Suborganellar resolution imaging for the localisation of human glycosylation enzymes in tobacco Golgi bodies.

Plant cells are a capable system for producing economically and therapeutically important proteins for a variety of applications, and are considered a safer production system than some existing hosts such as bacteria or yeasts. However, plants do not perform protein modifications in the same manner as mammalian cells do. This can impact on protein functionality for plant-produced human therapeutics. This obstacle can be overcome by creating a plant-based system capable of 'humanising' proteins of interest resulting in a glycosylation profile of synthetic plant-produced proteins as it would occur in mammalian systems. For this, the human glycosylation enzymes (HuGEs) involved in N-linked glycosylation N-acetylglucosaminyltransferase IV and V (GNTIV and GNTV), ß-1,4-galactosyltransferase (B4GALT1), and α-2,6-sialyltransferase (ST6GAL) were expressed in plant cells. For these enzymes to carry out the stepwise glycosylation functions, they need to localise to late Golgi body cisternae. This was achieved by a protein targeting strategy of replacing the mammalian Golgi targeting domains (Cytoplasmic-Transmembrane-Stem (CTS) regions) with plant-specific ones. Using high-resolution and dynamic confocal microscopy, we show that GNTIV and GNTV were successfully targeted to the medial-Golgi cisternae while ST6GAL and B4GALT1 were targeted to trans-Golgi cisternae. Plant cells are a promising system to produce human therapeutics for example proteins used in enzyme replacement therapies. Plants can provide safer and cheaper alternatives to existing expression systems such as mammalian cell culture, bacteria or yeast. An important factor for the functionality of therapeutic proteins though are protein modifications specific to human cells. However, plants do not perform protein modifications in the same manner as human cells do. Therefore, plant cells need to be genetically modified to mimic human protein modifications patterns. The modification of importance here, is called N-linked glycosylation and adds specific sugar molecules onto the proteins. Here we show the expression of four human glycosylation enzymes, which are required for N-linked glycosylation, in plant cells. In addition, as these protein modifications are carried out in cells resembling a factory production line, it is important that the human glycosylation enzymes be placed in the correct cellular compartments and in the correct order. This is carried out in Golgi bodies. Golgi bodies are composed of several defined stacks termed cis-, medial and trans-Golgi body stacks. For correct protein function, two of these human glycosylation enzymes need to be placed in the medial-Golgi attacks and the other two in the trans-Golgi stacks. Using high-resolution laser microscopy in live plant cells, we show here that the human glycosylation enzymes are sent within the cells to the correct Golgi body stacks. These are first steps to modify plant cells in order to produce human therapeutics.

High-Resolution Spatial Transcriptomic Atlas of Mouse Soleus Muscle: Unveiling Single Cell and Subcellular Heterogeneity in Health and Denervation.

Skeletal muscle is essential for both movement and metabolic processes, characterized by a complex and ordered structure. Despite its importance, a detailed spatial map of gene expression within muscle tissue has been challenging to achieve due to the limitations of existing technologies, which struggle to provide high-resolution views. In this study, we leverage the Seq-Scope technique, an innovative method that allows for the observation of the entire transcriptome at an unprecedented submicron spatial resolution. By applying this technique to the mouse soleus muscle, we analyze and compare the gene expression profiles in both healthy conditions and following denervation, a process that mimics aspects of muscle aging. Our approach reveals detailed characteristics of muscle fibers, other cell types present within the muscle, and specific subcellular structures such as the postsynaptic nuclei at neuromuscular junctions, hybrid muscle fibers, and areas of localized expression of genes responsive to muscle injury, along with their histological context. The findings of this research significantly enhance our understanding of the diversity within the muscle cell transcriptome and its variation in response to denervation, a key factor in the decline of muscle function with age. This breakthrough in spatial transcriptomics not only deepens our knowledge of muscle biology but also sets the stage for the development of new therapeutic strategies aimed at mitigating the effects of aging on muscle health, thereby offering a more comprehensive insight into the mechanisms of muscle maintenance and degeneration in the context of aging and disease.

Lectins as versatile tools to explore cellular glycosylation.

Lectins are naturally occurring carbohydrate-binding proteins that are ubiquitous in nature and highly selective for their, often incompletely characterised, binding partners. From their discovery in the late 1880s to the present day, they have provided a broad palette of versatile tools for exploring the glycosylation of cells and tissues and for uncovering the myriad functions of glycosylation in biological systems. The technique of lectin histochemistry, used to map the glycosylation of tissues, has been instrumental in revealing the changing profile of cellular glycosylation in development, health and disease. It has been especially enlightening in revealing fundamental alterations in cellular glycosylation that accompany cancer development and metastasis, and has facilitated the identification of glycosylated biomarkers that can predict prognosis and may have utility in development of early detection and screening, Moreover, it has led to insights into the functional role of glycosylation in healthy tissues and in the processes underlying disease. Recent advances in biotechnology mean that our understanding of the precise binding partners of lectins is improving and an ever-wider range of lectins are available, including recombinant human lectins and lectins with enhanced, engineered properties. Moreover, use of traditional histochemistry to support a broad range of cutting-edge technologies and the development of high throughout microarray platforms opens the way for ever more sophisticated mapping - and understanding - of the glycome.

Fiber-type traps: revisiting common misconceptions about skeletal muscle fiber types with application to motor control, biomechanics, physiology, and biology.

Skeletal muscle is a highly complex tissue that is studied by scientists from a wide spectrum of disciplines, including motor control, biomechanics, exercise science, physiology, cell biology, genetics, regenerative medicine, orthopedics, and engineering. Although this diversity in perspectives has led to many important discoveries, historically, there has been limited overlap in discussions across fields. This has led to misconceptions and oversimplifications about muscle biology that can create confusion and potentially slow scientific progress across fields. The purpose of this synthesis paper is to bring together research perspectives across multiple muscle fields to identify common assumptions related to muscle fiber type that are points of concern to clarify. These assumptions include 1) classification by myosin isoform and fiber oxidative capacity is equivalent, 2) fiber cross-sectional area (CSA) is a surrogate marker for myosin isoform or oxidative capacity, and 3) muscle force-generating capacity can be inferred from myosin isoform. We address these three fiber-type traps and provide some context for how these misunderstandings can and do impact experimental design, computational modeling, and interpretations of findings, from the perspective of a range of fields. We stress the dangers of generalizing findings about "muscle fiber types" among muscles or across species or sex, and we note the importance for precise use of common terminology across the muscle fields.

Maresin 1 repletion improves muscle regeneration after volumetric muscle loss.

The acute traumatic or surgical loss of skeletal muscle, known as volumetric muscle loss (VML), is a devastating type of injury that results in exacerbated and persistent inflammation followed by fibrosis. The mechanisms that mediate the magnitude and duration of the inflammatory response and ensuing fibrosis after VML remain understudied, and as such, the development of regenerative therapies has been limited. To address this need, we profiled how lipid mediators, which are potent regulators of the immune response after injury, varied with VML injuries that heal or result in fibrosis. We observed that non-healing VML injuries displayed increased pro-inflammatory eicosanoids and a lack of pro-resolving lipid mediators. Treatment of VML with a pro-resolving lipid mediator synthesized from docosahexaenoic acid, called Maresin 1, ameliorated fibrosis through reduction of neutrophils and macrophages and enhanced recovery of muscle strength. These results expand our knowledge of the dysregulated immune response that develops after VML and identify a novel immuno-regenerative therapeutic modality in Maresin 1.

Therapeutic Fractional Doses of Ionizing Radiation Promote Epithelial-Mesenchymal Transition, Enhanced Invasiveness, and Altered Glycosylation in MCF-7 Breast Cancer Cells.

The clinical outcome of radiation therapy is restricted due to the acquired radio-resistance of a subpopulation of tumour cells that may cause tumour relapse and distant metastasis. While the effects of ionizing radiation (IR) such as DNA damage and cell stress are well-documented, the potential role of IR in inducing invasive potential in cancer cells has not been broadly studied, therefore we aimed to investigate it in this study. MCF-7 cells irradiated with 0 Gy (control) or 2 Gy X-ray therapeutic doses of IR were assessed for cell viability, percentage of apoptotic cells, and reactive oxygen species (ROS) levels, DNA fragmentation, Matrigel invasion, assessment of epithelial-mesenchymal transition (EMT) markers and Helix pomatia agglutinin (HPA) binding at 30 min, 4- or 24-h post-IR. Reduction in cell viability, increase in apoptotic cells, ROS positive cells, and DNA fragmentation were observed, while functional invasiveness and EMT were exacerbated together with altered glycosylation in MCF-7 cells irradiated with 2 Gy X-ray compared to control cells. These findings indicate that despite the detrimental effects of 2 Gy X-ray IR on MCF-7 cells, a subpopulation of cells may have gained increased invasive potential. The exacerbated invasive potential may be attributed to enhanced EMT and altered glycosylation. Moreover, deregulation of transforming growth factor-beta (TGF-ß) following IR may be one of the elements responsible for these changes, as it lies in the intersection of these invasion-promoting cell processes.

Maintenance of subsynaptic myonuclei number is not driven by neural input.

The development and maintenance of neuromuscular junctions (NMJ) are supported by a specialized population of myonuclei that are referred to as the subsynaptic myonuclei (SSM). The relationship between the number of SSM and the integrity of the NMJ as well as the impact of a loss of innervation on SSM remain unclear. This study aimed to clarify these associations by simultaneously analyzing SSM counts and NMJ innervation status in three distinct mouse models of acute and chronic NMJ disruption. SSM were identified using fluorescent immunohistochemistry for Nesprin1 expression, which is highly enriched in SSM, along with anatomical location beneath the muscle fiber motor endplate. Acute denervation, induced by surgical nerve transection, did not affect SSM number after 7 days. Additionally, no significant changes in SSM number were observed during normal aging or in mice with chronic oxidative stress (Sod1 -/-). Both aging WT mice and Sod1 -/- mice accumulated degenerating and denervated NMJ in skeletal muscle, but there was no correlation between innervation status of a given NMJ and SSM number in aged or Sod1 -/- mice. These findings challenge the notion that a loss of SSM is a primary driver of NMJ degradation and leave open questions of the mechanisms that regulate SSM number as well as the physiological significance of the precise SSM number. Further investigations are required to define other properties of the SSM, such as transcriptional profiles and structural integrity, to better understand their role in NMJ maintenance.

Thrombospondin-1 promotes fibro-adipogenic stromal expansion and contractile dysfunction of the diaphragm in obesity.

Pulmonary disorders impact 40-80% of individuals with obesity. Respiratory muscle dysfunction is linked to these conditions; however, its pathophysiology remains largely undefined. Mice subjected to diet-induced obesity (DIO) develop diaphragmatic weakness. Increased intra-diaphragmatic adiposity and extracellular matrix (ECM) content correlate with reductions in contractile force. Thrombospondin-1 (THBS1) is an obesity-associated matricellular protein linked with muscular damage in genetic myopathies. THBS1 induces proliferation of fibro-adipogenic progenitors (FAPs)-mesenchymal cells that differentiate into adipocytes and fibroblasts. We hypothesized that THBS1 drives FAP-mediated diaphragm remodeling and contractile dysfunction in DIO. We tested this by comparing effects of dietary challenge on diaphragms of wild-type (WT) and Thbs1 knockout ( Thbs1 -/- ) mice. Bulk and single-cell transcriptomics demonstrated DIO-induced stromal expansion in WT diaphragms. Diaphragm FAPs displayed upregulation of ECM and TGFß-related expression signatures, and augmentation of a Thy1 -expressing sub-population previously linked to type 2 diabetes. Despite similar weight gain, Thbs1 -/- mice were protected from these transcriptomic changes, and from obesity-induced increases in diaphragm adiposity and ECM deposition. Unlike WT controls, Thbs1 -/- diaphragms maintained normal contractile force and motion after DIO challenge. These findings establish THBS1 as a necessary mediator of diaphragm stromal remodeling and contractile dysfunction in overnutrition, and potential therapeutic target in obesity-associated respiratory dysfunction.

Skeletal muscle structure, physiology, and function.

Contractions of skeletal muscles provide the stability and power for all body movements. Consequently, any impairment in skeletal muscle function results in some degree of instability or immobility. Factors that influence skeletal muscle structure and function are therefore of great interest scientifically and clinically. Injury, neuromuscular disease, and old age are among the factors that commonly contribute to impairments in skeletal muscle function. The goal of this chapter is to summarize the fundamentals of skeletal muscle structure and function to provide foundational knowledge for this Handbook volume. We examine the molecular interactions that provide the basis for the generation of force and movement, discuss mechanisms of the regulation of contraction at the level of myofibers, and introduce concepts of the activation and control of muscle function in vivo. Where appropriate, the chapter updates the emerging science that will increase understanding of muscle function.

Genotype-phenotype correlations in RHOBTB2-associated neurodevelopmental disorders.

PURPOSE: Missense variants clustering in the BTB domain region of RHOBTB2 cause a developmental and epileptic encephalopathy with early-onset seizures and severe intellectual disability. METHODS: By international collaboration, we assembled individuals with pathogenic RHOBTB2 variants and a variable spectrum of neurodevelopmental disorders. By western blotting, we investigated the consequences of missense variants in vitro. RESULTS: In accordance with previous observations, de novo heterozygous missense variants in the BTB domain region led to a severe developmental and epileptic encephalopathy in 16 individuals. Now, we also identified de novo missense variants in the GTPase domain in 6 individuals with apparently more variable neurodevelopmental phenotypes with or without epilepsy. In contrast to variants in the BTB domain region, variants in the GTPase domain do not impair proteasomal degradation of RHOBTB2 in vitro, indicating different functional consequences. Furthermore, we observed biallelic splice-site and truncating variants in 9 families with variable neurodevelopmental phenotypes, indicating that complete loss of RHOBTB2 is pathogenic as well. CONCLUSION: By identifying genotype-phenotype correlations regarding location and consequences of de novo missense variants in RHOBTB2 and by identifying biallelic truncating variants, we further delineate and expand the molecular and clinical spectrum of RHOBTB2-related phenotypes, including both autosomal dominant and recessive neurodevelopmental disorders.

Adjuvant chemotherapy following chemoradiotherapy as primary treatment for locally advanced cervical cancer versus chemoradiotherapy alone (OUTBACK): an international, open-label, randomised, phase 3 trial.

BACKGROUND: Standard treatment for locally advanced cervical cancer is chemoradiotherapy, but many patients relapse and die of metastatic disease. We aimed to determine the effects on survival of adjuvant chemotherapy after chemoradiotherapy. METHODS: The OUTBACK trial was a multicentre, open-label, randomised, phase 3 trial done in 157 hospitals in Australia, China, Canada, New Zealand, Saudi Arabia, Singapore, and the USA. Eligible participants were aged 18 year or older with histologically confirmed squamous cell carcinoma, adenosquamous cell carcinoma, or adenocarcinoma of the cervix (FIGO 2008 stage IB1 disease with nodal involvement, or stage IB2, II, IIIB, or IVA disease), Eastern Cooperative Oncology Group performance status 0-2, and adequate bone marrow and organ function. Participants were randomly assigned centrally (1:1) using a minimisation approach and stratified by pelvic or common iliac nodal involvement, requirement for extended-field radiotherapy, FIGO 2008 stage, age, and site to receive standard cisplatin-based chemoradiotherapy (40 mg/m2 cisplatin intravenously once-a-week for 5 weeks, during radiotherapy with 45·0-50·4 Gy external beam radiotherapy delivered in fractions of 1·8 Gy to the whole pelvis plus brachytherapy; chemoradiotherapy only group) or standard cisplatin-based chemoradiotherapy followed by adjuvant chemotherapy with four cycles of carboplatin (area under the receiver operator curve 5) and paclitaxel (155 mg/m2) given intravenously on day 1 of a 21 day cycle (adjuvant chemotherapy group). The primary endpoint was overall survival at 5 years, analysed in the intention-to-treat population (ie, all eligible patients who were randomly assigned). Safety was assessed in all patients in the chemoradiotherapy only group who started chemoradiotherapy and all patients in the adjuvant chemotherapy group who received at least one dose of adjuvant chemotherapy. The OUTBACK trial is registered with ClinicalTrials.gov, NCT01414608, and the Australia New Zealand Clinical Trial Registry, ACTRN12610000732088. FINDINGS: Between April 15, 2011, and June 26, 2017, 926 patients were enrolled and randomly assigned to the chemoradiotherapy only group (n=461) or the adjuvant chemotherapy group (n=465), of whom 919 were eligible (456 in the chemoradiotherapy only group and 463 in the adjuvant chemotherapy group; median age 46 years [IQR 37 to 55]; 663 [72%] were White, 121 [13%] were Black or African American, 53 [6%] were Asian, 24 [3%] were Aboriginal or Pacific islander, and 57 [6%] were other races) and included in the analysis. As of data cutoff (April 12, 2021), median follow-up was 60 months (IQR 45 to 65). 5-year overall survival was 72% (95% CI 67 to 76) in the adjuvant chemotherapy group (105 deaths) and 71% (66 to 75) in the chemoradiotherapy only group (116 deaths; difference 1% [95% CI -6 to 7]; hazard ratio 0·90 [95% CI 0·70 to 1·17]; p=0·81). In the safety population, the most common clinically significant grade 3-4 adverse events were decreased neutrophils (71 [20%] in the adjuvant chemotherapy group vs 34 [8%] in the chemoradiotherapy only group), and anaemia (66 [18%] vs 34 [8%]). Serious adverse events occurred in 107 (30%) in the adjuvant chemotherapy group versus 98 (22%) in the chemoradiotherapy only group, most commonly due to infectious complications. There were no treatment-related deaths. INTERPRETATION: Adjuvant carboplatin and paclitaxel chemotherapy given after standard cisplatin-based chemoradiotherapy for unselected locally advanced cervical cancer increased short-term toxicity and did not improve overall survival; therefore, it should not be given in this setting. FUNDING: National Health and Medical Research Council and National Cancer Institute.

Modulating fast skeletal muscle contraction protects skeletal muscle in animal models of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a lethal muscle disease caused by absence of the protein dystrophin, which acts as a structural link between the basal lamina and contractile machinery to stabilize muscle membranes in response to mechanical stress. In DMD, mechanical stress leads to exaggerated membrane injury and fiber breakdown, with fast fibers being the most susceptible to damage. A major contributor to this injury is muscle contraction, controlled by the motor protein myosin. However, how muscle contraction and fast muscle fiber damage contribute to the pathophysiology of DMD has not been well characterized. We explored the role of fast skeletal muscle contraction in DMD with a potentially novel, selective, orally active inhibitor of fast skeletal muscle myosin, EDG-5506. Surprisingly, even modest decreases of contraction (<15%) were sufficient to protect skeletal muscles in dystrophic mdx mice from stress injury. Longer-term treatment also decreased muscle fibrosis in key disease-implicated tissues. Importantly, therapeutic levels of myosin inhibition with EDG-5506 did not detrimentally affect strength or coordination. Finally, in dystrophic dogs, EDG-5506 reversibly reduced circulating muscle injury biomarkers and increased habitual activity. This unexpected biology may represent an important alternative treatment strategy for Duchenne and related myopathies.

Older mice show decreased regeneration of neuromuscular junctions following lengthening contraction-induced injury.

Progressive muscle atrophy and loss of muscle strength associated with old age have been well documented. Although age-associated impairments in skeletal muscle regeneration following injury have been demonstrated, less is known about whether aging impacts the regenerative response of neuromuscular junctions (NMJ) following contraction-induced injury. Reduced ability of NMJs to regenerate could lead to increased numbers of denervated muscle fibers and therefore play a contributing role to age-related sarcopenia. To investigate the relationship between age and NMJ regeneration following injury, extensor digitorum longus (EDL) muscles of middle-aged (18-19 months) and old mice (27-28 months) were subjected to a protocol of lengthening contractions (LC) that resulted in an acute force deficit of ~55% as well as functional and histological evidence of a similar magnitude of injury 3 days post LCs that was not different between age groups. After 28 days, the architecture and innervation of the NMJs were evaluated. The numbers of fragmented endplates increased and of fully innervated NMJs decreased post-injury for the muscle of both middle-aged and old mice and for contralateral uninjured muscles of old compared with uninjured muscles of middle-aged controls. Thus, the diminished ability of the skeletal muscle of old mice to recover following injury may be due in part to an age-related decrease in the ability to regenerate NMJs in injured muscles. The impaired ability to regenerate NMJs may be a triggering factor for degenerative changes at the NMJ contributing to muscle fiber weakness and loss in old age.

Lectin Histochemistry: Historical Perspectives, State of the Art, and Future Directions.

Lectins, discovered more than 100 years ago and defined by their ability to selectively recognize specific carbohydrate structures, are ubiquitous in living organisms. Their precise functions are as yet under-explored and incompletely understood but they are clearly involved, through recognition of their binding partners, in a myriad of biological mechanisms involved in cell identity, adhesion, signaling, and growth regulation in health and disease. Understanding the complex "sugar code" represented by the "glycome" is a major challenge and at the forefront of current biological research. Lectins have been widely employed in histochemical studies to map glycosylation in cells and tissues. Here, a brief history of the discovery of lectins and early developments in their use is presented along with a selection of some of the most interesting and significant discoveries to emerge from the use of lectin histochemistry. Further, an evaluation of the next generation of lectin-based technologies is presented, including the potential for designing recombinant lectins with more precisely defined binding characteristics, linking lectin-based studies with other technologies to answer fundamental questions in glycobiology and approaches to exploring the interactions of lectins with their binding partners in more detail.

Decoding muscle-resident Schwann cell dynamics during neuromuscular junction remodeling.

Understanding neuromuscular junction (NMJ) repair mechanisms is essential for addressing degenerative neuromuscular conditions. Here, we focus on the role of muscle-resident Schwann cells in NMJ reinnervation. In young Sod1-/- mice, a model of progressive NMJ degeneration, we identified a clear NMJ 'regenerative window' that allowed us to define regulators of reinnervation and crossing Sod1-/- mice with S100GFP-tg mice permitted visualization and analysis of Schwann cells. High-resolution imaging and single-cell RNA sequencing provide a detailed analysis of Schwann cell number, morphology, and transcriptome revealing multiple subtypes, including a previously unrecognized terminal Schwann cell (tSC) population expressing a synapse promoting signature. We also discovered a novel SPP1-driven cellular interaction between myelin Schwann cells and tSCs and show that it promotes tSC proliferation and reinnervation following nerve injury in wild type mice. Our findings offer important insights into molecular regulators critical in NMJ reinnervation that are mediated through tSCs to maintain NMJ function.

Neutrophil and natural killer cell imbalances prevent muscle stem cell-mediated regeneration following murine volumetric muscle loss.

Volumetric muscle loss (VML) overwhelms the innate regenerative capacity of mammalian skeletal muscle (SkM), leading to numerous disabilities and reduced quality of life. Immune cells are critical responders to muscle injury and guide tissue resident stem cell­ and progenitor-mediated myogenic repair. However, how immune cell infiltration and intercellular communication networks with muscle stem cells are altered following VML and drive pathological outcomes remains underexplored. Herein, we contrast the cellular and molecular mechanisms of VML injuries that result in the fibrotic degeneration or regeneration of SkM. Following degenerative VML injuries, we observed the heightened infiltration of natural killer (NK) cells as well as the persistence of neutrophils beyond 2 wk postinjury. Functional validation of NK cells revealed an antagonistic role in neutrophil accumulation in part via inducing apoptosis and CCR1-mediated chemotaxis. The persistent infiltration of neutrophils in degenerative VML injuries was found to contribute to impairments in muscle stem cell regenerative function, which was also attenuated by transforming growth factor beta 1 (TGFß1). Blocking TGFß signaling reduced neutrophil accumulation and fibrosis and improved muscle-specific force. Collectively, these results enhance our understanding of immune cell­stem cell cross talk that drives regenerative dysfunction and provide further insight into possible avenues for fibrotic therapy exploration.

GALNTs: master regulators of metastasis-associated epithelial-mesenchymal transition (EMT)?

In humans, the UDP-N-α-D galactosamine:polypeptide N-acetylgalactosaminyltransferases family (ppGalNAc-Ts, GalNAc-Ts or GALNTs) comprises 20 isoenzymes. They are responsible for the initial synthesis of α-GalNAc1,3-O-Ser/Thr, or Tn antigen, at initiation of mucin type O-linked glycosylation. This structure is normally extended by the further sequential action of glycosytransferases to build more complex linear or branched O-linked structures, but in cancers it is frequently left unelaborated, and its presence is often associated with poor patient prognosis. Altered levels of GALNT expression or distribution have also been extensively reported in a wide range of cancers. These changes would be predicted to result in marked alterations in GalNAc O-linked glycosylation, including altered levels of site specific O-linked glycosylation and changes in the glycan structures formed, including, potentially, exposure of truncated O-glycans such as Tn antigen. Many reports have demonstrated that altered levels of specific GALNTs have prognostic significance in cancers, or shown that they are associated with changes in cell behaviour, including proliferation, migration, invasion or growth and metastasis in animal models. We have previously reviewed how deregulation of GALNTs in several epithelial cancers is a feature of different stages metastasis. Here we consider evidence that changes in GALNT expression, and therefore consequent alterations in GalNAc O-linked glycosylation, may directly influence molecules implicated in aspects of epithelial-mesenchymal transition (EMT), a fundamental aspect of cancer metastasis, during which epithelial cancer cells lose their cell-cell junctions, apical-basal polarity and adhesive interactions with basement membrane and become mesenchymal, with a spindle-shaped morphology and increased migratory capacity.

Scavenging mitochondrial hydrogen peroxide by peroxiredoxin 3 overexpression attenuates contractile dysfunction and muscle atrophy in a murine model of accelerated sarcopenia.

Age-related muscle atrophy and weakness, or sarcopenia, are significant contributors to compromised health and quality of life in the elderly. While the mechanisms driving this pathology are not fully defined, reactive oxygen species, neuromuscular junction (NMJ) disruption, and loss of innervation are important risk factors. The goal of this study is to determine the impact of mitochondrial hydrogen peroxide on neurogenic atrophy and contractile dysfunction. Mice with muscle-specific overexpression of the mitochondrial H2 O2  scavenger peroxiredoxin3 (mPRDX3) were crossed to Sod1KO mice, an established mouse model of sarcopenia, to determine whether reduced mitochondrial H2 O2 can prevent or delay the redox-dependent sarcopenia. Basal rates of H2 O2  generation were elevated in isolated muscle mitochondria from Sod1KO, but normalized by mPRDX3 overexpression. The mPRDX3 overexpression prevented the declines in maximum mitochondrial oxygen consumption rate and calcium retention capacity in Sod1KO. Muscle atrophy in Sod1KO was mitigated by ~20% by mPRDX3 overexpression, which was associated with an increase in myofiber cross-sectional area. With direct muscle stimulation, maximum isometric specific force was reduced by ~20% in Sod1KO mice, and mPRDX3 overexpression preserved specific force at wild-type levels. The force deficit with nerve stimulation was exacerbated in Sod1KO compared to direct muscle stimulation, suggesting NMJ disruption in Sod1KO. Notably, this defect was not resolved by overexpression of mPRDX3. Our findings demonstrate that muscle-specific PRDX3 overexpression reduces mitochondrial H2 O2  generation, improves mitochondrial function, and mitigates loss of muscle quantity and quality, despite persisting NMJ impairment in a murine model of redox-dependent sarcopenia.

Utilising extracellular vesicles for early cancer diagnostics: benefits, challenges and recommendations for the future.

To increase cancer patient survival and wellbeing, diagnostic assays need to be able to detect cases earlier, be applied more frequently, and preferably before symptoms develop. The expansion of blood biopsy technologies such as detection of circulating tumour cells and cell-free DNA has shown clinical promise for this. Extracellular vesicles released into the blood from tumour cells may offer a snapshot of the whole of the tumour. They represent a stable and multifaceted complex of a number of different types of molecules including DNA, RNA and protein. These represent biomarker targets that can be collected and analysed from blood samples, offering great potential for early diagnosis. In this review we discuss the benefits and challenges of the use of extracellular vesicles in this context and provide recommendations on where this developing field should focus their efforts to bring future success.