Prevalence and Diversity of Haplotypes of Sickle Cell Disease in the Eastern Province of Saudi Arabia.

Hb F modulates sickle cell disease. Five major haplotypes of the ß-globin gene cluster are associated with sickle cell disease. In the Eastern Province of Saudi Arabia, the Arab-Indian (AI) is most common. Single nucleotide polymorphism (SNP) genotyping (rs3834466, rs28440105, rs10128556, and rs968857) was carried out by nuclease allelic discrimination assay with target-specific forward and reverse primers, TaqMan probes, labeled with VIC and FAM. In 778 patients with sickle cell disease from the Eastern Province, a haplotype was assigned to 90.9% of all samples; 9.1% were classified as compound heterozygotes for the AI and an atypical haplotype. The distribution of haplotypes for 746 Hb S (HBB: c.20A > T) homozygotes was: 614 AI/AI, nine SEN/SEN (Senegal), 42 SEN/AI, nine CAM/CAM (Cameroon), one CAR (Central African Republic)/BEN (Benin), 71 AI/atypical. In Hb S/ß-thalassemia (Hb S/ß-thal), the distribution of Hb S haplotypes was: 22 AI/AI, one CAM/CAM, four AI/SEN, five AI/atypical. Mean Hb F in the haplotypes was: AI/AI 16.6 ± 7.5%, CAM/CAM 8.0 ± 4.1%, SEN/SEN 11.0 ± 5.1%, SEN/AI 15.1 ± 4.6%, AI/atypical 16.2 ± 6.5%. The presence of the SEN and CAM haplotypes was unexpected due to the apparent homogeneity of the population of the Eastern Province. We have successfully classified sickle cell disease haplotypes using the relatively inexpensive TaqMan assay for the first time. In addition, we have previously shown that children with AI haplotype have Hb F of 30.0% and mild disease, while in our cohort of adult AI patients, which might be the largest yet reported, Hb F was about 16.6%.

Atypical Skeletal Muscle Profiles in Human Immunodeficiency Virus-Infected Asymptomatic Middle-Aged Adults.

Background: Human immunodeficiency virus (HIV)-infected individuals are at increased risk of age-associated functional impairment, even with effective antiretroviral therapy (ART). A concurrent characterization of skeletal muscle, physical function, and immune phenotype in aviremic middle-aged HIV-infected adults represents a knowledge gap in prognostic biomarker discovery. Methods: We undertook a prospective observational study of 170 middle-aged, HIV-infected ambulatory men and women with CD4+ T-cell counts of at least 350/µL and undetectable plasma viremia while on effective ART, and uninfected control participants. We measured biomarkers for inflammation and immune activation, fatigue, the Veterans Aging Cohort Study mortality index, and physical function. A subset also received a skeletal muscle biopsy and computed tomography scan. Results: Compared to the uninfected participants, HIV-infected participants displayed increased immune activation (P < .001), inflammation (P = .001), and fatigue (P = .010), and in a regression model adjusting for age and sex displayed deficits in stair-climb power (P < .001), gait speed (P = .036), and predicted metabolic equivalents (P = .019). Skeletal muscle displayed reduced nuclear peroxisome proliferator-activated receptor-γ coactivator 1α-positive myonuclei (P = .006), and increased internalized myonuclei (P < .001) that correlated with immune activation (P = .003) and leukocyte infiltration (P < .001). Internalized myonuclei improved a model for HIV discrimination, increasing the C-statistic from 0.84 to 0.90. Conclusions: Asymptomatic HIV-infected middle-aged adults display atypical skeletal muscle profiles, subclinical deficits in physical function, and persistent inflammation and immune activation. Identifying biomarker profiles for muscle dysregulation and risk for future functional decline in the HIV-infected population will be key to developing and monitoring preventive interventions. Clinical Trials Registration: NCT03011957.

Assessing known chronic kidney disease associated genetic variants in Saudi Arabian populations.

BACKGROUND: Genome wide association studies of patients with European descent have identified common variants associated with risk of reduced estimated glomerular filtration rate (eGFR). A panel of eight variants were selected to evaluate their association and prevalence in a Saudi Arabian patient cohort with chronic kidney disease (CKD). METHODS: Eight genetic variants in four genes (SHROOM3, MYH9, SLC7A9, and CST3) were genotyped in 160 CKD patients and 189 ethnicity-matched healthy controls. Genetic variants were tested for association with the development of CKD (eGFR < 60 ml/min/1.73m2) and effects were compared with results obtained from 133,413 participants in the CKD genetics consortium. Multivariable regression was used to evaluate the role of these eight variants in improving prediction of CKD development. RESULTS: All eight variants were present in Saudi populations with minor allele frequency ranging from 16 to 46%. The risk variant in all four genes demonstrated the same direction of effect as observed in European populations. One variant, rs4821480, in MYH9 was significantly associated with increased risk of development of CKD (OR = 1.69, 95% CI 1.22-2.36, P = 0.002), but the additional variants were not statistically significant given our modest sample size. CONCLUSIONS: CKD risk variants identified in European populations are present in Saudis. We did not find evidence to suggest heterogeneity of effect size compared to previously published estimates in European populations. Multivariable logistic regression analysis showed a statistically significant improvement in predicting the CKD using models with either FGF23 and vitamin D or FGF23, vitamin D level, and MYH9 genotypes (AUC = 0.93, 95% CI 0.90-0.95, P <  0.0001).

Inhalation therapy with M1 inhibits experimental melanoma development and metastases in mice.

BACKGROUND: M1 is a homeopathic medicine with immunostimulatory properties used mainly by cancer patients to complement current therapies. Metastatic melanoma is a skin-originated form of cancer without a single therapy able to produce high rate and sustained responses, which attracts the use of complementary therapies such as M1. However, M1's anti-melanoma effects remain to be pre-clinically demonstrated. Therefore in the present work, we utilized a pulmonary metastatic melanoma model and a subcutaneous melanoma growth model to investigate the potential benefits of treatment with M1. METHODS: C57BL/6 mice were injected intravenously or subcutaneously with B16F10 mouse melanoma cells. After 24 h, mice were treated with either M1 or vehicle (water) for 14 days, euthanized and harvested for multi-parameter pulmonary and tumor analyses. RESULTS: Mice treated with M1 had significantly lower tumor burden in the lungs and subcutaneous tissue than control mice. Furthermore, tumors were impaired in proliferation and tumor related angiogenesis by the inhibition of myeloid derived suppressor cells (MDSC) positive for angiotensin II type 1 receptor (AT1R). CONCLUSION: Altogether these data suggest M1 is an efficient candidate for melanoma therapy to be considered for future clinic studies as this study is the first supporting the idea that melanoma patients may benefit with the treatment. The treatment with M1 provides advantages considering the highly-diluted properties and a cost effective alternative to costly chemotherapeutic approaches with, if any, lower toxicity.

Plasmacytoid dendritic cells engagement by influenza vaccine as a surrogate strategy for driving T-helper type 1 responses in human neonatal settings.

BACKGROUND: The elicitation of T-helper type 1 (Th1) cellular immunity to eradicate intracellular pathogens is a challenging task because of the interleukin 12 (IL-12) deficit observed in early infancy. METHODS: Screening cord blood responses to various pediatric vaccines and Toll-like receptor (TLR) agonists for innate responses and CD4(+) T-cell differentiation. RESULTS: We identified that nonadjuvanted inactivated trivalent influenza vaccine (TIV) was able to cosignal T cells for the production of interferon γ (IFN-γ) in a neonatal setting. This process includes the mobilization of neonatal plasmacytoid dendritic cells (pDCs) as antigen-presenting cells (APCs) that efficiently engage Th1 cells in an IL-12-independent but type I IFN-dependent manner. In addition, cord blood pDCs efficiently cross-presented antigen to CD8(+) T cells. Importantly, activation by TIV mainly requires TLR7; however, R848/TLR7- and CpGB/TLR9-activated pDCs, which poorly produced IFN-α, induce neonatal Th2 responses. CONCLUSIONS: TLR pathway engagement in pDCs is necessary but not sufficient for a successful neonatal Th1 outcome. We provide evidence of a mature and functional neonatal immune system at the level of APCs and T cells and propose to implement the IFN-α/IFN-γ axis in pediatric vaccination as a surrogate for the defective IL-12/IFN-γ axis.

Mitochondrial DNA polymerase POLIB is essential for minicircle DNA replication in African trypanosomes.

The unique mitochondrial DNA of trypanosomes is a catenated network of minicircles and maxicircles called kinetoplast DNA (kDNA). The network is essential for survival, and requires an elaborate topoisomerase-mediated release and reattachment mechanism for minicircle theta structure replication. At least seven DNA polymerases (pols) are involved in kDNA transactions, including three essential proteins related to bacterial DNA pol I (POLIB, POLIC and POLID). How Trypanosoma brucei utilizes multiple DNA pols to complete the topologically complex task of kDNA replication is unknown. To fill this gap in knowledge we investigated the cellular role of POLIB using RNA interference (RNAi). POLIB silencing resulted in growth inhibition and progressive loss of kDNA networks. Additionally, unreplicated covalently closed precursors become the most abundant minicircle replication intermediate as minicircle copy number declines. Leading and lagging strand minicircle progeny similarly declined during POLIB silencing, indicating POLIB had no apparent strand preference. Interestingly, POLIB RNAi led to the accumulation of a novel population of free minicircles that is composed mainly of covalently closed minicircle dimers. Based on these data, we propose that POLIB performs an essential role at the core of the minicircle replication machinery.

Stem-loop silencing reveals that a third mitochondrial DNA polymerase, POLID, is required for kinetoplast DNA replication in trypanosomes.

Kinetoplast DNA (kDNA), the mitochondrial genome of trypanosomes, is a catenated network containing thousands of minicircles and tens of maxicircles. The topological complexity dictates some unusual features including a topoisomerase-mediated release-and-reattachment mechanism for minicircle replication and at least six mitochondrial DNA polymerases (Pols) for kDNA transactions. Previously, we identified four family A DNA Pols from Trypanosoma brucei with similarity to bacterial DNA Pol I and demonstrated that two (POLIB and POLIC) were essential for maintaining the kDNA network, while POLIA was not. Here, we used RNA interference to investigate the function of POLID in procyclic T. brucei. Stem-loop silencing of POLID resulted in growth arrest and the progressive loss of the kDNA network. Additional defects in kDNA replication included a rapid decline in minicircle and maxicircle abundance and a transient accumulation of minicircle replication intermediates before loss of the kDNA network. These results demonstrate that POLID is a third essential DNA Pol required for kDNA replication. While other eukaryotes utilize a single DNA Pol (Pol gamma) for replication of mitochondrial DNA, T. brucei requires at least three to maintain the complex kDNA network.

Perspective: A Novel Prognostic for Sickle Cell Disease.

Sickle hemoglobin (α2ßS 2) polymerization drives disease pathophysiology in sickle cell anemia. Fetal hemoglobin (α2γ2) restricts disease severity by inhibiting the polymerization of sickle hemoglobin in a concentration-dependent manner. Clinical decision-making relies on diagnostic technologies evaluating fetal hemoglobin as mean percent or mean quantity in blood. Limitation of this approach is exemplified by patients with significant high fetal hemoglobin levels and severe disease, suggesting that fetal hemoglobin is unevenly distributed across F-cells. Therefore, determination of fetal hemoglobin/F-cell would provide a new paradigm for ascertaining prognosis and response to fetal hemoglobin-inducing agents. Measurement of fetal hemoglobin/F-cell, ultimately adapted to widespread standardized analytical use, is a promising fetal hemoglobin-related prognostic approach to monitor the severity of sickle cell disease and the best "phenotype" to follow when developing new candidate fetal hemoglobin inducers or titrating hydroxyurea in treated sickle cell patients.

B lymphocytes undergo TLR2-dependent apoptosis upon Shigella infection.

Antibody-mediated immunity to Shigella, the causative agent of bacillary dysentery, requires several episodes of infection to get primed and is short-lasting, suggesting that the B cell response is functionally impaired. We show that upon ex vivo infection of human colonic tissue, invasive S. flexneri interacts with and occasionally invades B lymphocytes. The induction of a type three secretion apparatus (T3SA)-dependent B cell death is observed in the human CL-01 B cell line in vitro, as well as in mouse B lymphocytes in vivo. In addition to cell death occurring in Shigella-invaded CL-01 B lymphocytes, we provide evidence that the T3SA needle tip protein IpaD can induce cell death in noninvaded cells. IpaD binds to and induces B cell apoptosis via TLR2, a signaling receptor thus far considered to result in activation of B lymphocytes. The presence of bacterial co-signals is required to sensitize B cells to apoptosis and to up-regulate tlr2, thus enhancing IpaD binding. Apoptotic B lymphocytes in contact with Shigella-IpaD are detected in rectal biopsies of infected individuals. This study therefore adds direct B lymphocyte targeting to the diversity of mechanisms used by Shigella to dampen the host immune response.

CD4 T cells with effector memory phenotype and function develop in the sterile environment of the fetus.

The T cell compartment is considered to be naïve and dedicated to the development of tolerance during fetal development. We have identified and characterized a population of fetally developed CD4 T cells with an effector memory phenotype (TEM), which are present in cord blood. This population is polyclonal and has phenotypic features similar to those of conventional adult memory T cells, such as CD45RO expression. These cells express low levels of CD25 but are distinct from regulatory T cells because they lack Foxp3 expression. After T cell receptor activation, neonatal TEM cells readily produced tumor necrosis factor-α (TNF-α) and granulocyte-macrophage colony-stimulating factor (GM-CSF). We also detected interferon-γ (IFN-γ)-producing T helper 1 (TH1) cells and interleukin-4 (IL-4)/IL-13-producing TH2-like cells, but not IL-17-producing cells. We used chemokine receptor expression patterns to divide this TEM population into different subsets and identified distinct transcriptional programs using whole-genome microarray analysis. IFN-γ was found in CXCR3(+) TEM cells, whereas IL-4 was found in both CXCR3(+) TEM cells and CCR4(+) TEM cells. CCR6(+) TEM cells displayed a genetic signature that corresponded to TH17 cells but failed to produce IL-17A. However, the TH17 function of TEM cells was observed in the presence of IL-1ß and IL-23. In summary, in the absence of reported pathology or any major infectious history, T cells with a memory-like phenotype develop in an environment thought to be sterile during fetal development and display a large variety of inflammatory effector functions associated with CD4 TH cells at birth.