MiR-150 and miR-155 expression predicts survival of cervical cancer patients: a translational approach to novel prognostic biomarkers.

INTRODUCTION: High-risk human papillomavirus (HPV) is the aetiological agent of cervical cancer, which remains the fourth leading cause of cancer death in women worldwide. K14-HPV16 transgenic mice are a model for HPV-induced cancers, which undergo multistep squamous carcinogenesis at the skin, that is histologically and molecularly similar to carcinogenesis of the human cervix. Previous screens of differentially regulated microRNAs (miRs) using K14-HPV16 mice showed a role for miR-21, miR-155, miR-150, miR-146a, miR-125b and miR-223 during carcinogenesis. METHODS: We now aim to translate these observations into the clinical setting, using data provided by The Cancer Genome Atlas (TCGA) to explore whether those microRNAs can influence the survival of cervical cancer patients. RESULTS: Results showed that low miR-150, miR-155 and miR-146a expression levels in primary tumours were associated with poor overall survival. However, only miR-150 and miR-155 were found to be independent predictors, increasing the risk of death. When patients were stratified by clinical stage, low miR-150, miR-155, miR-146a and miR-125b were associated with poor survival for clinical stages I and II. Only low miR-150 expression increased the death risk. CONCLUSION: We conclude that miR-150 and miR-155 may be potentially applied as prognostic biomarkers in cervical cancer patients. However, further investigation is required to determine their applicability.

Recommendations of good practice to prevent aspiration pneumonia in older adults at risk of oropharyngeal dysphagia living in nursing homes: A modified e-Delphi study protocol.

BACKGROUND: Aspiration pneumonia (AP) is a subset of pneumonia caused by the aspiration of food and fluids to the lungs and is highly prevalent in the older population. Oropharyngeal dysphagia (OD) is one of the risk factors for AP and it is also associated with malnutrition, dehydration and poor functional outcomes. As pneumonia is the second most common infection in nursing homes (NHs) and OD represents a major concern to NH staff, good practices for the prevention of AP in older adults at risk of OD are needed. PURPOSE: The aim of this modified e-Delphi study is to build consensus among a panel of experts regarding a set of recommendations for NH staff on good practices to prevent AP in older adults at risk of OD living in NHs. The objective of this paper is to establish the methodology inherent to the Delphi study. METHODS: An online modified Delphi study will be developed in three rounds. Criteria for the Delphi panel participants include holding a master's or doctoral degree in OD or speech and language therapy; or having 10 or more years of experience in OD; or having at least one scientific publication related to OD. A previously described modified Delphi methodology will be used to achieve consensus (75% agreement). An additional round will be performed to collect the experts' perspectives regarding the priority for application of each recommendation previously validated. DISCUSSION: This protocol aimed to describe the methodology of a future Delphi study on the prevention of AP, seeking to fulfil the gap in the literature regarding this topic. The modified Delphi technique is a widely used method for collecting experts' opinion in health sciences, but the absence of standardised guidelines allows some heterogeneity between studies with the same aim. WHAT THIS PAPER ADDS: What is already known on the subject Aspiration pneumonia (AP) is related to three main risk factors: impaired safety of swallow, impaired nutritional status and poor oral health. It is known that being dependent for feeding is one of the main risk factors for AP and around 50% of nursing home (NH) residents need feeding assistance. Thus, it is important to promote specialised intervention and care by the NH staff for preventing AP. What this paper adds to existing knowledge It is hypothesised that increasing the knowledge of NH staff regarding the best practices for preventing AP in older adults at risk of oropharyngeal dysphagia (OD) will improve outcomes such as quality of life, incidence of AP and mortality. What are the potential or actual clinical implications of this work? The recommendations resulting from this study will address a current gap in healthcare practice of NH staff regarding older adults at increased risk for OD and, consequently, for AP.

The PfAP2-G2 transcription factor is a critical regulator of gametocyte maturation.

Differentiation from asexual blood stages to mature sexual gametocytes is required for the transmission of malaria parasites. Here, we report that the ApiAP2 transcription factor, PfAP2-G2 (PF3D7_1408200) plays a critical role in the maturation of Plasmodium falciparum gametocytes. PfAP2-G2 binds to the promoters of a wide array of genes that are expressed at many stages of the parasite life cycle. Interestingly, we also find binding of PfAP2-G2 within the gene body of almost 3,000 genes, which strongly correlates with the location of H3K36me3 and several other histone modifications as well as Heterochromatin Protein 1 (HP1), suggesting that occupancy of PfAP2-G2 in gene bodies may serve as an alternative regulatory mechanism. Disruption of pfap2-g2 does not impact asexual development, but the majority of sexual parasites are unable to mature beyond stage III gametocytes. The absence of pfap2-g2 leads to overexpression of 28% of the genes bound by PfAP2-G2 and none of the PfAP2-G2 bound genes are downregulated, suggesting that it is a repressor. We also find that PfAP2-G2 interacts with chromatin remodeling proteins, a microrchidia (MORC) protein, and another ApiAP2 protein (PF3D7_1139300). Overall our data demonstrate that PfAP2-G2 establishes an essential gametocyte maturation program in association with other chromatin-related proteins.

Developmental regulation of DNA cytosine methylation at the immunoglobulin heavy chain constant locus.

DNA cytosine methylation is involved in the regulation of gene expression during development and its deregulation is often associated with disease. Mammalian genomes are predominantly methylated at CpG dinucleotides. Unmethylated CpGs are often associated with active regulatory sequences while methylated CpGs are often linked to transcriptional silencing. Previous studies on CpG methylation led to the notion that transcription initiation is more sensitive to CpG methylation than transcriptional elongation. The immunoglobulin heavy chain (IgH) constant locus comprises multiple inducible constant genes and is expressed exclusively in B lymphocytes. The developmental B cell stage at which methylation patterns of the IgH constant genes are established, and the role of CpG methylation in their expression, are unknown. Here, we find that methylation patterns at most cis-acting elements of the IgH constant genes are established and maintained independently of B cell activation or promoter activity. Moreover, one of the promoters, but not the enhancers, is hypomethylated in sperm and early embryonic cells, and is targeted by different demethylation pathways, including AID, UNG, and ATM pathways. Combined, the data suggest that, rather than being prominently involved in the regulation of the IgH constant locus expression, DNA methylation may primarily contribute to its epigenetic pre-marking.

Two modes of cis-activation of switch transcription by the IgH superenhancer.

B cell isotype switching plays an important role in modulating adaptive immune responses. It occurs in response to specific signals that often induce different isotype (I) promoters driving transcription of switch regions, located upstream of the Ig heavy chain (IgH) constant genes. The transcribed switch regions can recombine, leading to a change of the constant gene and, consequently, of antibody isotype. Switch transcription is controlled by the superenhancer 3' regulatory region (3'RR) that establishes long-range chromatin cis-interactions with I promoters. Most stimuli induce more than one I promoter, and switch transcription can occur on both chromosomes. Therefore, it is presently unknown whether induced I promoters compete for the 3'RR on the same chromosome. Here we performed single-chromosome RT-qPCR assays to examine switch transcription monoallelically in the endogenous context. We show that there are two modes of 3'RR-mediated activation of I promoters: coactivation and competition. The nature of the inducing signal plays a pivotal role in determining the mode of activation. Furthermore, we provide evidence that, in its endogenous setting, the 3'RR has a bidirectional activity. We propose that the coactivation and competition modes mediated by the 3'RR may have evolved to cope with the different kinetics of primary immune responses.

Human Papillomavirus 16-Transgenic Mice as a Model to Study Cancer-Associated Cachexia.

Cancer cachexia is a multifactorial syndrome characterized by general inflammation, weight loss and muscle wasting, partly mediated by ubiquitin ligases such as atrogin-1, encoded by Fbxo32. Cancers induced by high-risk human papillomavirus (HPV) include anogenital cancers and some head-and-neck cancers and are often associated with cachexia. The aim of this study was to assess the presence of cancer cachexia in HPV16-transgenic mice with or without exposure to the chemical carcinogen 7,12-dimethylbenz(a)anthracene (DMBA). Male mice expressing the HPV16 early region under the control of the cytokeratin 14 gene promoter (K14-HPV16; HPV+) and matched wild-type mice (HPV-) received DMBA (or vehicle) topically over 17 weeks of the experiment. Food intake and body weight were assessed weekly. The gastrocnemius weights and Fbxo32 expression levels were quantified at sacrifice time. HPV-16-associated lesions in different anatomic regions were classified histologically. Although unexposed HPV+ mice showed higher food intake than wild-type matched group (p < 0.01), they presented lower body weights (p < 0.05). This body weight trend was more pronounced when comparing DMBA-exposed groups (p < 0.01). The same pattern was observed in the gastrocnemius weights (between the unexposed groups: p < 0.05; between the exposed groups: p < 0.001). Importantly, DMBA reduced body and gastrocnemius weights (p < 0.01) when comparing the HPV+ groups. Moreover, the Fbxo32 gene was overexpressed in DMBA-exposed HPV+ compared to control mice (p < 0.05). These results show that K14-HPV16 mice closely reproduce the anatomic and molecular changes associated with cancer cachexia and may be a good model for preclinical studies concerning the pathogenesis of this syndrome.

Dimethylaminoparthenolide reduces the incidence of dysplasia and ameliorates a wasting syndrome in HPV16-transgenic mice.

The nuclear factor kappa light chain enhancer of activated B cells (NF-κB) has been implicated in the progression of cancers induced by high-risk human papillomaviruses (HPV). In cancer patients, NF-κB is also thought to drive a chronic systemic inflammatory status, leading to cachexia. This study addressed the ability of dimethylaminoparthenolide (DMAPT), a water-soluble NF-κB inhibitor, to block the development of HPV-induced lesions and wasting syndrome in HPV16-transgenic mice. Mice received DMAPT orally (100 mg/kg/day), once a day, for 6 consecutive weeks. Body weight was monitored weekly along with food and water intake. After 6 weeks the animals were submitted to a grip strength test and sacrificed for specimen collection. Skin samples were analyzed histologically and for expression of NF-κB-regulated genes Bcl2 and Bcl2l1. Gastrocnemius muscles were weighted and analyzed for expression of NF-κB subunits p50, p52, p65, and Rel-B. DMAPT reduced the incidence of epidermal dysplasia (18.2% versus 33.3% in HPV16+/- untreated mice). This was associated with reduced expression of Bcl2 and Bcl2l1 (p = .0003 and p = .0014, respectively) and reduced neutrophilic infiltration (p = .0339). Treated mice also showed partially preserved bodyweight and strength, which were independent of the expression levels of NF-κB subunits in skeletal muscle.These results suggest that NF-κB inhibition may be a valid strategy against HPV-induced lesions in vivo and warrant further preclinical tests particularly in the set of combination therapies. In addition, the data may support the use of DMAPT to prevent wasting syndrome.

Dissection of minimal sequence requirements for rhoptry membrane targeting in the malaria parasite.

Rhoptries are specialized secretory organelles characteristic of single cell organisms belonging to the clade Apicomplexa. These organelles play a key role in the invasion process of host cells by accumulating and subsequently secreting an unknown number of proteins mediating host cell entry. Despite their essential role, little is known about their biogenesis, components and targeting determinants. Here, we report on a conserved apicomplexan protein termed Armadillo Repeats-Only (ARO) protein that we localized to the cytosolic face of Plasmodium falciparum and Toxoplasma gondii rhoptries. We show that the first 20 N-terminal amino acids are sufficient for rhoptry membrane targeting. This protein relies on both - myristoylation and palmitoylation motifs - for membrane attachment. Although these lipid modifications are essential, they are not sufficient to direct ARO to the rhoptry membranes. Mutational analysis revealed additional residues within the first 20 amino acids of ARO that play an important role for rhoptry membrane attachment: the positively charged residues R9 and K14. Interestingly, the exchange of R9 with a negative charge entirely abolishes membrane attachment, whereas the exchange of K14 (and to a lesser extent K16) alters only its membrane specificity. Additionally, 17 proteins predicted to be myristoylated and palmitoylated in the first 20 N-terminal amino acids were identified in the genome of the malaria parasite. While most of the corresponding GFP fusion proteins were trafficked to the parasite plasma membrane, two were sorted to the apical organelles. Interestingly, these proteins have a similar motif identified for ARO.

Adipose tissue rearrangement in cancer cachexia: The involvement of ß3-adrenergic receptor associated pathways.

Cancer-associated cachexia (CAC) is a complex multiple organ syndrome that significantly contributes to reduced quality of life and increased mortality among many cancer patients. Its multifactorial nature makes its early diagnosis and effective therapeutic interventions challenging. Adipose tissue is particularly impacted by cachexia, typically through increased lipolysis, browning and thermogenesis, mainly at the onset of the disease. These processes lead to depletion of fat mass and contribute to the dysfunction of other organs. The ß-adrenergic signalling pathways are classical players in the regulation of adipose tissue metabolism. They are activated upon sympathetic stimulation inducing lipolysis, browning and thermogenesis, therefore contributing to energy expenditure. Despite accumulating evidence suggesting that ß3-adrenergic receptor stimulation may be crucial to the adipose tissue remodelling during cachexia, the literature remains controversial. Moreover, there is limited knowledge regarding sexual dimorphism of adipose tissue in the context of cachexia. This review paper aims to present the current knowledge regarding adipose tissue wasting during CAC, with a specific focus on the role of the ß3-adrenergic receptor, placing it as a potential therapeutic target against cachexia.

Map of thrombogenesis in viral infections and viral-driven tumours.

Viruses are pathogenic agents responsible for approximately 10% of all human cancers and significantly contribute to the global cancer burden. Until now, eight viruses have been associated with the development of a broad range of malignancies, including solid and haematological tumours. Besides triggering and promoting oncogenesis, viral infections often go hand-in-hand with haemostatic changes, representing a potential risk factor for venous thromboembolism (VTE). Conversely, VTE is a cardiovascular condition that is particularly common among oncological patients, with a detrimental impact on patient prognosis. Despite an association between viral infections and coagulopathies, it is unclear whether viral-driven tumours have a different incidence and prognosis pattern of thromboembolism compared to non-viral-induced tumours. Thus, this review aims to analyse the existing evidence concerning the association of viruses and viral tumours with the occurrence of VTE. Except for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection, which are associated with a high risk of VTE, little evidence exists concerning the thrombogenic potential associated with oncoviruses. As for tumours that can be induced by oncoviruses, four levels of VTE risk are observed, with hepatocellular carcinoma (HCC) and gastric carcinoma (GC) associated with the highest risk and nasopharyngeal carcinoma (NPC) associated with the lowest risk. Unfortunately, the incidence of cancer-related VTE according to tumour aetiology is unknown. Given the negative impact of VTE in oncological patients, research is required to better understand the mechanisms underlying blood hypercoagulability in viral-driven tumours to improve VTE management and prognosis assessment in patients diagnosed with these tumours.

Thrombosis and cachexia in cancer: Two partners in crime?

Among cancer patients, thrombosis and cachexia are major causes of morbidity and mortality. Although the two may occur together, little is known about their possible relationship. Thus, a literature review was conducted by screening the databases PubMed, Scopus, SciELO, Medline and Web of Science. To summarize, cancer-associated thrombosis (CAT) and cancer-associated cachexia (CAC) seem to share several patient-, tumour- and treatment-related risk factors. Inflammation alongside metabolic and endocrine derangement is the potential missing link between CAT, CAC and cancer. Many key players, including specific pro-inflammatory cytokines, immune cells and hormones, appear to be implicated in both thrombosis and cachexia, representing attractive predictive markers and potential therapeutic targets. Altogether, the current evidence suggests a link between CAT and CAC, however, epidemiological studies are required to explore this potential relationship. Given the high incidence and negative impact of both diseases, further studies are needed for the better management of cancer patients.

Malignancy Associated with Low-Risk HPV6 and HPV11: A Systematic Review and Implications for Cancer Prevention.

High-risk human papillomavirus (HPV) is etiologically related to cervical cancer, other anogenital cancers and oropharyngeal carcinomas. Low-risk HPV, especially HPV6 and HPV11, cause genital warts and laryngeal papillomas. However, the accumulating data suggests that HPV6 and HPV11 may cause malignant lesions at non-cervical anatomic sites. This review aims to estimate the proportions of single and dual HPV6/11 infections in multiple cancers reported in the last 10 years in the Cochrane, Embasa and PubMed databases. Secondly, the genomes of HPV6/11 were compared with the most common high-risk genotype, HPV16, to determine the similarities and differences. A total of 11 articles were selected, including between one and 334 HPV+ cancer patients. The frequencies of single or dual HPV6/11 infections ranged between 0-5.5% for penile and 0-87.5% for laryngeal cancers and were null for vulvar, vaginal and oral cancers. The genomic similarities between HPV6/11 and HPV16 mainly involved the E7 gene, indicating a limited ability to block cell differentiation. The presence of single or dual HPV6/11 infections in variable proportions of penile and laryngeal cancers support the vaccination strategies that cover these genotypes, not only for preventing genital warts but also for cancer prevention. Other risk factors and co-carcinogens are likely to participate in epithelial carcinogenesis associated with low-risk HPV.

Invasion factors are coupled to key signalling events leading to the establishment of infection in apicomplexan parasites.

Invasion of host cells by apicomplexan parasites is initiated when specialized secretory organelles called micronemes discharge protein complexes onto the parasite surface in response to a rise in parasite intracellular calcium levels. The microneme proteins establish interactions with host cell receptors, engaging the parasite with the host cell surface, and signal for the immediate exocytosis of another set of secretory organelles named the rhoptries. The rhoptry proteins reprogram the invaded host cell and participate in the formation of the parasitophorous vacuole in which the intracellular parasite resides and replicates. Disengagement of the invading parasite from the host cell receptors involves the action of at least one parasite plasma membrane rhomboid protease, which is concomitantly implicated in a checkpoint that signals the parasite to switch from an invasive to a replicative mode.

Decolorization and mineralization of reactive dyes by a photocatalytic process using ZnO and UV radiation.

Reactive dyes are one of the major pollutants in textile wastewater and a concern because they are not easily degraded by conventional wastewater treatments. Heterogeneous photocatalysis has been considered an effective option for treating wastewater containing those dyes. This research work assesses the photocatalytic degradation of reactive dyes using UV irradiation and pure or impregnated ZnO. In addition to photocatalysis, separate photolysis and adsorption experiments were conducted but showed low efficiency. The dye degradation was monitored by UV-Vis spectroscopy and mineralization was determined by total organic carbon (TOC) analyses. Total color removal was achieved after 30 min of irradiation using pure ZnO. The Black 5 dye photocatalytic decolorization reaction followed first-order kinetics, while Yellow 145, Red 4 and Blue 21 dyes followed zero-order kinetics. TOC removals in the range of 70-80% were achieved after 240 min of individual photocatalytic treatment with ZnO. The performance of each photocatalyst was also compared when the four dyes were mixed together and the order of efficiency in the mineralization process was as follows: Fe/ZnO > ZnO > Co/ZnO. This result was explained by the crystal field theory.

Decoding the role of inflammation-related microRNAs in cancer cachexia: a study using HPV16-transgenic mice and in silico approaches.

Cachexia is associated with poor prognosis in cancer patients, and inflammation is one of its main drive factors. MicroRNAs have recently emerged as important players in cancer cachexia and are involved in reciprocal regulation networks with pro-inflammatory signaling pathways. We hypothesize that inflammation-driven cancer cachexia is regulated by specific microRNAs. The aim of this study is to explore the expression and role of inflammation-related microRNAs in muscle wasting. HPV16-transgenic mice develop systemic inflammation and muscle wasting and are a model for cancer cachexia. We employed gastrocnemius muscle samples from these mice to study the expression of microRNAs. Bioinformatic tools were then used to explore their potential role in muscle wasting. Among the microRNAs studied, miR-223-3p (p = 0.004), let-7b-5p (p = 0.034), miR-21a-5p (p = 0.034), miR-150-5p (p = 0.027), and miR-155-5p (p = 0.011) were significantly upregulated in muscles from cachectic mice. In silico analysis showed that these microRNAs participate in several processes related to muscle wasting, including muscle structure development and regulation of the MAPK pathway. When analyzing protein-protein interactions (PPI)-networks, two major clusters and the top 10 hubs were obtained. From the top 10, Kras (p = 0.050) and Ccdn1 (p = 0.009) were downregulated in cachectic muscles, as well as Map2k3 (p = 0.007). These results show that miR-223-3p, let-7b-5p, miR-21a-5p, miR-150-5p, and miR-155-5p, play a role in muscle wasting in HPV16 transgenic mice, possible through regulating the MAPK cascades. Future experimental studies are required to validate our in silico analysis, and to explore the usefulness of these microRNAs and MAPK signaling as new potential biomarkers or therapy targets for cancer cachexia.

Characterizing the Inflammatory Microenvironment in K14-HPV16 Transgenic Mice: Mast Cell Infiltration and MicroRNA Expression.

High-risk human papillomavirus (HPV) is the etiologic agent of several types of cancer. Mast cells' role as either a driving or opposing force for cancer progression remains controversial. MicroRNAs are dysregulated in several HPV-induced cancers, and can influence mast cell biology. The aim of this study was to evaluate mast cell infiltration and to identify microRNAs potentially regulating this process. Transgenic male mice (K14-HPV16; HPV+) and matched wild-type mice (HPV−) received 7,12-Dimethylbenz[a]anthracene (DMBA) (or vehicle) over 17 weeks. Following euthanasia, chest skin and ear tissue samples were collected. Mast cell infiltration was evaluated by immunohistochemistry. MicroRNAs associated with mast cell infiltration were identified using bioinformatic tools. MicroRNA and mRNA relative expression was evaluated by RT-qPCR. Immunohistochemistry showed increased mast cell infiltration in HPV+ mice (p < 0.001). DMBA did not have any statistically significant influence on this distribution. Ear tissue of HPV+ mice showed increased mast cell infiltration (p < 0.01) when compared with chest skin samples. Additionally, reduced relative expression of miR-125b-5p (p = 0.008, 2−ΔΔCt = 2.09) and miR-223-3p (p = 0.013, 2−ΔΔCt = 4.42) seems to be associated with mast cell infiltration and increased expression of target gene Cxcl10. These results indicate that HPV16 may increase mast cell infiltration by down-regulating miR-223-3p and miR-125b-5p.

Expression of LncRNAs in HPV-induced Carcinogenesis and Cancer Cachexia: A Study in K14-HPV16 Mice.

AIM: To evaluate the expression of lincRNA-p21, H19, EMX2OS, SNHG12 and MALAT1 in a mouse model of human papillomavirus 16 (HPV16)-induced carcinogenesis and cachexia. MATERIALS AND METHODS: Chest skin, ear, tongue, penis and gastrocnemius muscle samples from wild-type mice (HPV-) and K14-HPV16 male mice (HPV+) were collected to evaluate the expression of the selected lncRNAs using real-time PCR (qPCR). RESULTS: In chest skin and ear, H19, SNHG12, EMX2OS and lincRNA-p21 were down-regulated in HPV+ versus HPV- mice. In tongue and penile tissues, there was only down-regulation of lincRNA-p21 in HPV+ mice. Additionally, in penile tissue, lincRNA-p21 expression decreased in HPV-induced lesions comparing with normal tissues. In gastrocnemius muscle, MALAT1 was up-regulated and lincRNA-p21 was down-regulated in HPV+ versus HPV-mice. CONCLUSION: H19, SNHG12, EMX2OS and lincRNA-p21 may be involved in HPV-induced carcinogenesis. In addition, MALAT1 and lincRNA-p21 may play a role in muscle wasting and contribute to cancer cachexia.

Ketoacidosis in new-onset type 1 diabetes: did the severity increase during the COVID-19 pandemic?

OBJECTIVES: Since the beginning of the COVID-19 pandemic, there has been a consistent decrease in the number of admissions to the emergency department, leading to a delay in the diagnosis of several pathologies. The time from onset of symptoms to the diagnosis of Type 1 diabetes is highly variable. This treatment delay can lead to the appearance of ketoacidosis. METHODS: Retrospective study of inaugural Type 1 diabetes cases, from March 2016 to March 2021. The pandemic group was considered between March 2020 to March 2021, and the remaining period was considered as pre-pandemic. Clinical variables were analysed: duration of symptoms, weight loss and value of ketonemia and glycated haemoglobin on admission. The mean differences were considered statistically significant at p<0.05. RESULTS: 103 inaugural episodes of Type 1 diabetes were registered. The pandemic group had a lower mean age when compared to pre-pandemic group, and 51.7% of the episodes had ketoacidosis with a higher relative risk of ketoacidosis and severe ketoacidosis, when compared the pandemic with pre-pandemic group, there was a longer symptom evolution time (34 vs. 20 days), greater weight loss occurred (9.5% vs. 6.3%), the pH and HCO3 - values were lower (7.30 vs. 7.36 and 16.43 vs. 20.71 mmol/L respectively) and ketonemia was higher (5.9 vs. 2.3 mmol/L). CONCLUSIONS: The COVID-19 pandemic caused a delay in the diagnosis of Type 1 diabetes, greater length of disease, greater weight loss, higher ketonemia and lower pH and HCO3 -. There was greater ketoacidosis relative risk in pandemic group when compared to pre-pandemic group.

Members of a novel protein family containing microneme adhesive repeat domains act as sialic acid-binding lectins during host cell invasion by apicomplexan parasites.

Numerous intracellular pathogens exploit cell surface glycoconjugates for host cell recognition and entry. Unlike bacteria and viruses, Toxoplasma gondii and other parasites of the phylum Apicomplexa actively invade host cells, and this process critically depends on adhesins (microneme proteins) released onto the parasite surface from intracellular organelles called micronemes (MIC). The microneme adhesive repeat (MAR) domain of T. gondii MIC1 (TgMIC1) recognizes sialic acid (Sia), a key determinant on the host cell surface for invasion by this pathogen. By complementation and invasion assays, we demonstrate that TgMIC1 is one important player in Sia-dependent invasion and that another novel Sia-binding lectin, designated TgMIC13, is also involved. Using BLAST searches, we identify a family of MAR-containing proteins in enteroparasitic coccidians, a subclass of apicomplexans, including T. gondii, suggesting that all these parasites exploit sialylated glycoconjugates on host cells as determinants for enteric invasion. Furthermore, this protein family might provide a basis for the broad host cell range observed for coccidians that form tissue cysts during chronic infection. Carbohydrate microarray analyses, corroborated by structural considerations, show that TgMIC13, TgMIC1, and its homologue Neospora caninum MIC1 (NcMIC1) share a preference for alpha2-3- over alpha2-6-linked sialyl-N-acetyllactosamine sequences. However, the three lectins also display differences in binding preferences. Intense binding of TgMIC13 to alpha2-9-linked disialyl sequence reported on embryonal cells and relatively strong binding to 4-O-acetylated-Sia found on gut epithelium and binding of NcMIC1 to 6'sulfo-sialyl Lewis(x) might have implications for tissue tropism.

Toxoplasma gondii transmembrane microneme proteins and their modular design.

Host cell invasion by the Apicomplexa critically relies on regulated secretion of transmembrane micronemal proteins (TM-MICs). Toxoplasma gondii possesses functionally non-redundant MIC complexes that participate in gliding motility, host cell attachment, moving junction formation, rhoptry secretion and invasion. The TM-MICs are released onto the parasite's surface as complexes capable of interacting with host cell receptors. Additionally, TgMIC2 simultaneously connects to the actomyosin system via binding to aldolase. During invasion these adhesive complexes are shed from the surface notably via intramembrane cleavage of the TM-MICs by a rhomboid protease. Some TM-MICs act as escorters and assure trafficking of the complexes to the micronemes. We have investigated the properties of TgMIC6, TgMIC8, TgMIC8.2, TgAMA1 and the new micronemal protein TgMIC16 with respect to interaction with aldolase, susceptibility to rhomboid cleavage and presence of trafficking signals. We conclude that several TM-MICs lack targeting information within their C-terminal domains, indicating that trafficking depends on yet unidentified proteins interacting with their ectodomains. Most TM-MICs serve as substrates for a rhomboid protease and some of them are able to bind to aldolase. We also show that the residues responsible for binding to aldolase are essential for TgAMA1 but dispensable for TgMIC6 function during invasion.