Background. Hypertension (HPT) and its complications continue to pose a global threat and contribute to premature mortality worldwide. The adverse interactions between HPT, obesity and COVID-19 are ...currently being witnessed globally and represent a collision of pandemics. Understanding the burden that this non-communicable disease (NCD) poses in KwaZulu-Natal (KZN) Province, South Africa (SA), would help in developing improved public healthcare strategies. Objectives. To describe the burden of HPT in all the districts of KZN over a 6-year period. Methods. HPT data are routinely collected from all KZN public health facilities (both clinics and hospitals) as part of the District Health Information System (DHIS). In this retrospective study, we accessed HPT records from the DHIS over a period of 6 years (2014 - 2019, inclusive). Data collected included the number of patients screened, diagnosed and initiated on therapy for HPT, together with the number of obese patients. Results. The slopes for HPT screening were positive at both clinics and hospitals in KZN (considerably more at clinics than hospitals, with a difference in elevations of slopes of p<0.001), with a significantly greater percentage of the population having been screened at rural clinics than at hospitals (difference in elevation of slopes p<0.001). A significantly greater number of patients aged <40 years (p<0.001) were being screened for HPT at clinics than at hospitals (2017/18, 2018/19, 2019/20), while hospitals screened considerably more patients aged ≥40 years in 2017 - 2018 (p<0.001). The numbers of new hypertensives diagnosed and having treatment initiated were on an upward slope at both clinics and hospitals, with clinics having a greater elevation of slope than hospitals (p<0.001), irrespective of patient age. A significantly greater number of patients aged ≥40 years (p<0.05) were diagnosed with HPT at both clinics and hospitals in KZN (2017/18, 2018/19, 2019/20). KZN clinics remained the first port of call for known hypertensives throughout the study period. Obesity was prevalent at both clinic and hospital level, although figures were significantly higher at clinics. Over 80% of the obesity burden was carried by the rural clinics and hospitals. Conclusions. Screening, diagnosis, treatment initiation and chronic management of HPT occur mainly at rural clinic level. The SA government needs to heed these findings and redirect resources (staffing and equipment) to this level. The prevalence of obesity was highest at rural healthcare facilities (clinics more than hospitals). More needs to be done to combat the obesity pandemic if we are to win the battle against NCDs (HPT and diabetes mellitus). A significant number of patients aged <40 years are being screened for HPT, which bodes well for the province, as early diagnosis and treatment of HPT are vital to prevent complications.
Adeno-associated virus (AAV) vectors are currently the leading candidates for virus-based gene therapies because of their broad tissue tropism, non-pathogenic nature and low immunogenicity. They have ...been successfully used in clinical trials to treat hereditary diseases such as haemophilia B (ref. 2), and have been approved for treatment of lipoprotein lipase deficiency in Europe. Considerable efforts have been made to engineer AAV variants with novel and biomedically valuable cell tropisms to allow efficacious systemic administration, yet basic aspects of AAV cellular entry are still poorly understood. In particular, the protein receptor(s) required for AAV entry after cell attachment remains unknown. Here we use an unbiased genetic screen to identify proteins essential for AAV serotype 2 (AAV2) infection in a haploid human cell line. The most significantly enriched gene of the screen encodes a previously uncharacterized type I transmembrane protein, KIAA0319L (denoted hereafter as AAV receptor (AAVR)). We characterize AAVR as a protein capable of rapid endocytosis from the plasma membrane and trafficking to the trans-Golgi network. We show that AAVR directly binds to AAV2 particles, and that anti-AAVR antibodies efficiently block AAV2 infection. Moreover, genetic ablation of AAVR renders a wide range of mammalian cell types highly resistant to AAV2 infection. Notably, AAVR serves as a critical host factor for all tested AAV serotypes. The importance of AAVR for in vivo gene delivery is further highlighted by the robust resistance of Aavr(-/-) (also known as Au040320(-/-) and Kiaa0319l(-/-)) mice to AAV infection. Collectively, our data indicate that AAVR is a universal receptor involved in AAV infection.
The renin-angiotensin system is mainly associated with the regulation of blood pressure, but recently many other functions of this system have been described. ACE2, an 805-amino acid ...monocarboxypeptidase type I transmembrane glycoprotein, was discovered in 2000 and has sequence similarity to two other proteins, namely ACE and collectrin. The ACE2 gene is located on Xp22 and is highly polymorphic. ACE2 is expressed in numerous tissues especially the lung alveolar epithelial cells, heart, kidney and gastrointestinal tract. Animal studies have found that ACE2 is central in diseases affecting almost all organ systems, among other cardiac, respiratory, renal and endocrine functions. ACE2 was identified as the cellular contact point for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the global pandemic (COVID-19), and is a potential drug target. SARS-CoV-2 infection has several effects on the renin-angiotensin system and conversely, regulation of this receptor may affect the progress of infection. We describe the genetics and functions of ACE2, explore its various physiological functions in the renin-angiotensin system and discuss its role in the pathophysiology of disease. ACE2 opposes the vasopressor ACE pathway of the renin-angiotensin system by converting angiotensin (Ang) I to Ang (1-9) and Ang II to Ang (1-7) which initiates the vasodilatory pathway. ACE2 may have a protective effect in the lung and kidney as knockout mice display susceptibility to acute respiratory distress and hypertensive nephropathy. Binding of SARS-CoV-2 and the subsequent fusion and downregulation of this pathway during SARS-CoV-2 infection may explain some of the unusual sequelae seen in COVID-19.
Antibodies have proven to be central in the development of diagnostic methods over decades, moving from polyclonal antibodies to the milestone development of monoclonal antibodies. Although ...monoclonal antibodies play a valuable role in diagnosis, their production is technically demanding and can be expensive. The large size of monoclonal antibodies (150 kDa) makes their re-engineering using recombinant methods a challenge. Single-domain antibodies, such as “nanobodies,” are a relatively new class of diagnostic probes that originated serendipitously during the assay of camel serum. The immune system of the camelid family (camels, llamas, and alpacas) has evolved uniquely to produce heavy-chain antibodies that contain a single monomeric variable antibody domain in a smaller functional unit of 12–15 kDa. Interestingly, the same biological phenomenon is observed in sharks. Since a single-domain antibody molecule is smaller than a conventional mammalian antibody, recombinant engineering and protein expression
in vitro
using bacterial production systems are much simpler. The entire gene encoding such an antibody can be cloned and expressed
in vitro
. Single-domain antibodies are very stable and heat-resistant, and hence do not require cold storage, especially when incorporated into a diagnostic kit. Their simple genetic structure allows easy re-engineering of the protein to introduce new antigen-binding characteristics or attach labels. Here, we review the applications of single-domain antibodies in laboratory diagnosis and discuss the future potential in this area.
Background Ideal control of diabetes mellitus (DM) remains a global goal, which has not yet been reached. As part of an integrated public healthcare strategy, data with subsequent analysis of ...diabetes control achieved in patients living with DM (PLWD) need to be available. Diabetes control data from KwaZulu-Natal (KZN) Province, South Africa, are scarce. Smaller studies conducted in public and private healthcare sectors of KZN have shown suboptimal DM control.Objectives To identify the percentage of glycated haemoglobin (HbA1c) tests done in KZN public healthcare facilities, and to provide a glimpse into diabetes control being achieved in each KZN district municipality.Methods Data regarding the number of HbA1c tests performed, number of patients with an HbA1c ≤7% and number of diabetes visits were accessed from the KZN Department of Health Information Systems and analysed.Results The majority of HbA1c tests were performed in the metro municipality of eThekwini (p7%. Most of the patients in 9 of the 11 district municipalities showed suboptimal control of their DM. The total number of HbA1c tests performed in KZN represents approximately one-tenth of the total number of diabetes treatment visits. This trend was prevalent in all 11 district municipalities, where the incidence of DM was on an upward trajectory.Conclusions Our study demonstrated that the majority of PLWD visiting public healthcare facilities in KZN have suboptimal glycaemic control. They are at increased risk of developing diabetes-related complications, further burdening the healthcare fiscus of low- to middle- income countries. We also showed that the number of HbA1c tests being performed, in the presence of suboptimal control, was well below par. This finding serves to emphasise the need for strategies to be implemented to increase awareness of HbA1c testing for the monitoring of glycaemic control, and for making point-of-care HbA1c testing readily available in these healthcare facilities.
The year 2020 has seen a major and sustained outbreak of a novel betacoronavirus (severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2) infection that causes fever, severe respiratory illness ...and pneumonia, a disease called COVID-19. At the time of writing, the death toll was greater than 120 000 worldwide with more than 2 million documented infections. The genome of the CoV encodes a number of structural proteins that facilitate cellular entry and assembly of virions, of which the spike protein S appears to be critical for cellular entry. The spike protein guides the virus to attach to the host cell. The spike protein contains a receptor-binding domain (RBD), a fusion domain and a transmembrane domain. The RBD of spike protein S binds to Angiotensin Converting Enzyme 2 (ACE2) to initiate cellular entry. The spike protein of SARS-CoV-2 shows more than 90% amino acid similarity to the pangolin and bat CoVs and these also use ACE2 as a receptor. Binding of the spike protein to ACE2 exposes the cleavage sites to cellular proteases. Cleavage of the spike protein by transmembrane protease serine 2 and other cellular proteases initiates fusion and endocytosis. The spike protein contains an addition furin cleavage site that may allow it to be 'preactivated' and highly infectious after replication. The fundamental role of the spike protein in infectivity suggests that it is an important target for vaccine development, blocking therapy with antibodies and diagnostic antigen-based tests. This review briefly outlines the structure and function of the 2019 novel CoV/SARS-CoV-2 spike protein S.
Synthetic biology has emerged from molecular biology and engineering approaches and aims to develop novel, biologically-inspired systems for industrial and basic research applications ranging from ...biocomputing to drug production. Surprisingly, redoxin (thioredoxin, glutaredoxin, peroxiredoxin) and other thiol-based redox systems have not been widely utilized in many of these synthetic biology applications.
We reviewed thiol-based redox systems and the development of synthetic biology applications that have used thiol-dependent parts.
The development of circuits to facilitate cytoplasmic disulfide bonding, biocomputing and the treatment of intestinal bowel disease are amongst the applications that have used thiol-based parts. We propose that genetically encoded redox sensors, thiol-based biomaterials and intracellular hydrogen peroxide generators may also be valuable components for synthetic biology applications.
Thiol-based systems play multiple roles in cellular redox metabolism, antioxidant defense and signaling and could therefore offer a vast and diverse portfolio of components, parts and devices for synthetic biology applications. However, factors limiting the adoption of redoxin systems for synthetic biology applications include the orthogonality of thiol-based components, limitations in the methods to characterize thiol-based systems and an incomplete understanding of the design principles of these systems.
Thioredoxin, glutaredoxin and peroxiredoxin systems play central roles in redox regulation, signaling and metabolism in cells. In these systems, reducing equivalents from NAD(P)H are transferred by ...coupled thiol-disulfide exchange reactions to redoxins which then reduce a wide array of targets. However, the characterization of redoxin activity has been unclear, with redoxins regarded as enzymes in some studies and redox metabolites in others. Consequently, redoxin activities have been quantified by enzyme kinetic parameters in vitro, and redox potentials or redox ratios within cells. By analyzing all the reactions within these systems, computational models showed that many kinetic properties attributed to redoxins were due to system-level effects. Models of cellular redoxin networks have also been used to estimate intracellular hydrogen peroxide levels, analyze redox signaling and couple omic and kinetic data to understand the regulation of these networks in disease. Computational modeling has emerged as a powerful complementary tool to traditional redoxin enzyme kinetic and cellular assays that integrates data from a number of sources into a single quantitative framework to accelerate the analysis of redoxin systems.
A critical feature of the cellular antioxidant response is the induction of gene expression by redox-sensitive transcription factors. In many cells, activating these transcription factors is a ...dynamic process involving multiple redox steps, but it is unclear how these dynamics should be measured. Here, we show how the dynamic profile of the Schizosaccharomyces pombe Pap1 transcription factor is quantifiable by three parameters: signal amplitude, signal time and signal duration. In response to increasing hydrogen peroxide concentrations, the Pap1 amplitude decreased while the signal time and duration showed saturable increases. In co-response plots, these parameters showed a complex, non-linear relationship to the mRNA levels of four Pap1-regulated genes. We also demonstrate that hydrogen peroxide and tert-butyl hydroperoxide trigger quantifiably distinct Pap1 activation profiles and transcriptional responses. Based on these findings, we propose that different oxidants and oxidant concentrations modulate the Pap1 dynamic profile, leading to specific transcriptional responses. We further show how the effect of combination and pre-exposure stresses on Pap1 activation dynamics can be quantified using this approach. This method is therefore a valuable addition to the redox signalling toolbox that may illuminate the role of dynamics in determining appropriate responses to oxidative stress.
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•Redox transcription factors (TF) play critical roles in the antioxidant response.•It is unclear how to measure redox TF signals from dynamic activation profiles.•Fission yeast Pap1 profiles were quantified by signal amplitude, time and duration.•Pap1 dynamics facilitate a graded response to different oxidative inputs.•Redox signal dynamics may an important feature of redox regulation.
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