A. Al-Hendy

A Preliminary Study: Human Fibroid Stro-1+/CD44+ Stem Cells Isolated From Uterine Fibroids Demonstrate Decreased DNA Repair and Genomic Integrity Compared to Adjacent Myometrial Stro-1+/CD44+ Cells

Context: Although uterine fibroids (UFs) continue to place a major burden on female reproductive health, the mechanisms behind their origin remain undetermined. Normal myometrial stem cells may be transformed into tumor-initiating stem cells, causing UFs, due to unknown causes of somatic mutations in MED12, found in up to 85% of sporadically formed UFs. It is well established in other tumor types that defective DNA repair increases the risk of such tumorigenic somatic mutations, mechanisms not yet studied in UFs. Objective: To examine the putative cause(s) of this stem cell transformation, we analyzed DNA repair within stem cells from human UFs compared to those from adjacent myometrium to determine whether DNA repair in fibroid stem cells is compromised. Design: Human fibroid (F) and adjacent myometrial (Myo) stem cells were isolated from fresh tissues, and gene expression relating to DNA repair was analyzed. Fibroid stem cells differentially expressed DNA repair genes related to DNA double- (DSBs) and single-strand breaks. DNA damage was measured using alkaline comet assay. Additionally, DNA DSBs were induced in these stem cells and DNA DSB repair evaluated (1) by determining changes in phosphorylation of DNA DSB-related proteins and (2) by determining differences in γ-H2AX foci formation and relative DNA repair protein RAD50 expression. Results: Overall, F stem cells demonstrated increased DNA damage and altered DNA repair gene expression and signaling, suggesting that human F stem cells demonstrate impaired DNA repair. Conclusions: Compromised F stem cell DNA repair may contribute to further mutagenesis and, consequently, further growth and propagation of UF tumors.

PDL-1 blockade prevents T cell exhaustion, inhibits autophagy, and promotes clearance of Leishmania donovani

ABSTRACT Leishmania donovani is a causative pathogen of potentially fatal visceral leishmaniasis (VL). Therapeutic agents are available; however, their use is limited because of high cost, serious side effects, and development of antimicrobial resistance. Protective immunity against VL depends on CD4+ Th1 cell-mediated immunity. Studies have shown that progression of VL is due to exhaustion of T cells; however, the mechanism involved is not clearly understood. Here, we examined the role of PD1/PDL-1 in the pathogenesis of VL by using a murine model of VL. Our data indicate that L. donovani is able to elicit initial expansion of gamma interferon-producing CD4+ Th1 and CD8+ T cells at day 7 postinfection (p.i.); however, the frequency of those cells and inflammatory response decreased at day 21 p.i., despite persistence of parasites. Persistent infection-induced expansion of interleukin-10+ FOXP3+ Treg and CD4+ and CD8+ T cells expressing PD1. Blocking of PDL-1 signaling in vivo resulted in restoration of protective type 1 responses by both CD4+ and CD8+ T cells, which resulted in a significant decrease in the parasite burden. Mechanistically, PDL-1 blocking inhibited autophagy, a cellular degradation process hijacked by Leishmania to acquire host cell nutrients for their survival. Inhibition of autophagy was marked by decreased lipidation of microtubule-associated protein 1 light chain 3, a marker of autophagosome formation, and P62 accumulation. Together, our findings show for the first time that anti-PDL-1 antibody is an effective therapeutic approach for restoration of effector arms of protective immunity against VL and subsequent parasite clearance.

Endocrine disruptor exposure during development increases incidence of uterine fibroids by altering DNA repair in myometrial stem cells

Abstract Despite the major negative impact uterine fibroids (UFs) have on female reproductive health, little is known about early events that initiate development of these tumors. Somatic fibroid-causing mutations in mediator complex subunit 12 (MED12), the most frequent genetic alterations in UFs (up to 85% of tumors), are implicated in transforming normal myometrial stem cells (MSCs) into tumor-forming cells, though the underlying mechanism(s) leading to these mutations remains unknown. It is well accepted that defective DNA repair increases the risk of acquiring tumor-driving mutations, though defects in DNA repair have not been explored in UF tumorigenesis. In the Eker rat UF model, a germline mutation in the Tsc2 tumor suppressor gene predisposes to UFs, which arise due to “second hits” in the normal allele of this gene. Risk for developing these tumors is significantly increased by early-life exposure to endocrine-disrupting chemicals (EDCs), suggesting increased UF penetrance is modulated by early drivers for these tumors. We analyzed DNA repair capacity using analyses of related gene and protein expression and DNA repair function in MSCs from adult rats exposed during uterine development to the model EDC diethylstilbestrol. Adult MSCs isolated from developmentally exposed rats demonstrated decreased DNA end-joining ability, higher levels of DNA damage, and impaired ability to repair DNA double-strand breaks relative to MSCs from age-matched, vehicle-exposed rats. These data suggest that early-life developmental EDC exposure alters these MSCs ability to repair and reverse DNA damage, providing a driver for acquisition of mutations that may promote the development of these tumors in adult life. Summary Sentence Effects of perinatal endocrine disruptor-exposure on DNA repair of adult rat myometrial stem cells(MSCs) were examined. MSCs from exposed animals showed increased DNA damage and diminished DNA repair.

Uterine fibroid therapy: the pharmacokinetic considerations

Uterine fibroids (UFs, AKA; leiomyoma) are the most prevalent benign neoplastic threat in reproductive age women. Ultrasound based epidemiological studies disclosed that 70 −80% of these women will develop UFs by age of 50. Although inherently benign, this enigmatic disease constitutes a major health and financial burden worldwide, also, it presents a major health disparity challenge for being at least four times more common in women of color [1]. UFs associated symptoms negatively impact daily living as well as overall quality of life of approximately 20–30% of afflicted patients. This includes abnormal uterine bleeding with subsequent anemia, bulk symptoms, obstetrical complications and recently possible infertility [1,2]. Despite the high prevalence and health significance of UFs, we know surprisingly little about its underlying cause or pathogenesis. This reflects the limited availability of safe long-term anti-UF treatment options. Historically, Hysterectomy has been the most common treatment option for symptomatic UFs. Yet, many factors halt that preference including, its invasive nature as well as uterus and consequently fertility deprivation [1,2]. In regard to alternatives like pharmacological treatment, unfortunately, majority of the current therapies offer inadequate or short-term control of symptoms and cannot be used for long term because of safety concerns [3]. In this editorial we will glimpse the important medical treatment options for UF, either approved or in the pipeline, with emphasis on their pharmacokinetic (PK) features that certainly can shape the future of UF treatment development.

Expanding upon the Human Myometrial Stem Cell Hypothesis and the Role of Race, Hormones, Age, and Parity in a Profibroid Environment

Uterine fibroids (UFs) are clonal, hormonally regulated, benign smooth-muscle myometrial tumors that severely affect female reproductive health, although their unknown etiology limits effective care. UFs occur fourfold more commonly in African American women than in Caucasian women, and African American women generally have earlier disease onset and greater UF tumor burden, although the mechanism of this ethnic disparity has not been identified. Recent findings have linked cancer (ie,xa0tumor) risk to increased tissue-specific stem cell division and self-renewal and suggest that somatic mutations in myometrial stem cells (MyoSCs) convert them into tumor-initiating cells, leading to UF. Specifically, preliminary results in paraffin-embedded myometrial tissues have shown increased STRO-1+/CD44+ MyoSCs in African American versus Caucasian women. Using specific methods of flow cytometry and automated quantitative pathology imaging, a large cohort of myometrial samples were investigated to determine how the STRO-1+/CD44+ MyoSCs change with regard to a patients race, age, parity, fibroid and hormone statuses, and the location of UFs within the uterus. We confirmed that the STRO-1+/CD44+ MyoSC population is expanded in African American women, is correlated with parity and fibroid number, and fluctuates with cyclic menstrual cycle hormone changes and age. Our data suggest that an expanded MyoSC population increases the formation of tumor-initiating cells, ultimately contributing to increased UF prevalence and burden in African American women.