Desquamation is a novel phenomenon for collective prostate epithelial cell deletion after castration

Prolactin promotes a partial recovery from the atrophy of both male and female gerbil prostates caused by castration

BACKGROUND

The male and female prostates are controlled by steroid hormones, suffering important morphological and physiological changes after castration. Prolactin is involved in the regulation of the male prostate, having already been identified in the tissue, acting through its receptor PRLR. In the Mongolian gerbil, in addition to the male prostate, the female prostate is also well developed and active in its secretion processes. The aim of the present study was to evaluate the effects of exposure to exogenous prolactin in the prostate of both intact and castrated male and female gerbils in order to establish if prolactin administration can sustain prostate cell activity in conditions of sexual hormone deprivation.

METHODS

The morphological analyses were performed by biometric analysis, lesion histological analysis and morphometric-stereological aspects. In addition, immune-cytochemical tests were performed for prolactin and its receptor, as well as for the receptors of androgen and oestrogen and serum prolactin dosage. All data were submitted to ANOVA or Kruskal-Wallis tests for comparison between groups. P < 0.05 was considered to be statistically significant.

RESULTS

The results showed a strong influence of prolactin on the morphology of the prostate, with the development of important epithelial alterations, after only 3 days of administration, and an expressive epithelial cell discard process after 30 days of administration. Prolactin acts in synergy with testosterone in males and mainly with oestrogens in females, establishing different steroid hormonal receptor immunoreactivity according to sex. It was also demonstrated that prolactin can assist in the recovery from some atrophic effects caused in the gland after castration, without causing additional tissue damage.

CONCLUSIONS

The prolactin and its receptor are involved in the maintenance of the homeostasis of male and female gerbils, and also cause distinct histological alterations after exogenous exposure for 3 and 30 days. The effects of prolactin are related to its joint action on androgens and oestrogens and it can also assist in the recovery from the atrophic effects of castration.

Melatonin ameliorates degenerative alterations caused by age in the rat prostate and mitigates high-fat diet damages

Imbalance of sexual steroids milieu and oxidative stress are often observed during aging and correlated to prostate disorders. Likewise, high-fat intake has been related to prostate damage and tumor development. Melatonin (MLT) is an antioxidant whose secretion decreases in elderly and is also suggested to protect the gland. This study evaluated the impact of a long-term high-fat diet during aging on prostate morphology and antioxidant system of rats and tested the effects of MLT supplementation under these conditions. Male rats were assigned into four groups: control, treated with MLT, high-fat diet and high-fat diet treated with MLT. The high-fat diet was provided from the 24th week of age, MLT from the 48th (100 μg/kg/day) and rats were euthanized at the 62nd week. The high-fat diet increased body weight, retroperitoneal fatness, glycaemia, and circulating estrogen levels. It aggravated the aging effects, leading to epithelial atrophy (∼32% reduction of epithelial height) and collagen fibers increase (83%). MLT alone did not alter biometric and physiological parameters, except for the prostate weight decrease, whereas it alleviated biometric as well as ameliorated acinar atrophy induced by high-lipid intake. Systemic oxidative stress increased, and prostatic glutathione peroxidase activity decreased fivefold with the high-fat diet despite the indole. Regardless of the diet, MLT triggered epithelial desquamation, reduced androgen receptor-positive cells, increased smooth muscle layer thickness (12%), decreased at least 50% corpora amylacea formation, and stimulated prostatic gluthatione-S-transferase activity. In conclusion, MLT partially recovered prostate damage induced by aging and the long-term high-fat diet and ameliorated degenerative prostate alterations.

Transcriptional regulators and regulatory pathways involved in prostate gland adaptation to a hypoandrogen environment

Anti-androgen therapies, including orchiectomy, are effective at promoting prostate cancer remission, but are followed by progression to the more aggressive castration-resistant prostate cancer (CRPC). Castration promotes gland and tumor shrinkage. However, prostate adaptation to androgen deprivation involves striking parallel events, all requiring changes in gene expression. We hypothesized that transcription factors (TF) and other transcription-related genes are needed to orchestrate those changes. In this work, downstream analysis using bioinformatic tools and published microarray data allowed us to identify sixty transcriptional regulators (including 10 TF) and to integrate their function in physiologically relevant networks. Functional associations revealed a connection between Arnt, Bhlhe41 and Dbp circadian rhythm genes with the Ar circuitry and a small gene network centered in Pex14, which might indicate a previously unanticipated metabolic shift. We have also identified human homologs and mapped the corresponding genes to human chromosome regions commonly affected in prostate cancer, with particular attention to the PTEN/HHEX/MXI1 cluster at 10q23-25 (frequently deleted in PCa) and to MAPK1 at 22q11.21 (delete in intermediate risk but not in high risk PCa). Twenty genes were found mutated or with copy number alterations in at least five percent of three cancer cohorts and six of them (PHOX2A, NFYC, EST2, EIF2S1, SSRP1 and PARP1) associated with impacted patient survival. These changes are specific to the adaptation to the hypoandrogen environment and seem important for the progression to CRPC when mutated.

Hyaluronan content and distribution in the rat ventral prostate after castration

Hyaluronan (HA) has been implicated in tissue remodeling, healing, and tumor growth. This study investigated the variation in hyaluronan content, distribution, and metabolism in the rat ventral prostate (VP) in response to androgen deprivation after castration. The mRNA abundance of hyaluronan synthases (Has1-3) and hyaluronidases (Hyal 1-3) were assessed by reverse transcription (RT)-PCR and immunohistochemistry, respectively. The results demonstrated an increased concentration, but an overall reduction in HA content. HA was located in both epithelium and stroma of the prostate of both the noncastrated and castrated animals. Quantitative RT-PCR (qRT-PCR) showed that Has1 and Has2 are major synthases, and that Hyal 1 was the predominant hydrolase expressed in the VP. qRT-PCR also showed that Has1 and Has2 mRNA increased transiently after castration, whereas Has3 mRNA declined markedly. While Hyal 1 mRNA increased slowly up to day 21 after castration, Hyal 2 and Hyal 3 mRNA dropped significantly. CD44 was found in the epithelial cells and in some stromal cells in both hormonal conditions. In conclusion, castration results in increased abundance of Has1 and Has2 mRNA, but is associated with a decrease in the total content of HA, with an increased concentration, and a predominance of short-chain HA molecules.

Macrophage roles in the clearance of apoptotic cells and control of inflammation in the prostate gland after castration

BACKGROUND

Androgen deprivation results in massive apoptosis in the prostate gland. Macrophages are actively engaged in phagocytosing epithelial cell corpses. However, it is unknown whether microtubule-associated protein 1 light chain 3 alpha (LC3)-associated phagocytosis (LAP) is involved and contribute to prevent inflammation.

METHODS

Flow cytometry, RT-PCR and immunohistochemistry were used to characterize the macrophage subpopulation residing in the epithelial layer of the rat ventral prostate (VP) after castration. Stereology was employed to determine variations in the number of ED1 and ED2. Mice were treated with either chloroquine or L-asparagine to block autophagy.

RESULTS

M1 (iNOS-positive) and M2 macrophages (MRC1+ and ARG1+) were not found in the epithelium at day 5 after castration. The percentage of CD68⁺ (ED1) and CD163⁺ (ED2) phenotypes increased after castration but only CD68⁺ cells were present in the epithelium. RT-PCR showed increased content of the autophagy markers Bcl1 and LC3 after castration. In addition, immunohistochemistry showed the presence of LC3⁺ and ATG5⁺ cells in the epithelium. Double immunohistochemistry showed these cells to be CD68⁺ /LC3⁺ , compatible with the LAP phenotype. LC3⁺ cells accumulate significantly after castration. Chloroquine and L-asparagine administration caused inflammation of the glands at day 5 after castration.

CONCLUSIONS

CD68⁺ macrophages phagocytose apoptotic cell corpses and activate the LAP pathway, thereby contributing to the preservation of a non-inflammed microenvironment. Marked inflammation was detected when autophagy blockers were administered to castrated animals.

Desquamation takes center stage at the origin of proliferative inflammatory atrophy, epithelial-mesenchymal transition, and stromal growth in benign prostate hyperplasia

In this commentary, we propose a relationship between desquamation, initially described as the collective detachment and deletion of epithelial cell in the prostate gland after castration, and proliferative inflammatory atrophy (PIA) and stromal growth in benign prostate hyperplasia (BPH). First, in response to diverse stimuli, including inflammatory mediators, epithelial cells desquamate and leave a large surface of the luminal side of the basement membrane (BM) exposed. Basal cells are activated into intermediate-type cells, which change morphology to cover and remodel the exposed BM (simple atrophy) to a new physiological demand (such as in the hypoandrogen environment, simulated by surgical and/or chemical castration) and/or to support re-epithelialization (under normal androgen levels). In the presence of inflammation (that might be the cause of desquamation), the intermediate-type cells proliferate and characterize PIA. Second, in other circumstances, desquamation is an early step of epithelial-to-mesenchymal transition (EMT), which contributes to stromal growth, as suggested by some experimental models of BPH. The proposed associations correlate unexplored cell behaviors and reveal the remarkable plasticity of the prostate epithelium that might be at the origin of prostate diseases.

Osteoarthritis in the XXIst century: risk factors and behaviours that influence disease onset and progression

Osteoarthritis (OA) is a growing public health problem across the globe, affecting more than half of the over 65 population. In the past, OA was considered a wear and tear disease, leading to the loss of articular cartilage and joint disability. Nowadays, thanks to advancements in molecular biology, OA is believed to be a very complex multifactorial disease. OA is a degenerative disease characterized by “low-grade inflammation” in cartilage and synovium, resulting in the loss of joint structure and progressive deterioration of cartilage. Although the disease can be dependent on genetic and epigenetic factors, sex, ethnicity, and age (cellular senescence, apoptosis and lubricin), it is also associated with obesity and overweight, dietary factors, sedentary lifestyle and sport injuries. The aim of this review is to highlight how certain behaviors, habits and lifestyles may be involved in the onset and progression of OA and to summarize the principal risk factors involved in the development of this complicated joint disorder.

Ameliorative effects of PACAP against cartilage degeneration. Morphological, immunohistochemical and biochemical evidence from in vivo and in vitro models of rat osteoarthritis

Osteoarthritis (OA); the most common form of degenerative joint disease, is associated with variations in pro-inflammatory growth factor levels, inflammation and hypocellularity resulting from chondrocyte apoptosis. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide endowed with a range of trophic effects in several cell types; including chondrocytes. However; its role in OA has not been studied. To address this issue, we investigated whether PACAP expression is affected in OA cartilage obtained from experimentally-induced OA rat models, and then studied the effects of PACAP in isolated chondrocytes exposed to IL-1β in vitro to mimic the inflammatory milieu of OA cartilage. OA induction was established by histomorphometric and histochemical analyses. Changes in PACAP distribution in cartilage, or its concentration in synovial fluid (SF), were assessed by immunohistochemistry and ELISA. Results showed that PACAP abundance in cartilage tissue and SF was high in healthy controls. OA induction decreased PACAP levels both in affected cartilage and SF. Invitro, PACAP prevented IL-1β-induced chondrocyte apoptosis, as determined by MTT assay; Hoechst staining and western blots of apoptotic-related proteins. These changes were also accompanied by decreased i-NOS and COX-2 levels, suggesting an anti-inflammatory effect. Altogether, these findings support a potential role for PACAP as a chondroprotective agent for the treatment of OA.

The Histochemistry and Cell Biology pandect: the year 2014 in review

This review encompasses a brief synopsis of the articles published in 2014 in Histochemistry and Cell Biology. Out of the total of 12 issues published in 2014, two special issues were devoted to "Single-Molecule Super-Resolution Microscopy." The present review is divided into 11 categories, providing an easy format for readers to quickly peruse topics of particular interest to them.