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Competing Interests: The authors report no conflicts of interest.

Men who have sex with men (MSM), regardless of HIV infection status, have an intestinal microbiome that is compositionally distinct from men who have sex with women (MSW) and women. We recently showed HIV-negative MSM have elevated levels of intestinal CD4 + T cells expressing CCR5, a critical co-receptor for HIV. Whether elevated expression of CCR5 is driven by the altered gut microbiome composition in MSM has not been explored. Here we used in vitro stimulation of gut Lamina Propria Mononuclear Cells (LPMCs) with whole intact microbial cells isolated from stool to demonstrate that fecal bacterial communities (FBCs) from HIV-positive/negative MSM induced higher frequencies of CCR5 + CD4 + T cells compared to FBCs from HIV-negative MSW and women. To identify potential microbial drivers, we related the frequency of CCR5 + CD4 + T cells to the abundance of individual microbial taxa in rectal biopsy of HIV-positive/negative MSM and controls, and Holdemanella biformis was strongly associated with increased frequency of CCR5 + CD4 + T cells. We used in vitro stimulation of gut LPMCs with the type strain of H. biformis , a second strain of H. biformis and an isolate of the closely related Holdemanella porci , cultured from either a HIV-positive or a HIV-negative MSM stool. H. porci elevated the frequency of both CCR5 + CD4 + T cells and the ratio of TNF-α/IL-10 Genomic comparisons of the 3  Holdemanella isolates revealed unique cell wall and capsular components, which may be responsible for their differences in immunogenicity. These findings describe a novel mechanism potentially linking intestinal dysbiosis in MSM to HIV transmission and mucosal pathogenesis.

Gaining a complete understanding of transmission risk factors will assist in efforts to reduce new HIV infections, especially within the disproportionally affected population of men who have sex with men (MSM). We recently reported that the fecal microbiota of MSM elevates immune activation in gnotobiotic mice and enhances HIV infection in vitro over that of fecal microbiota from men who have sex with women. We also demonstrated elevation of the gut homing marker CD103 (integrin αE) on CD4 + T cells by MSM-microbiota. Here we provide additional evidence that the gut microbiota is a risk factor for HIV transmission in MSM by showing elevated frequencies of the HIV co-receptor CCR5 on CD4 + T cells in human rectosigmoid colon biopsies. We discuss our interest in specific MSM-associated bacteria and propose the influx of CD103 + and CCR5 + CD4 + T cells into the colon as a potential link between the MSM microbiota and HIV transmission.

Rh alloimmunization remains a challenge for patients with sickle cell disease (SCD) despite transfusion of serologic Rh C, E, and K antigen-matched red cells. Inheritance of altered RH alleles contributes to the prevalence of Rh antibodies after blood transfusion in patients with SCD and explains approximately one-third of cases. The remainder seem to be stimulated by altered Rh proteins on African American donor red cells. Matching patients with donors on the basis of RH genotype may mitigate Rh alloimmunization, but the feasibility and resources required are not known. We compared RH allele frequencies between patients with SCD (n = 857) and African American donors (n = 587) and showed that RH allele frequencies are similar. Overall, 29% of RHD and 53% of RHCE alleles are altered in patients and African American donors. We modeled RH genotype matching compared with serologic Rh D, C, and E, along with K antigen matching, and found that approximately twice the number of African American donors would be required for RH genotype vs Rh serologic matching at our institution. We demonstrated that African American donor recruitment is necessary to maintain an adequate supply of C-, E-, and K-negative donor units to avoid depleting the Rh-negative (RhD - ) blood supply. Our results suggest that prophylactic RH genetic matching for patients with SCD is feasible with a donor pool comprised primarily of African-Americans and would optimize the use of our existing minority donor inventory. The current cost of RH genotyping all minority donors and management of the data remain limiting factors., (© 2018 by The American Society of Hematology.)

Allergic asthma is an inflammatory lung disease that is partly sustained by the chemokine eotaxin-3 (CCL26), which extends eosinophil migration into tissues long after allergen exposure. Modulation of CCL26 could represent a means to mitigate airway inflammation. Here we evaluated procyanidin A2 as a means of modulating CCL26 production and investigated interactions with the known inflammation modulator, Interferon γ (IFNγ). We used the human lung epithelial cell line A549 and optimized the conditions for inducing CCL26. Cells were exposed to a range of procyanidin A2 or IFNγ concentrations for varied lengths of time prior to an inflammatory insult of interleukin-4 (IL-4) for 24 h. An enzyme-linked immunosorbent assay was used to measure CCL26 production. Exposing cells to 5 μM procyanidin A2 (prior to IL-4) reduced CCL26 production by 35% compared with control. Greatest inhibition by procyanidin A2 was seen with a 2 h exposure prior to IL-4, whereas IFNγ inhibition was greatest at 24 h. Concomitant incubation of procyanidin A2 and IFNγ did not extend the inhibitory efficacy of procyanidin A2. These data provide evidence that procyanidin A2 can modulate IL-4-induced CCL26 production by A549 lung epithelial cells and that it does so in a manner that is different from IFNγ., Competing Interests: The authors declare no conflict of interest. The funding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

Hyaluronan (HA) is a linear glycosaminoglycan of the vertebrate extracellular matrix that is synthesized at the plasma membrane by the HA synthase (HAS) enzymes HAS1, -2 and -3. The regulation of HA synthesis has been implicated in a variety of extracellular matrix-mediated and pathological processes, including renal fibrosis. We have recently described the genomic structures of each of the human HAS genes. In the present study, we analyzed the HAS2 promoter region. In 5'-rapid amplification of cDNA ends analysis of purified mRNA from human renal epithelial proximal tubular cells, we detected an extended sequence for HAS2 exon 1, relocating the transcription initiation site 130 nucleotides upstream of the reference HAS2 mRNA sequence, GenBank accession number NM_005328. A luciferase reporter gene assay of nested fragments spanning the 5' terminus of NM_005328 demonstrated the constitutive promoter activity of sequences directly upstream of the repositioned transcription initiation site but not of the newly designated exonic nucleotides. Using reverse transcription-PCR, expression of this extended HAS2 mRNA was demonstrated in a variety of human cell types, and orthologous sequences were detected in mouse and rat kidney. Alignment of human, murine, and equine genomic DNA sequences upstream of the repositioned HAS2 exon 1 provided evidence for the evolutionary conservation of specific transcription factor binding sites. The location of the HAS2 promoter will facilitate analysis of the transcriptional regulation of this gene in a variety of pathological contexts as well as in developmental models in which HAS2 null animals have an embryonic lethal phenotype.

We have sought to obtain an unbiased estimate of the proportion of polymorphisms in promoters of human genes that have functional effects. We carried out polymorphism discovery on a randomly selected group of 51 gene promoters mapping to human chromosome 21 and successfully analyzed the effect on transcription of 38 of the sequence variants. To achieve this, a total of 53 different haplotypes from 20 promoters were cloned into a modified pGL3 luciferase reporter gene vector and were tested for their abilities to promote transcription in HEK293t and JEG-3 cells. Up to seven (18%) of the 38 tested variants altered transcription by 1.5-fold, confirming that a surprisingly high proportion of promoter region polymorphisms are likely to be functionally important. The functional variants were distributed across the promoters of CRYAA, IFNAR1, KCNJ15, NCAM2, IGSF5, and B3GALT5. Three of the genes (NCAM2, IFNAR1, and CRYAA) have been previously associated with human phenotypes and the polymorphisms we describe here may therefore play a role in those phenotypes.

Gephyrin (GPHN) is an organizational protein that clusters and localizes the inhibitory glycine (GlyR) and GABAA receptors to the microtubular matrix of the neuronal postsynaptic membrane. Mice deficient in gephyrin develop a hereditary molybdenum cofactor deficiency and a neurological phenotype that mimics startle disease (hyperekplexia). This neuromotor disorder is associated with mutations in the GlyR alpha1 and beta subunit genes (GLRA1 and GLRB). Further genetic heterogeneity is suspected, and we hypothesized that patients lacking mutations in GLRA1 and GLRB might have mutations in the gephyrin gene (GPHN). In addition, we adopted a yeast two-hybrid screen, using the GlyR beta subunit intracellular loop as bait, in an attempt to identify further GlyR-interacting proteins implicated in hyperekplexia. Gephyrin cDNAs were isolated, and subsequent RT-PCR analysis from human tissues demonstrated the presence of five alternatively spliced GPHN exons concentrated in the central linker region of the gene. This region generated 11 distinct GPHN transcript isoforms, with 10 being specific to neuronal tissue. Mutation analysis of GPHN exons in hyperekplexia patients revealed a missense mutation (A28T) in one patient causing an amino acid substitution (N10Y). Functional testing demonstrated that GPHNN10Y does not disrupt GlyR-gephyrin interactions or collybistininduced cell-surface clustering. We provide evidence that GlyR-gephyrin binding is dependent on the presence of an intact C-terminal MoeA homology domain. Therefore, the N10Y mutation and alternative splicing of GPHN transcripts do not affect interactions with GlyRs but may affect other interactions with the cytoskeleton or gephyrin accessory proteins.

We have developed a rapid method for identifying functional promoter-region polymorphisms. Using a modified pGL3 luciferase expression T-vector, we can amplify by PCR, clone, identify allelic pairs of a polymorphic gene promoter region, and prepare plasmids for cell culture 10 promoters (20 allele pairs) per week per researcher. By utilizing 96-well plate technology and an internal control plasmid expressing secreted alkaline phosphatase, each of these allele pairs can be tested for relative promoter activity in each of three cell lines (HEK293t, TE671, and JEG3) with similar resources.

This study was undertaken to obtain direct evidence for the involvement of gap junctions in the propagation of intercellular Ca(2+) waves. Gap junction-deficient HeLa cells were transfected with plasmids encoding for green fluorescent protein (GFP) fused to the cytoplasmic carboxyl termini of connexin 43 (Cx43), 32 (Cx32), or 26 (Cx26). The subsequently expressed GFP-labeled gap junctions rendered the cells dye- and electrically coupled and were detected at the plasma membranes at points of contact between adjacent cells. To correlate the distribution of gap junctions with the changes in [Ca(2+)](i) associated with Ca(2+) waves and the distribution of the endoplasmic reticulum (ER), cells were loaded with fluorescent Ca(2+)-sensitive (fluo-3 and fura-2) and ER membrane (ER-Tracker) dyes. Digital high-speed microscopy was used to collect a series of image slices from which the three-dimensional distribution of the gap junctions and ER were reconstructed. Subsequently, intercellular Ca(2+) waves were induced in these cells by mechanical stimulation with or without extracellular apyrase, an ATP-degrading enzyme. In untransfected HeLa cells and in the absence of apyrase, cell-to-cell propagating [Ca(2+)](i) changes were characterized by initiating Ca(2+) puffs associated with the perinuclear ER. By contrast, in Cx-GFP-transfected cells and in the presence of apyrase, [Ca(2+)](i) changes were propagated without initiating perinuclear Ca(2+) puffs and were communicated between cells at the sites of the Cx-GFP gap junctions. The efficiency of Cx expression determined the extent of Ca(2+) wave propagation. These results demonstrate that intercellular Ca(2+) waves may be propagated simultaneously via an extracellular pathway and an intracellular pathway through gap junctions and that one form of communication may mask the other.