μg/kg. Rats with no erection were regarded as the model group (group B), and the previous random 6 normal rats were regarded as the control group (group A). We used hematoxylin and eosin (HE) to compare the tissue structure of the cavernous body of the penis. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to determine the expression levels of insulin (INS), interleukin 6 (IL6), albumin (ALB), tumor necrosis factor (TNF), and vascular endothelial growth factor A (VEGFA) at both the protein and messenger ribonucleic acid (mRNA) levels.

Results

HE staining results show that compared with group A, the blood sinus distribution of the cavernous body in group B was disordered, and the density of endothelial cells and smooth muscle cells decreased significantly. Western blotting and RT-qPCR showed that the levels of IL6, TNF, and VEGFA protein and mRNA in group B were significantly higher (P<0.05) than those in group A. The levels of INS and ALB were not significantly different between the 2 groups.

Conclusions

On the basis of the results, we found that asthma caused pathological changes in the penises of rats and led to reduced erectile function via changes in the expression of IL6, TNF, and VEGFA proteins.

SMN-primed ribosomes modulate the translation of transcripts related to spinal muscular atrophy

The contribution of ribosome heterogeneity and ribosome-associated proteins to the molecular control of proteomes in health and disease remains unclear. Here, we demonstrate that survival motor neuron (SMN) protein-the loss of which causes the neuromuscular disease spinal muscular atrophy (SMA)-binds to ribosomes and that this interaction is tissue-dependent. SMN-primed ribosomes are preferentially positioned within the first five codons of a set of mRNAs that are enriched for translational enhancer sequences in the 5' untranslated region (UTR) and rare codons at the beginning of their coding sequence. These SMN-specific mRNAs are associated with neurogenesis, lipid metabolism, ubiquitination, chromatin regulation and translation. Loss of SMN induces ribosome depletion, especially at the beginning of the coding sequence of SMN-specific mRNAs, leading to impairment of proteins that are involved in motor neuron function and stability, including acetylcholinesterase. Thus, SMN plays a crucial role in the regulation of ribosome fluxes along mRNAs encoding proteins that are relevant to SMA pathogenesis.

Simplified detection of polyhistidine-tagged proteins in gels and membranes using a UV-excitable dye and a multiple chelator head pair

The polyhistidine tag (His-tag) is one of the most popular protein tags used in the life sciences. Traditionally, the detection of His-tagged proteins relies on immunoblotting with anti-His antibodies. This approach is laborious for certain applications, such as protein purification, where time and simplicity are critical. The His-tag can also be directly detected by metal ion-loaded nickel-nitrilotriacetic acid-based chelator heads conjugated to fluorophores, which is a convenient alternative method to immunoblotting. Typically, such chelator heads are conjugated to either green or red fluorophores, the detection of which requires specialized excitation sources and detection systems. Here, we demonstrate that post-run staining is ideal for His-tag detection by metal ion-loaded and fluorescently labeled chelator heads in PAGE and blot membranes. Additionally, by comparing the performances of different chelator heads, we show how differences in microscopic affinity constants translate to macroscopic differences in the detection limits in environments with limited diffusion, such as PAGE. On the basis of these results, we devise a simple approach, called UVHis-PAGE, that uses metal ion-loaded and fluorescently labeled chelator heads to detect His-tagged proteins in PAGE and blot membranes. Our method uses a UV transilluminator as an excitation source, and the results can be visually inspected by the naked eye.