Gene-by-gene screen of the unknown proteins encoded on Plasmodium falciparum chromosome 3.

Taxon-specific proteins are key determinants defining the biology of all organisms and represent prime drug targets in pathogens. However, lacking comparability with proteins in other lineages makes them particularly difficult to study. In malaria parasites, this is exacerbated by technical limitations. Here, we analyzed the cellular location, essentiality, function, and, in selected cases, interactome of all unknown non-secretory proteins encoded on an entire P. falciparum chromosome. The nucleus was the most common localization, indicating that it is a hotspot of parasite-specific biology. More in-depth functional studies with four proteins revealed essential roles in DNA replication and mitosis. The mitosis proteins defined a possible orphan complex and a highly diverged complex needed for spindle-kinetochore connection. Structure-function comparisons indicated that the taxon-specific proteins evolved by different mechanisms. This work demonstrates the feasibility of gene-by-gene screens to elucidate the biology of malaria parasites and reveal critical parasite-specific processes of interest as drug targets.

Proximity-dependent biotinylation approaches to study apicomplexan biology.

In the last 10 years, proximity-dependent biotinylation (PDB) techniques greatly expanded the ability to study protein environments in the living cell that range from specific protein complexes to entire compartments. This is achieved by using enzymes such as BirA* and APEX that are fused to proteins of interest and biotinylate proteins in their proximity. PDB techniques are now also increasingly used in apicomplexan parasites. In this review, we first give an overview of the main PDB approaches and how they compare with other techniques that address similar questions. PDB is particularly valuable to detect weak or transient protein associations under physiological conditions and to study cellular structures that are difficult to purify or have a poorly understood protein composition. We also highlight new developments such as novel smaller or faster-acting enzyme variants and conditional PDB approaches, providing improvements in both temporal and spatial resolution which may offer broader application possibilities useful in apicomplexan research. In the second part, we review work using PDB techniques in apicomplexan parasites and how this expanded our knowledge about these medically important parasites.

Identification of novel inner membrane complex and apical annuli proteins of the malaria parasite Plasmodium falciparum.

The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers stability and shape to the cell, functions as a scaffolding compartment during the formation of daughter cells and plays an important role in motility and invasion during different life cycle stages of these single-celled organisms. To explore the IMC proteome of the malaria parasite Plasmodium falciparum we applied a proximity-dependent biotin identification (BioID)-based proteomics approach, using the established IMC marker protein Photosensitized INA-Labelled protein 1 (PhIL1) as bait in asexual blood-stage parasites. Subsequent mass spectrometry-based peptide identification revealed enrichment of 12 known IMC proteins and several uncharacterized candidate proteins. We validated nine of these previously uncharacterized proteins by endogenous GFP-tagging. Six of these represent new IMC proteins, while three proteins have a distinct apical localization that most likely represents structures described as apical annuli in Toxoplasma gondii. Additionally, various Kelch13 interacting candidates were identified, suggesting an association of the Kelch13 compartment and the IMC in schizont and merozoite stages. This work extends the number of validated IMC proteins in the malaria parasite and reveals for the first time the existence of apical annuli proteins in P. falciparum. Additionally, it provides evidence for a spatial association between the Kelch13 compartment and the IMC in late blood-stage parasites.

Ustekinumab Does Not Increase Risk of Adverse Events: A Meta-Analysis of Randomized Controlled Trials.

GOALS AND BACKGROUND: Ustekinumab (UST) is a monoclonal antibody inhibitor of IL-12/IL-23 approved for the treatment of Crohn's disease (CD) and ulcerative colitis (UC). We conducted a meta-analysis to compare rates of adverse events (AEs) in randomized controlled trials (RCTs) of UST for all indications. STUDY: A systematic search was performed of MEDLINE, Embase, and PubMed databases through November 2019. Study inclusion included RCTs comparing UST to placebo or other biologics in patients aged 18 years or older with a diagnosis of an autoimmune condition. RESULTS: Thirty RCTs with 16,068 patients were included in our analysis. Nine thousand six hundred and twenty-six subjects were included in the UST vs placebo analysis. There was no significant difference in serious or mild/moderate AEs between UST and placebo with an OR of 0.83 (95% CI 0.66, 1.05) and 1.08 (95% CI 0.99, 1.18), respectively, over a median follow-up time of 16 weeks. In a sub-analysis of CD and UC trials, no difference in serious or mild/moderate AEs in UST versus placebo was seen. CONCLUSIONS: UST was not associated with an increase in short-term risk of AEs.

The Complex Interplay Between Inflammatory Bowel Disease and Malignancy.

PURPOSE OF REVIEW: Both the chronic inflammation in inflammatory bowel disease (IBD), and its treatment, can increase the risk of malignancy. There is also an increasing number of patients with current and prior cancer who require IBD treatment. Thus, there is a complex interplay between immunosuppressive treatment and monitoring for new and recurrent cancer. RECENT FINDINGS: Vedolizumab and ustekinumab have not been shown to increase the risk of malignancy. Transplant data shows a potential risk with tofacitinib although rheumatoid arthritis data does not. IBD patients have been shown to tolerate chemotherapy, specifically with cytotoxic compared with hormonal chemotherapy. Patients with prior cancer are at increased risk of new or recurrent cancers; however, immunosuppression appears to be safe. Emerging treatments for IBD have demonstrated acceptable safety profiles for malignancy risk, and immunosuppression appears to be safe for use in patients with current and prior malignancy. More data is still needed to assess long-term risk of malignancy in these patients, especially with newer treatments.

Gastric Solitary Fibrous Tumor Causing Upper Gastrointestinal Bleeding.

We present an 81-year-old woman with remote breast cancer who presented with melena and hemorrhagic shock requiring intensive care hospitalization. Endoscopic evaluation showed a 5-cm pedunculated gastric mass with ulceration and friability. She underwent sleeve gastrectomy for definitive treatment of her bleeding. Pathology was consistent with a solitary fibrous tumor (SFT). There are only a few reported cases of gastric SFTs presenting with gastrointestinal bleeding. If a large brown/tan bleeding mass is identified on upper endoscopy, SFT should be considered.

Loss of Peristaltic Reserve, Determined by Multiple Rapid Swallows, Is the Most Frequent Esophageal Motility Abnormality in Patients With Systemic Sclerosis.

We assessed peristaltic reserve using multiple rapid swallows (MRS) during esophageal high-resolution manometry (HRM) of 111 patients with systemic sclerosis (89 women; ages, 42-64 y). We performed a retrospective analysis of HRM studies that included MRS in patients with systemic sclerosis, performed at 2 tertiary referral centers, and compared data with those from 18 healthy volunteers (controls). HRM findings were analyzed according to the Chicago Classification to provide an esophageal motility diagnosis. Response to MRS was evaluated for the presence of contraction and for augmentation, defined as the distal contractile integral after MRS greater than the median distal contractile integral of 10 supine swallows. Esophageal motility diagnoses included 41% with absent contractility, 31% with normal motility, 23% with ineffective esophageal motility, and 5% that met the criteria for other esophageal motility disorders. Contraction (37%) and peristaltic augmentation (18%) after MRS were observed less frequently in patients with systemic sclerosis than in controls (83% and 100%, respectively). Impaired peristaltic reserve, as assessed with MRS during HRM, is therefore the most common esophageal motility finding among patients with systemic sclerosis.

Inflammatory Bowel Disease and Skin Cancer: An Assessment of Patient Risk Factors, Knowledge, and Skin Practices.

Objective. Patients with inflammatory bowel disease (IBD) are at increased risk from skin cancer. Aims include assessing IBD patients' risk factors and knowledge of skin cancer and current skin protection practices to identify gaps in patient education regarding skin cancer prevention in IBD. Methods. IBD patients ≥ 18 years were recruited to complete an online survey. Results. 164 patients (mean age 43.5 years, 63% female) with IBD (67% Crohn's disease, 31% ulcerative colitis, and 2% indeterminate colitis) were included. 12% (n = 19) of patients had a personal history and 34% (n = 55) had a family history of skin cancer. Females scored better on skin protection (16.94/32 versus 14.53/32, P ≤ 0.03) and awareness (35.16/40 versus 32.98/40, P ≤ 0.03). Patients over 40 years old scored better on prevention (17.45/28 versus 15.35/28, P = 0.03). Patients with skin cancer scored better on prevention (20.56/28 versus 15.75/28, P ≤ 0.001) and skin protection (21.47/32 versus 15.33/32, P ≤ 0.001). 61% of patients recognized the link between skin cancer and IBD. Conclusions. The majority of IBD patients are aware of the link between skin cancer and IBD; however, skin protection practices are suboptimal. This emphasizes the role of healthcare professionals in providing further education for skin cancer prevention in the IBD population.

Chronic high-fat diet drives postnatal epigenetic regulation of µ-opioid receptor in the brain.

Opioid system dysregulation has been observed in both genetic and high-fat diet (HFD)-induced models of obesity. An understanding of the molecular mechanisms of MOR transcriptional regulation, particularly within an in vivo context, is lacking. Using a diet-induced model of obesity (DIO), mice were fed a high-fat diet (60% calories from fat) from weaning to >18 weeks of age. Compared with mice fed the control diet, DIO mice had a decreased preference for sucrose. MOR mRNA expression was decreased in reward-related circuitry (ventral tegmental area (VTA), nucleus accumbens (NAc), and prefrontal cortex (PFC)) but not the hypothalamus, important in the homeostatic regulation of feeding. DNA methylation is an epigenetic modification that links environmental exposures to altered gene expression. We found a significant increase in DNA methylation in the MOR promoter region within the reward-related brain regions. Methyl CpG-binding protein 2 (MeCP2) can bind methylated DNA and repress transcription, and DIO mice showed increased binding of MeCP2 to the MOR promoter in reward-related regions of the brain. Finally, using ChIP assays we examined H3K9 methylation (inactive chromatin) and H3 acetylation (active chromatin) within the MOR promoter region and found increased H3K9 methylation and decreased H3 acetylation. These data are the first to identify DNA methylation, MeCP2 recruitment, and chromatin remodeling as mechanisms leading to transcriptional repression of MOR in the brains of mice fed a high-fat diet.

Maternal high-fat diet alters methylation and gene expression of dopamine and opioid-related genes.

Maternal obesity during pregnancy increases the risk of obesity in the offspring. Obesity, arising from an imbalance of energy intake and expenditure, can be driven by the ingestion of palatable [high fat (HF), high sugar], energy-dense foods. Dopamine and opioid circuitry are neural substrates associated with reward that can affect animals' preference for palatable foods. Using a mouse model, the long-term effect of maternal consumption of a HF diet on dopamine and opioid gene expression within the mesocorticolimbic reward circuitry and hypothalamus of the offspring was investigated. Mice from dams fed a HF diet during pregnancy and lactation showed an increased preference for sucrose and fat. Gene expression, measured using quantitative real-time PCR, revealed a significant approximately 3- to 10-fold up-regulation of dopamine reuptake transporter (DAT) in the ventral tegmental area, nucleus accumbens, and prefrontal cortex and a down-regulation of DAT in the hypothalamus. Additionally, expression of both µ-opioid receptor (MOR) and preproenkephalin (PENK) was increased in nucleus accumbens, prefrontal cortex, and hypothalamus of mice from dams that consumed the HF diet. Epigenetic mechanisms have been associated with long-term programming of gene expression after various in utero insults. We observed global and gene-specific (DAT, MOR, and PENK) promoter DNA hypomethylation in the brains of offspring from dams that consumed the HF diet. These data demonstrate that maternal consumption of a HF diet can change the offsprings' epigenetic marks (DNA hypomethylation) in association with long-term alterations in gene expression (dopamine and opioids) and behavior (preference for palatable foods).