Bashir M. Rezk

Neoplastic Reprogramming of Patient-Derived Adipose Stem Cells by Prostate Cancer Cell-Associated Exosomes

Emerging evidence suggests that mesenchymal stem cells (MSCs) are often recruited to tumor sites but their functional significance in tumor growth and disease progression remains elusive. Herein we report that prostate cancer (PC) cell microenvironment subverts PC patient adipose‐derived stem cells (pASCs) to undergo neoplastic transformation. Unlike normal ASCs, the pASCs primed with PC cell conditioned media (CM) formed prostate‐like neoplastic lesions in vivo and reproduced aggressive tumors in secondary recipients. The pASC tumors acquired cytogenetic aberrations and mesenchymal‐to‐epithelial transition and expressed epithelial, neoplastic, and vasculogenic markers reminiscent of molecular features of PC tumor xenografts. Our mechanistic studies revealed that PC cell‐derived exosomes are sufficient to recapitulate formation of prostate tumorigenic mimicry generated by CM‐primed pASCs in vivo. In addition to downregulation of the large tumor suppressor homolog2 and the programmed cell death protein 4, a neoplastic transformation inhibitor, the tumorigenic reprogramming of pASCs was associated with trafficking by PC cell‐derived exosomes of oncogenic factors, including H‐ras and K‐ras transcripts, oncomiRNAs miR‐125b, miR‐130b, and miR‐155 as well as the Ras superfamily of GTPases Rab1a, Rab1b, and Rab11a. Our findings implicate a new role for PC cell‐derived exosomes in clonal expansion of tumors through neoplastic reprogramming of tumor tropic ASCs in cancer patients. Stem Cells 2014;32:983–997

Angiotensin II induced catabolic effect and muscle atrophy are redox dependent

Angiotensin II (Ang II) causes skeletal muscle wasting via an increase in muscle catabolism. To determine whether the wasting effects of Ang II were related to its ability to increase NADPH oxidase-derived reactive oxygen species (ROS) we infused wild-type C57BL/6J or p47(phox)(-/-) mice with vehicle or Ang II for 7days. Superoxide production was increased 2.4-fold in the skeletal muscle of Ang II infused mice, and this increase was prevented in p47(phox)(-/-) mice. Apocynin treatment prevented Ang II-induced superoxide production in skeletal muscle, consistent with Ang II increasing NADPH oxidase derived ROS. Ang II induced loss of body and skeletal muscle weight in C57BL/6J mice, whereas the reduction was significantly attenuated in p47(phox)(-/-) animals. The reduction of skeletal muscle weight caused by Ang II was associated with an increase of proteasome activity, and this increase was completely prevented in the skeletal muscle of p47(phox)(-/-) mice. In conclusion, Ang II-induced skeletal muscle wasting is in part dependent on NADPH oxidase derived ROS.

Angiotensin II inhibits satellite cell proliferation and prevents skeletal muscle regeneration.

Background: Angiotensin II is elevated in cachexia and induces skeletal muscle atrophy. Results: Angiotensin inhibits muscle stem (satellite) cell proliferation via a Notch-dependent mechanism and depletes the satellite cell pool. Conclusion: Angiotensin prevents skeletal muscle regeneration by suppressing satellite cell function. Significance: This is the first report to show that satellite cells express angiotensin receptors and that angiotensin inhibits regeneration. Cachexia is a serious complication of many chronic diseases, such as congestive heart failure (CHF) and chronic kidney disease (CKD). Although patients with advanced CHF or CKD often have increased angiotensin II (Ang II) levels and cachexia and Ang II causes skeletal muscle wasting in rodents, the potential effects of Ang II on muscle regeneration are unknown. Muscle regeneration is highly dependent on the ability of a pool of muscle stem cells (satellite cells) to proliferate and to repair damaged myofibers or form new myofibers. Here we show that Ang II reduced skeletal muscle regeneration via inhibition of satellite cell (SC) proliferation. Ang II reduced the number of regenerating myofibers and decreased expression of SC proliferation/differentiation markers (MyoD, myogenin, and active-Notch) after cardiotoxin-induced muscle injury in vivo and in SCs cultured in vitro. Ang II depleted the basal pool of SCs, as detected in Myf5nLacZ/+ mice and by FACS sorting, and this effect was inhibited by Ang II AT1 receptor (AT1R) blockade and in AT1aR-null mice. AT1R was highly expressed in SCs, and Notch activation abrogated the AT1R-mediated antiproliferative effect of Ang II in cultured SCs. In mice that developed CHF postmyocardial infarction, there was skeletal muscle wasting and reduced SC numbers that were inhibited by AT1R blockade. Ang II inhibition of skeletal muscle regeneration via AT1 receptor-dependent suppression of SC Notch and MyoD signaling and proliferation is likely to play an important role in mechanisms leading to cachexia in chronic disease states such as CHF and CKD.

Angiotensin II infusion induces marked diaphragmatic skeletal muscle atrophy.

Advanced congestive heart failure (CHF) and chronic kidney disease (CKD) are characterized by increased angiotensin II (Ang II) levels and are often accompanied by significant skeletal muscle wasting that negatively impacts mortality and morbidity. Both CHF and CKD patients have respiratory muscle dysfunction, however the potential effects of Ang II on respiratory muscles are unknown. We investigated the effects of Ang II on diaphragm muscle in FVB mice. Ang II induced significant diaphragm muscle wasting (18.7±1.6% decrease in weight at one week) and reduction in fiber cross-sectional area. Expression of the E3 ubiquitin ligases atrogin-1 and muscle ring finger-1 (MuRF-1) and of the pro-apoptotic factor BAX was increased after 24 h of Ang II infusion (4.4±0.3 fold, 3.1±0.5 fold and 1.6±0.2 fold, respectively, compared to sham infused control) suggesting increased muscle protein degradation and apoptosis. In Ang II infused animals, there was significant regeneration of injured diaphragm muscles at 7 days as indicated by an increase in the number of myofibers with centralized nuclei and high expression of embryonic myosin heavy chain (E-MyHC, 11.2±3.3 fold increase) and of the satellite cell marker M-cadherin (59.2±22.2% increase). Furthermore, there was an increase in expression of insulin-like growth factor-1 (IGF-1, 1.8±0.3 fold increase) in Ang II infused diaphragm, suggesting the involvement of IGF-1 in diaphragm muscle regeneration. Bone-marrow transplantation experiments indicated that although there was recruitment of bone-marrow derived cells to the injured diaphragm in Ang II infused mice (267.0±74.6% increase), those cells did not express markers of muscle stem cells or regenerating myofibers. In conclusion, Ang II causes marked diaphragm muscle wasting, which may be important for the pathophysiology of respiratory muscle dysfunction and cachexia in conditions such as CHF and CKD.

Pioglitazone’s beneficial effects on erectile function preservation after cavernosal nerve injury in the rat are negated by inhibition of the insulin-like growth factor-1 receptor: a preclinical study

To determine if the insulin-like growth factor-1 (IGF-1) pathway is involved in the improvement in erectile function recovery in rats after nerve crush injury treated with pioglitazone (Pio). Sprague-Dawley rats were divided into four groups. The first group received sham operation (n = 5). The second group underwent bilateral cavernous nerve injury (BCNI, n  = 7). The third group received BCNI and Pio treatment (BCNI  +  Pio, n = 7), whereas the fourth group underwent BCNI with Pio treatment and IGF-1 inhibition (BCNI  +  Pio  +  JB-1, n = 7). The IGF-1 receptor (IGF-1R) was inhibited by JB-1, a small molecular antagonist of the receptor. After 14 days of treatment, erectile function was measured via intracorporal pressure normalized to mean arterial pressure (ICP/MAP) and the major pelvic ganglion and cavernous nerve harvested for western blot and immunohistochemistry (IHC) of phosphorylated-IGF-1Rβ (p-IGF-1Rβ), phosphorylated-ERK1/2 (p-ERK1/2), and neuronal NOS (nNOS). BCNI  +  Pio animals exhibited improvements in ICP/MAP, similar to Sham animals, and BCNI  +  Pio  +  JB-1 rats demonstrated a reduced ICP/MAP similar to BCNI-only rats at all measured voltages. Western blot results showed upregulation of p-IGF-1Rβ was observed in the BCNI  +  Pio group. Low levels of p-ERK1/2 were seen in the JB-1-treated animals. The immunoblot results were supported by IHC findings. Intense IHC staining of nNOS was detected in the BCNI  +  Pio group. The group treated with JB-1 showed minimal protein expression of p-ERK1/2, nNOS, and p-IGF-1Rβ. Pio improves erectile function in rats undergoing BCNI via an IGF-1-mediated pathway.

Chapter 30 – Effects of Electronic Cigarettes on Men’s Reproductive and Sexual Health

Abstract Electronic cigarettes (e-cigarettes) are devices designed to imitate conventional cigarettes and to deliver nicotine via inhalation without the toxicants of regular tobacco. The rationale of e-cigarettes invention is to reduce the toxicity associated with conventional cigarettes. However, few toxicity studies have been performed to evaluate the chemical nature of vapor generated from e-cigarettes and its impact on human health. Since their emergence in 2004, e-cigarettes have become widely available, and their use has increased exponentially worldwide. Calls to poison control centers about e-cigarette toxicity have been attributed to e-cigarettes. In May 2016, the Food and Drug Administration approved new regulations to prohibit minors from purchasing e-cigarettes in person or online. The benefits and risks of e-cigarette use are a subject of discussion among health organizations and researchers. This chapter explores the reproductive toxicity of formaldehyde, one of the major components of the vapor of e-cigarettes.

MP45-16 PIOGLITAZONE MEDIATES IMPROVEMENT OF ERECTILE FUNCTION AFTER CAVERNOUS NERVE CRUSH INJURY VIA INSULIN GROWTH FACTOR TYPE 1

after surgery. The intracavernous pressure (ICP) and mean arterial pressure (MAP) was measured and midpenile cross-sections were histologically examined. Western blotting of cavernous tissue protein was performed. The data were analyzed using one-way analysis of variance followed by the Tukey-Kramer t test. RESULTS: Animals that received sildenafilþICA had significantly higher mean ICP/MAP ratio relative to all other rats with BCNI (p<0.05). The circumferenceandmeancross-sectional areaof thepaired corpus cavernosum were effectively preserved in the sildenafilþICA. In addition, the numbers of neuronal NO synthase (nNOS)-positive nerves andEdU-positive cells coexpressingS100 in the ICA-treatedgroupswere greater compared with the control group (p<0.05). CONCLUSIONS: The results indicate that ICA promotes endogenous SCs to differentiate into Schwann cells, which is essential for the regeneration of nNOS-positive nerves after BCNI; on this basis, sildenafil can then improve penile engorgement and prevent penile atrophy through the NO-derived smooth muscle relaxation. Therefore, the combinded use of ICA and daily sildenafil may be a candidate for the prevention and cure of neurogenic ED in the future.

Electronic Cigarettes: Toxicity and Addiction

1Department of Natural Sciences, Southern University at New Orleans, New Orleans, LA 70126, USA 2Department of Urology, Tulane University School of Medicine, New Orleans, LA 70112, USA *Corresponding author Bashir M. Rezk, PhD Associate Professor Department of Natural Sciences Southern University at New Orleans 6400 Press Drive New Orleans, LA 70126, USA Tel. +1(504)284-5405; +1(504)957-8806 E-mail: batteia@suno.edu

Chapter 59 – Developmental and Reproductive Disorders—Role of Endocrine Disruptors in Testicular Toxicity

Publisher Summary This chapter describes how a variety of extraneous and internal factors can induce developmental and testicular toxicity leading to teratogenesis, poor sperm quality and male factor infertility. Developmental and reproductive toxicologists and epidemiologists have identified and classified several environmental chemicals and pharmaceutical products including teratogens and endocrine disruptors that lead to developmental and reproductive disorders. Hence, it is extremely important to understand the role of such toxicants and environmental endocrine disruptors. Convincing evidence exists that chemical exposures may lead to increased estrogenic activity, reduced androgen levels, or otherwise interfere with the action of androgen during development, thus causing male reproductive system abnormalities. The severity of testicular damage is related to the category of chemotherapeutic agent used, the dose and duration of therapy, and the developmental stage of the testis. The recovery of spermatogenesis is variable and depends upon the total therapeutic dose and duration of treatment. In addition to endocrine-disruptor mechanisms, endocrine disruptors including pesticides, xenobiotics, heavy metals, radiations, smoking and alcohol generate free radicals that can induce developmental and reproductive abnormalities. Reactive oxygen species (ROS) can also induce oxidation of critical-SH groups in proteins and DNA, which will alter cellular integrity and function with an increased susceptibility to attack by toxicants. The hazard identification and dose–response data are developed from experimental animal studies that may be supplemented with data from in vitro studies. This information is then extrapolated and integrated to characterize and assess the risk to the human population.

Chapter 69 – Developmental and reproductive disorders: role of endocrine disruptors in testicular toxicity

Publisher Summary This chapter describes how a variety of extraneous and internal factors can induce developmental and testicular toxicity leading to teratogenesis, poor sperm quality and male factor infertility. Developmental and reproductive toxicologists and epidemiologists have identified and classified several environmental chemicals and pharmaceutical products including teratogens and endocrine disruptors that lead to developmental and reproductive disorders. Hence, it is extremely important to understand the role of such toxicants and environmental endocrine disruptors. Convincing evidence exists that chemical exposures may lead to increased estrogenic activity, reduced androgen levels, or otherwise interfere with the action of androgen during development, thus causing male reproductive system abnormalities. The severity of testicular damage is related to the category of chemotherapeutic agent used, the dose and duration of therapy, and the developmental stage of the testis. The recovery of spermatogenesis is variable and depends upon the total therapeutic dose and duration of treatment. In addition to endocrine-disruptor mechanisms, endocrine disruptors including pesticides, xenobiotics, heavy metals, radiations, smoking and alcohol generate free radicals that can induce developmental and reproductive abnormalities. Reactive oxygen species (ROS) can also induce oxidation of critical-SH groups in proteins and DNA, which will alter cellular integrity and function with an increased susceptibility to attack by toxicants. The hazard identification and dose–response data are developed from experimental animal studies that may be supplemented with data from in vitro studies. This information is then extrapolated and integrated to characterize and assess the risk to the human population.