Comparison of the sensitivity of Western blotting between PVDF and NC membranes

Effect and mechanism of miRNA-144-5p-regulated autophagy in older adults with Sarcopenia

BACKGROUND

Advanced aging invariably triggers an overabundance of apoptosis, stemming from diminished autophagy or a disarray in cellular autophagic processes. This, in turn, leads to an accelerated breakdown of muscle proteins, which exacerbates the ongoing deterioration of skeletal muscle and intensifies the severity of senile sarcopenia. This study aimed to investigate the role and mechanism of miRNA-regulated autophagy in senile sarcopenia.

METHODS

The miRNAs associated with sarcopenia were screened, and the target genes of significant miRNAs were predicted. The effects of significantly differentially expressed miRNA-144-5p on cell aging and autophagy were validated in vivo and in vitro.

RESULTS

The inhibition of miR-144-5p enhanced the multiplication of mouse myoblasts, increased the expression of MHC and autophagic markers LC3II/LC3I and Beclin-1, facilitated the formation of autophagosomes in mouse myoblasts, and reduced the number of aging cells and the expression of senescence-related proteins acetylated p53, p53, and p21 expression in mouse myoblasts. miR-144-5p affects myoblast senescence, myogenic differentiation, and autophagy by regulating the downstream target gene, Atg2A. Inhibiting miR-144-5p markedly increased the grip strength of the posterior limb in old mice, and the CSA of old mice and young mice was also markedly increased.

CONCLUSION

All experiments have demonstrated that miRNA-144-5p has a significant impact on the regulation of autophagy and the development of senile sarcopenia.

Allergen Microarrays and New Physical Approaches to More Sensitive and Specific Detection of Allergen-Specific Antibodies

The prevalence of allergic diseases has increased tremendously in recent decades, which can be attributed to growing exposure to environmental triggers, changes in dietary habits, comorbidity, and the increased use of medications. In this context, the multiplexed diagnosis of sensitization to various allergens and the monitoring of the effectiveness of treatments for allergic diseases become particularly urgent issues. The detection of allergen-specific antibodies, in particular, sIgE and sIgG, is a modern alternative to skin tests due to the safety and efficiency of this method. The use of allergen microarrays to detect tens to hundreds of allergen-specific antibodies in less than 0.1 mL of blood serum enables the transition to a deeply personalized approach in the diagnosis of these diseases while reducing the invasiveness and increasing the informativeness of analysis. This review discusses the technological approaches underlying the development of allergen microarrays and other protein microarrays, including the methods of selection of the microarray substrates and matrices for protein molecule immobilization, the obtainment of allergens, and the use of different types of optical labels for increasing the sensitivity and specificity of the detection of allergen-specific antibodies.

Upconversion Nanoparticle-Based Dot-Blot Immunoassay for Quantitative Biomarker Detection

Dot-blot immunoassays are widely used for the user-friendly detection of clinical biomarkers. However, the majority of dot-blot assays have only limited sensitivity and are only used for qualitative or semiquantitative analysis. To overcome this limitation, we have employed labels based on photon-upconversion nanoparticles (UCNPs) that exhibit anti-Stokes luminescence and can be detected without optical background interference. First, the dot-blot immunoassay on a nitrocellulose membrane was optimized for the quantitative analysis of human serum albumin (HSA), resulting in a limit of detection (LOD) of 0.19 ng/mL and a signal-to-background ratio (S/B) of 722. Commercial quantum dots were used as a reference label, reaching the LOD of 4.32 ng/mL and the S/B of 3, clearly indicating the advantages of UCNPs. In addition, the potential of UCNP-based dot-blot for real sample analysis was confirmed by analyzing spiked urine samples, reaching the LOD of 0.24 ng/mL and recovery rates from 79 to 123%. Furthermore, we demonstrated the versatility and robustness of the assay by adapting it to the detection of two other clinically relevant biomarkers, prostate-specific antigen (PSA) and cardiac troponin (cTn), reaching the LODs in spiked serum of 9.4 pg/mL and 0.62 ng/mL for PSA and cTn, respectively. Finally, clinical samples of patients examined for prostate cancer were analyzed, achieving a strong correlation with the reference electrochemiluminescence immunoassay (recovery rates from 89 to 117%). The achieved results demonstrate that UCNPs are highly sensitive labels that enable the development of dot-blot immunoassays for quantitative analysis of low-abundance biomarkers.

CDR grafting and site-directed mutagenesis approach for the generation and affinity maturation of Anti-CD20 nanobody

BACKGROUND

Recently, new and advanced techniques have been adopted to design and produce nanobodies, which are used in diagnostic and immunotherapy treatments. Traditionally, nanobodies are prepared from camelid immune libraries that require animal treatments. However, such approaches require large library sizes and complicated selection procedures. The current study has employed CDR grafting and site-directed mutagenesis techniques to create genetically engineered nanobodies against the tumor marker CD20 (anti-CD20 nanobodies) used in leukemia treatment.

METHODS AND RESULTS

In this study, we utilized the swapping method to graft CDRs from the VH Rituximab antibody to VHH CDRs. We aimed to enhance the binding affinity of the nanobodies by substituting the amino acids (Y101R-Y102R-Y107R) in the VHH-CDR3. To assess the binding capacity of the mutated nanobodies, we conducted an ELISA test. Moreover, through flow cytometry analysis, we compared the fluorescence intensity of the grafted CD20 and mutant nanobodies with that of the commercially available human anti-CD20 in Raji cells. The results showed a significant difference in the fluorescence intensity of the grafted nanobodies and mutant nanobodies when compared to the commercially available human anti-CD20.

CONCLUSION

The approach we followed in this study makes it possible to create multiple anti-CD20 nanobodies with varying affinities without the need for extensive selection efforts. Additionally, our research has demonstrated that computational tools are highly reliable in designing functional nanobodies.

The therapeutic effect of wine-processed Corni Fructus on chronic renal failure in rats through the interference with the LPS/IL-1-mediated inhibition of RXR function

ETHNOPHARMACOLOGICAL RELEVANCE

Corni Fructus, derived from the fruit of Cornus officinalis Sieb. et Zucc, is a widely utilized traditional Chinese medicine (TCM) with established efficacy in the treatment of diverse chronic kidney diseases. Crude Corni Fructus (CCF) and wine-processed Corni Fructus (WCF) are the main processed forms of Corni Fructus. Generally, TCM is often used after processing (paozhi). Despite the extensive use of processed TCM, the underlying mechanisms of processing for most TCMs have been unclear so far.

AIM OF THE STUDY

In this study, an integrated strategy combined renal metabolomics with proteomics was established and investigated the potential processing mechanisms of CCF or WCF on chronic renal failure (CRF) models.

MATERIALS AND METHODS

Firstly, the differences in biochemical parameters and pathological histology were compared to evaluate the effects of CCF and WCF on CRF model rats. Then, the tissue differential metabolites and proteins between CCF and WCF on CRF model rats were screened based on metabolomics and proteomics technology. Concurrently, a combined approach of metabolomics and proteomics was employed to investigate the underlying mechanisms associated with these marker metabolic products and proteins.

RESULTS

Compared to the MG group, there were 27 distinct metabolites and 143 different proteins observed in the CCF-treatment group, while the WCF-treatment group exhibited 24 distinct metabolites and 379 different proteins. Further, the integration interactions analysis of the protein and lipid metabolite revealed that both WCF and CCF improved tryptophan degradation and LPS/IL-1-mediated inhibition of RXR function. WCF inhibited RXR function more than CCF via the modulation of LPS/IL-1 in the CRF model. Experimental results were validated by qRT-PCR and western blotting. Notably, the gene expression amount and protein levels of FMO3 and CYP2E1 among 8 genes influenced by WCF were higher compared to CCF.

CONCLUSION

The results of this study provide a theoretical basis for further study of Corni Fructus with different processing techniques in CRF. The findings also offer guidance for investigating the mechanism of action of herbal medicines in diseases employing diverse processing techniques.

Lack of NAD(P)+ transhydrogenase activity in patients with primary adrenal insufficiency due to NNT variants

BACKGROUND

Pathogenic variants in the nicotinamide nucleotide transhydrogenase gene (NNT) are a rare cause of primary adrenal insufficiency (PAI), as well as functional impairment of the gonads.

OBJECTIVE

Despite the description of different homozygous and compound heterozygous NNT variants in PAI patients, the extent to which the function and expression of the mature protein are compromised remains to be clarified.

DESIGN

The activity and expression of mitochondrial NAD(P)+ transhydrogenase (NNT) were analyzed in blood samples obtained from patients diagnosed with PAI due to genetically confirmed variants of the NNT gene (n = 5), heterozygous carriers as their parents (n = 8), and healthy controls (n = 26).

METHODS

NNT activity was assessed by a reverse reaction assay standardized for digitonin-permeabilized peripheral blood mononuclear cells (PBMCs). The enzymatic assay was validated in PBMC samples from a mouse model of NNT absence. Additionally, the PBMC samples were evaluated for NNT expression by western blotting and reverse transcription quantitative polymerase chain reaction and for mitochondrial oxygen consumption.

RESULTS

NNT activity was undetectable (<4% of that of healthy controls) in PBMC samples from patients, independent of the pathogenic genetic variant. In patients' parents, NNT activity was approximately half that of the healthy controls. Mature NNT protein expression was lower in patients than in the control groups, while mRNA levels varied widely among genotypes. Moreover, pathogenic NNT variants did not impair mitochondrial bioenergetic function in PBMCs.

CONCLUSIONS

The manifestation of PAI in NNT-mutated patients is associated with a complete lack of NNT activity. Evaluation of NNT activity can be useful to characterize disease-causing NNT variants.

A Chromogenic Quantification of Protein Expression in Zebrafish Larvae

Western blot is a versatile and widely used technique in many areas of molecular biology and biotechnology for studying different protein characteristics. In general, the Western blot technique involves the extraction of proteins from the samples such as cells or tissues, which, after denaturation, are separated by molecular size using electrophoresis. The protein is then transferred to a membrane, typically PVDF or nitrocellulose, which, after blocking, is probed with specific antibodies labeled with a detection agent. Overall, this allows the recognition and binding to the target protein allowing the visualization of bands, a step called immunodetection. Over the years, new approaches to the Western blotting technique have been proposed to overcome performance limitations.This chapter describes a routine procedure for protein evaluation in zebrafish (Danio rerio) larvae, a widely used animal model for predicting the toxicity of drugs, by using a chromogenic substrate and allowing the proper execution of the technique without the costly equipment needed for detection.

Assessing Protein Expression in Patient-Derived Xenografts Using Western Blotting

The use of patient-derived xenografts (PDXs) in cancer research is increasing due to their ability to closely mimic the features of patient tumors. The ability to quickly and robustly measure protein expression levels in these tissues is a key methodology required in a broad range of experimental designs. Western blotting (WB) is a cost effective and simple tool that is highly specific and sensitive for detecting and quantifying individual proteins, posttranslational modifications and aberrant signaling pathways. Here, we described a method to assess protein expression in PDX tissues using WB to detect proteins involved in cell growth signaling pathways.

Goat Milk Improves Glucose Metabolism in Type 2 Diabetic Mice and Protects Pancreatic β-Cell Functions

SCOPE

Consuming goat milk is known to benefit high-fat diet-fed and streptozocin (STZ)-induced diabetic rats, but the underlying mechanisms are unknown. This study is conducted to investigate the metabolic effects of a goat milk diet (a form of goat milk powder) on glucose homeostasis and pancreatic conditions in a mouse model of Type 2 diabetes mellitus (T2DM) induced by STZ.

METHODS AND RESULTS

T2DM mice are fed with a goat-milk-based diet containing 10.3% w/w goat milk powder for 10 weeks for investigating the in vivo effects; a β-cell line MIN6 cells are used to test the in vitro effects of digested goat milk (DGM). Goat milk diet improves the deleterious effects of STZ on fasting glucose levels and glucose tolerance, accelerates pancreatic structure recovery, and alters blood metabolites in mice. Based on the significant differences observed in metabolites, the key pathways, metabolite regulatory enzymes, metabolite molecular modules, and biochemical reactions are identified as critical integrated pathways. DGM promotes the cell activity, glucose transportation, and AKT activation in cultured STZ-treated MIN6 cells in vitro.

CONCLUSIONS

Goat milk diet improves glucose homeostasis and pancreatic conditions of T2DM mice, in association with improved blood metabolite profiles and activation of pancreatic AKT pathway.

Flexible SERS Biosensor Based on Core-Shell Nanotags for Sensitive and Multiple Detection of T1DM Biomarkers

Sensitive and multiple detection of the biomarkers of type 1 diabetes mellitus (T1DM) is vital to the early diagnosis and clinical treatment of T1DM. Herein, we developed a SERS-based biosensor using polyvinylidene fluoride (PVDF) membranes as a flexible support for the detection of glutamic acid decarboxylase antibodies (GADA) and insulin autoantibodies (IAA). Two kinds of silver-gold core-shell nanotags embedded with Raman probes and attached with GADA or IAA antibodies were synthesized to capture the targets, enabling highly sensitive and highly selective detection of GADA and IAA. The embedded Raman probes sandwiched between silver and gold layers guaranteed spectral stability and reliability. Moreover, the utilization of two Raman probes enables simultaneous and multiplexing detection of both GADA and IAA, improving the detection accuracy for T1DM. The proposed SERS-based method has been proven feasible for clinical sample detection, demonstrating its great potential in sensitive, reliable, and rapid diagnosis of T1DM.

The development of microfluidic-based western blotting: Technical advances and future perspectives

Over the past two decades significant technical advancement in the field of western blotting has been made possible through the utilization of microfluidic technologies. In this review we provide a critical overview of these advancements, highlighting the advantages and disadvantages of each approach. Particular attention is paid to the development of now commercially available systems, including those for single cell analysis. This review also discusses more recent developments, including algorithms for automation and/or improved quantitation, the utilization of different materials/chemistries, use of projection electrophoresis, and the development of triBlots. Finally, the review includes commentary on future advances in the field based on current developments, and the potential of these systems for use as point-of-care devices in healthcare.

Ferric citrate-induced colonic mucosal damage associated with oxidative stress, inflammation responses, apoptosis, and the changes of gut microbial composition

Ferric citrate (FC) has been used as an iron fortifier and nutritional supplement, which is reported to induce colitis in rats, however the underlying mechanism remains to be elucidated. We performed a 16-week study of FC in male healthy C57BL/6 mice (nine-month-old) with oral administration of Ctr (0.9 % NaCl), 1.25 % FC (71 mg/kg/bw), 2.5 % FC (143 mg/kg/bw) and 5 % FC (286 mg/kg/bw). FC-exposure resulted in colon iron accumulation, histological alteration and reduce antioxidant enzyme activities, such as glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC), together with enhanced lipid peroxidation level, including malondialdehyde (MDA) level and 4-Hydroxynonenal (4-HNE) protein expression. Exposure to FC was associated with upregulated levels of the interleukin (IL)- 6, IL-1β, IL-18, IL-8 and tumor necrosis factor α (TNF-α), while down-regulated levels of IL-4 and IL-10. Exposure to FC was positively associated with the mRNA and protein expressions of cysteine-aspartic proteases (Caspase)- 9, Caspase-3, Bcl-2-associated X protein (Bax), while negatively associated with B-cell lymphoma 2 (Bcl2) in mitochondrial apoptosis signaling pathway. FC-exposure changed the diversity and composition of gut microbes. Additionally, the serum lipopolysaccharide (LPS) contents increased in FC-exposed groups when compared with the control group, while the expression of colonic tight junction proteins (TJPs), such as Claudin-1 and Occludin were decreased. These findings indicate that the colonic mucosal injury induced by FC-exposure are associated with oxidative stress generation, inflammation response and cell apoptosis, as well as the changes in gut microbes diversity and composition.

Methods of Sputum and Mucus Assessment for Muco-Obstructive Lung Diseases in 2022: Time to “Unplug” from Our Daily Routine!

Obstructive lung diseases, such as chronic obstructive pulmonary disease, asthma, or non-cystic fibrosis bronchiectasis, share some major pathophysiological features: small airway involvement, dysregulation of adaptive and innate pulmonary immune homeostasis, mucus hyperproduction, and/or hyperconcentration. Mucus regulation is particularly valuable from a therapeutic perspective given it contributes to airflow obstruction, symptom intensity, disease severity, and to some extent, disease prognosis in these diseases. It is therefore crucial to understand the mucus constitution of our patients, its behavior in a stable state and during exacerbation, and its regulatory mechanisms. These are all elements representing potential therapeutic targets, especially in the era of biologics. Here, we first briefly discuss the composition and characteristics of sputum. We focus on mucus and mucins, and then elaborate on the different sample collection procedures and how their quality is ensured. We then give an overview of the different direct analytical techniques available in both clinical routine and more experimental settings, giving their advantages and limitations. We also report on indirect mucus assessment procedures (questionnaires, high-resolution computed tomography scanning of the chest, lung function tests). Finally, we consider ways of integrating these techniques with current and future therapeutic options. Cystic fibrosis will not be discussed given its monogenic nature.

Mass Spectrometry versus Conventional Techniques of Protein Detection: Zika Virus NS3 Protease Activity towards Cellular Proteins

Mass spectrometry (MS) used in proteomic approaches is able to detect hundreds of proteins in a single assay. Although undeniable high analytical power of MS, data acquired sometimes lead to confusing results, especially during a search of very selective, unique interactions in complex biological matrices. Here, we would like to show an example of such confusing data, providing an extensive discussion on the observed phenomenon. Our investigations focus on the interaction between the Zika virus NS3 protease, which is essential for virus replication. This enzyme is known for helping to remodel the microenvironment of the infected cells. Several reports show that this protease can process cellular substrates and thereby modify cellular pathways that are important for the virus. Herein, we explored some of the targets of NS3, clearly shown by proteomic techniques, as processed during infection. Unfortunately, we could not confirm the biological relevance of protein targets for viral infections detected by MS. Thus, although mass spectrometry is highly sensitive and useful in many instances, also being able to show directions where cell/virus interaction occurs, we believe that deep recognition of their biological role is essential to receive complete insight into the investigated process.