IL-27: An endogenous constitutive repressor of human monocytes.

Interleukin (IL)-27 is a pleiotropic cytokine that initially was described as being pro-inflammatory and an inducer of T helper (Th)1 cells. In contrast, it has also been described as an anti-inflammatory cytokine in that it suppresses pro-inflammatory Th17 cells and induces anti-inflammatory IL-10 producing T regulatory (Tr)1 cells. While the majority of studies have been focused on the effects of IL-27 on T cells, human antigen-presenting cells express high levels of the IL-27 receptor ex vivo, in addition to being the major producer of IL-27. We report here that human monocytes are repressed by endogenous IL-27, in that the addition of an anti-IL-27 neutralizing antibody increases the production of pro-inflammatory cytokines ex vivo. We observed that neutralizing monocyte-derived IL-27 leads to increased IL-17A production by CD4+ T cells and a down-regulation of the IL-17 modulating ectonucleotidase CD39 on monocytes. The locus that contains the IL27 gene has been linked to susceptibility for type 1 diabetes (T1D). Interestingly, ex vivo monocytes from subjects with T1D produce more IL-27 suggesting this upregulation of IL-27 acts as a negative feedback loop to attempt to counterbalance the pro-inflammatory immune response in the disease state. In summary, we provide evidence that IL-27 is an endogenous regulator of human monocytes and has consequences on CD4+ T cell phenotype, particularly Th17 cells.

Rheumatoid arthritis-associated RBPJ polymorphism alters memory CD4+ T cells.

Notch signaling has recently emerged as an important regulator of immune responses in autoimmune diseases. The recombination signal-binding protein for immunoglobulin kappa J region (RBPJ) is a transcriptional repressor, but converts into a transcriptional activator upon activation of the canonical Notch pathway. Genome-wide association studies of rheumatoid arthritis (RA) identified a susceptibility locus, rs874040(CC), which implicated the RBPJ gene. Here, chromatin state mapping generated using the chromHMM algorithm reveals strong enhancer regions containing DNase I hypersensitive sites overlapping the rs874040 linkage disequilibrium block in human memory, but not in naïve CD4(+) T cells. The rs874040 overlapping this chromatin state was associated with increased RBPJ expression in stimulated memory CD4(+) T cells from healthy subjects homozygous for the risk allele (CC) compared with memory CD4(+) T cells bearing the protective allele (GG). Transcriptomic analysis of rs874040(CC) memory T cells showed a repression of canonical Notch target genes IL (interleukin)-9, IL-17 and interferon (IFN)γ in the basal state. Interestingly, activation of the Notch pathway using soluble Notch ligand, Jagged2-Fc, induced IL-9 and IL-17A while delta-like 4Fc, another Notch ligand, induced higher IFNγ expression in the rs874040(CC) memory CD4(+) T cells compared with their rs874040(GG) counterparts. In RA, RBPJ expression is elevated in memory T cells from RA patients compared with control subjects, and this was associated with induced inflammatory cytokines IL-9, IL-17A and IFNγ in response to Notch ligation in vitro. These findings demonstrate that the rs874040(CC) allele skews memory T cells toward a pro-inflammatory phenotype involving Notch signaling, thus increasing the susceptibility to develop RA.

BCL6 controls Th9 cell development by repressing Il9 transcription.

The transcriptional repressor B cell lymphoma 6 (BCL6) is required for the development of Th follicular cells, and it has been shown to suppress Th2 cell differentiation. We demonstrate that BCL6 is a key regulator of Th9 cell development. BCL6 expression is transiently downregulated in polarized Th9 cells, and forced expression of BCL6 in Th9 cells impairs Th9 cell differentiation. In contrast, BCL6 knockdown upregulated IL-9 production in Th9 cells. The function of BCL6 in Th9 cells is under the control of IL-2/JAK3/STAT5 signaling pathway. Using chromatin immunoprecipitation, we show that, in Th9 cells, BCL6 and STAT5 bind to adjacent motifs in the Il9 promoter. Furthermore, we found that STAT5 binding was associated with the abundance of a permissive histone mark at the Il9 promoter, whereas under conditions in which BCL6 binding was predominant, a repressive histone mark was prevalent. The effects of STAT5 and BCL6 on IL-9 transcription were further demonstrated using an IL-9 luciferase reporter assay in which BCL6 repressed STAT5-mediated Il9 transactivation. In experimental autoimmune encephalomyelitis, forced expression of BCL6 in myelin oligodendrocyte glycoprotein35-55-specific Th9 cells resulted in decreased IL-9 production and induction of IFN-γ, causing an exacerbation of the clinical disease. Our findings demonstrate a novel role of BCL6 in the regulation of Th9 cell development and their encephalitogenicity.

A novel 2q37 microdeletion containing human neural progenitors genes including STK25 results in severe developmental delay, epilepsy, and microcephaly.

2q37 microdeletion syndrome is a rare syndrome characterized by neurodevelopmental delay, bone, cardiovascular, and neurological alterations. This syndrome is typically associated with loss of genetic material of approximately 100 genes in the 2q37 band. However, the genes associated with neurodevelopmental phenotype in this syndrome are still unknown. We identified a deleted region of 496 kb by whole genome array CGH in a patient who fulfilled criteria for 2q37 microdeletion syndrome with developmental delay, microcephaly, hypoplasia of the corpus callosum, hand wringing, toe walking, and seizures. The deleted segment contains genes that are highly expressed in the developing human cortical plate and the subventricular zone (SVZ) in vivo and human neural progenitors in vitro, including SEPT2, THAP4, ATG4B, PPP1R7, and STK25. Network analysis revealed that STK25 was the most interacting gene associated with neural development in this deletion. Our report narrows the likely causative genomic region for microcephaly and neurodevelopmental delay in 2q37 microdeletion syndrome to a small genomic region enriched with neural progenitor genes that may represent an important locus for the development of the human cortex and corpus callosum.

Safety and feasibility of the three-port robot-assisted hysterectomy across uterine weights.

One strategy thought to reduce direct costs associated with robotic surgery is minimizing the number of robotic arms used for a surgery. We aim to demonstrate the safety and feasibility of the three-port robot-assisted hysterectomy across uterine weights. Retrospective cohort study in a tertiary care university hospital of consecutive patients undergoing a three-port robot-assisted hysterectomy for benign indications. All surgeries were performed between 2012 and 2018 by fellowship-trained minimally invasive gynecologic surgeons. Data from 232 patients were collected. Eighty-eight (37.9%) patients had a uterine weight < 250 g, 63 (27.2%) had a uterine weight between 250 and 500 g, 51 (22.0%) had a uterine weight between 500 and 1000 g, and 30 (12.9%) had a uterine weight ≥ 1000 g. Multivariable regression analysis revealed no statistically significant differences between uterine weight groups and time spent in PACU, the total length of hospital stay, or direct cost. When setting the < 250 g as referent, patients with uterine weights between 500 and 1000 g, and more than 1000 g had an operative time that was on average 23.4% and 91.6% longer than patients with uterine weight < 250 g, respectively (p < 0.01). Patients with uterine weights between 500 and 1000 g and more than 1000 g had an EBL that was on average 35% and 156% higher than patients with uterine weight < 250 g, respectively (p < 0.01). Our data support the safety and feasibility of the three-port robot-assisted hysterectomy technique across uterine weights.

Perinatal outcomes of women undergoing cesarean delivery after prior myomectomy.

Background: The American College of Obstetricians and Gynecologists recommends that women who have had a prior myomectomy that entered the endometrial cavity undergo cesarean delivery in order to avoid the possible complication of uterine rupture. Women with prior myomectomies may also have intraabdominal adhesions, complicating future surgery and if myomas remain after myomectomy, they may have more bleeding complications during their subsequent pregnancies.Objectives: The purpose of this study was to evaluate maternal and neonatal outcomes after prior myomectomy in women undergoing planned cesarean delivery.Study design: We conducted a retrospective cohort study using the Maternal Fetal Medicine Units Cesarean Registry database comparing women undergoing a cesarean delivery with a history of prior myomectomy to women undergoing a cesarean delivery without a history of a prior myomectomy. Inclusion criteria were singleton gestations at term undergoing planned cesarean delivery. Exclusion criteria were stillbirth, cesarean delivery indication for nonreassuring fetal heart rate, macrosomia, abruption, previa or women undergoing planned trial of labor after cesarean. Primary outcome was incidence of blood transfusion. Maternal and neonatal outcomes were compared secondarily. Logistic regression was used to adjust for confounders.Results: The entire study population included 73,257 deliveries; 34,002 women met inclusion criteria, of which 367 had a prior myomectomy and 33,635 were controls. The demographics, which varied by maternal age, race and number of prior cesareans were adjusted for when calculating maternal outcomes. The rate of intraoperative transfusion in the prior myomectomy group was 1.4% (5/367) compared to 0.4% (131/33,635) in the control group (aOR 2.8; 95% CI 1.15-6.79). The prior myomectomy group had a higher incidence of postpartum transfusion rate (2.5%, 9/367) compared to the control group (1.2%, 416/33,635) (aOR 2.03; 1.06-3.92), uterotonic usage (5.4%, 20/367) compared to the control group (3.5%, 1165/33,635; aOR 1.57; 95% CI 1.01-2.45), bowel injury (0.5%, 2/367) compared to the control group (0.0%, 14/33,635; aOR 8.13; 95% CI 2.05-32.28) and cesarean hysterectomy (1.4%, 5/367) compared to the control group (77/33,635; aOR 3.43; 95% CI 1.32-8.91). Neonatal outcomes were not different between groups.Conclusion: Prior myomectomy in women with term, singleton gestations undergoing planned cesarean delivery was associated with an 180% increased risk of intraoperative transfusion compared to the control group. We also found that women in the myomectomy group are 57% more likely to use uterotonics, 713% more likely to experience a bowel injury, 243% more likely to undergo a cesarean hysterectomy, and 227% more likely to need a classical uterine incision during delivery. Neonatal morbidity was not statistically different between the groups.

A transcriptomic atlas of aged human microglia.

With a rapidly aging global human population, finding a cure for late onset neurodegenerative diseases has become an urgent enterprise. However, these efforts are hindered by the lack of understanding of what constitutes the phenotype of aged human microglia-the cell type that has been strongly implicated by genetic studies in the pathogenesis of age-related neurodegenerative disease. Here, we establish the set of genes that is preferentially expressed by microglia in the aged human brain. This HuMi_Aged gene set captures a unique phenotype, which we confirm at the protein level. Furthermore, we find this gene set to be enriched in susceptibility genes for Alzheimer's disease and multiple sclerosis, to be increased with advancing age, and to be reduced by the protective APOEε2 haplotype. APOEε4 has no effect. These findings confirm the existence of an aging-related microglial phenotype in the aged human brain and its involvement in the pathological processes associated with brain aging.

A human microglia-like cellular model for assessing the effects of neurodegenerative disease gene variants.

Microglia are emerging as a key cell type in neurodegenerative diseases, yet human microglia are challenging to study in vitro. We developed an in vitro cell model system composed of human monocyte-derived microglia-like (MDMi) cells that recapitulated key aspects of microglia phenotype and function. We then used this model system to perform an expression quantitative trait locus (eQTL) study examining 94 genes from loci associated with Alzheimer's disease, Parkinson's disease, and multiple sclerosis. We found six loci (CD33, PILRB, NUP160, LRRK2, RGS1, and METTL21B) in which the risk haplotype drives the association with both disease susceptibility and altered expression of a nearby gene (cis-eQTL). In the PILRB and LRRK2 loci, the cis-eQTL was found in the MDMi cells but not in human peripheral blood monocytes, suggesting that differentiation of monocytes into microglia-like cells led to the acquisition of a cellular state that could reveal the functional consequences of certain genetic variants. We further validated the effect of risk haplotypes at the protein level for PILRB and CD33, and we confirmed that the CD33 risk haplotype altered phagocytosis by the MDMi cells. We propose that increased LRRK2 gene expression by MDMi cells could be a functional outcome of rs76904798, a single-nucleotide polymorphism in the LRKK2 locus that is associated with Parkinson's disease.

Tiam1/Rac1 complex controls Il17a transcription and autoimmunity.

RORγt is a master transcription factor of Th17 cells and considered as a promising drug target for the treatment of autoimmune diseases. Here, we show the guanine nucleotide exchange factor, Tiam1, and its cognate Rho-family G protein, Rac1, regulate interleukin (IL)17A transcription and autoimmunity. Whereas Tiam1 genetic deficiency weakens IL-17A expression partially and inhibits the development of experimental autoimmune encephalomyelitis (EAE), deletion of Rac1 in T cells exhibits more robust effects on Th17 cells and EAE. We demonstrate Tiam1 and Rac1 form a complex with RORγt in the nuclear compartment of Th17 cells, and together bind and activate the Il17 promoter. The clinical relevance of these findings is emphasized by pharmacological targeting of Rac1 that suppresses both murine and human Th17 cells as well as EAE. Thus, our findings highlight a regulatory pathway of Tiam1/Rac1 in Th17 cells and suggest that it may be a therapeutic target in multiple sclerosis.