Deregulation of ATG9A by impaired AR signaling induces autophagy in prostate stromal fibroblasts and promotes BPH progression

Activation of the cGMP/PKG/ERK signaling pathway associated with PDE5Is inhibits fibroblast activation by downregulating autophagy in early progressive benign prostatic hyperplasia

PURPOSE

Benign prostatic hyperplasia (BPH) is one of the most prevalent diseases affecting aging males. However, approximately, 8% of the BPH patients under 50-year-old experience remarkably early progression, for reasons that remain elusive. Among the various factors implicated in promoting BPH advancement, the activation of fibroblasts and autophagy hold particular importance. Our research endeavors to explore the mechanisms behind the accelerated progression in these patients.

METHODS

Immunohistochemistry and immunofluorescence were performed to detect the expression levels of LC3, p62, PDE5, and α-SMA in diverse BPH tissues and prostate stromal cells. The autophagy activator rapamycin, the autophagy suppressor chloroquine, and siRNA transfection were used to identify the impact of autophagy on fibroblast activation.

RESULTS

Prostatic stromal fibroblasts in early progressive BPH tissues displayed activation of autophagy with an upregulation of LC3 and a concurrent downregulation of p62. After starvation or rapamycin treatment to a heightened level of autophagy, fibroblasts exhibited activation. Conversely, chloroquine treatment and ATG-7-knockdown effectively suppressed the level of autophagy and fibroblast activation. High expression of PDE5 was found in early progressive BPH stromal cells. The administration of PDE5 inhibitors (PDE5Is) hindered fibroblast activation through suppressing autophagy by inhibiting the ERK signaling pathway.

CONCLUSION

Our findings suggest that autophagy plays a pivotal role in promoting BPH progression through fibroblast activation, while PDE5Is effectively suppress autophagy and fibroblast activation via the ERK signaling pathway. Nevertheless, further investigations are warranted to comprehensively elucidate the role of autophagy in BPH progression.

HCMV miR-UL70-3p downregulates the rapamycin-induced autophagy by targeting the autophagy-related protein 9A (ATG9A)

Human cytomegalovirus (HCMV) is a representative β-herpesvirus that establishes persistent infections in humans, and exhibits high seropositivity rates in adults. It has co-evolved with its human host and employs various strategies to evade antiviral mechanisms by utilizing a significant portion of its genome. HCMV-encoded proteins and miRNAs have been implicated in regulating these mechanisms, enabling viral survival within the human body. During viral infections, autophagy, a conserved catabolic process essential for cellular homeostasis, acts as an antiviral defense mechanism. Multiple studies have reported that HCMV can modulate autophagy through its proteins and miRNAs, thereby influencing its survival within the host. In this study, we showed the potential involvement of HCMV miRNAs in cellular autophagy. We employed various bioinformatic tools to predict putative HCMV miRNAs that target autophagy-related genes and their corresponding cellular autophagy genes. Our results show that the 3'UTR of autophagy-related genes, including ATG9A, ATG9B, ATG16L2, SQSTM1, and EIF2AK2, harbors potential binding sites for hcmv-miR-UL70-3p. Experimental manipulation involving ectopic expression of hcmv-miR-UL70-3p demonstrated a significant reduction in rapamycin-induced autophagy, with ATG9A as its functional target. These findings establish that hcmv-miR-UL70-3p acts as an autophagy inhibitor by suppressing the expression of ATG9A.

Exploring the Enigma of 5-ARIs Resistance in Benign Prostatic Hyperplasia: Paving the Path for Personalized Medicine

PURPOSE OF REVIEW

Despite the widespread utilization of 5-alpha reductase inhibitors (5-ARIs) for managing benign prostatic hyperplasia (BPH), certain BPH patients exhibit unresponsiveness to 5-ARIs therapy. This paper provides a comprehensive overview of the current perspectives on the mechanisms of 5-ARIs resistance in BPH patients and integrates potential biomarkers and underlying therapeutic options for 5-ARIs resistance. These findings may facilitate the development of novel or optimize more effective treatment options, and promote personalized medicine for BPH.

RECENT FINDINGS

The pathways contributing to resistance against 5-ARIs in certain BPH patients encompass epigenetic modifications, shifts in hormone levels, autophagic processes, and variations in androgen receptor structures, and these pathways may ultimately be attributed to inflammation. Promisingly, novel biomarkers, including intravesical prostatic protrusion, inflammatory factors, and single nucleotide polymorphisms, may offer predictive insights into the responsiveness to 5-ARIs therapy, empowering physicians to fine-tune treatment strategies. Additionally, on the horizon, GV1001 and mTOR inhibitors have emerged as potential alternative therapeutic modalities for addressing BPH in the future. After extensive investigation into BPH's pathological processes and molecular landscape, it is now recognized that diverse pathophysiological mechanisms may contribute to different BPH subtypes among individuals. This insight necessitates the adoption of personalized treatment strategies, moving beyond the prevailing one-size-fits-all paradigm centered around 5-ARIs. The imperative for early identification of individuals prone to treatment resistance will drive physicians to proactively stratify risk and adapt treatment tactics in future practice. This personalized medicine approach marks a progression from the current standard treatment model, emerging as the future trajectory in BPH management.

Hesperidin ameliorates benign prostatic hyperplasia by attenuating cell proliferation, inflammatory response, and epithelial-mesenchymal transition via the TGF-β1/Smad signaling pathway

Excessively activated transforming growth factor-beta 1 (TGF-β1) exacerbates benign prostatic hyperplasia (BPH) by triggering epithelial-mesenchymal transition (EMT) as well as epithelial and stromal cell differentiation. Hesperidin (HSP), a flavanone rich in citrus peels, exhibits a safe anti-cancer activity with few side effects. Although HSP reportedly inhibits cell growth in prostate cancer, studies on BPH have not yet been reported. Thus, this study aimed to figure out the therapeutic effect of HSP and its underlying mechanisms in BPH models in vivo and in vitro. To evaluate the anti-BPH effect of HSP in vivo, rats were injected with testosterone propionate (TP; 10 mg/kg, s.c.), finasteride (5 mg/kg, p.o.), and HSP (50 and 100 mg/kg, i.p.) for four weeks. The in vitro efficacy of HSP was evaluated using two prostate cell models, BPH-1 and dihydrotestosterone-stimulated WPMY-1 cells, for studying the interaction between epithelial and stromal cells. Both in vivo and in vitro, HSP inhibited prostate cell proliferation by suppressing the expression of androgen receptor-related markers. In addition, HSP reduced the expression levels of inflammatory and mesenchymal markers by blocking TGF-β1 activation. Collectively, HSP alleviated BPH by attenuating prostate cell proliferation, the inflammatory response, and EMT by regulating the TGF-β1/Smad signaling pathway. Thus, these results provide evidence for a new therapeutic approach against BPH.

Decreased mitophagy aggravates benign prostatic hyperplasia in aged mice through DRP1 and estrogen receptor α

Benign prostatic hyperplasia (BPH) is an age-related disease, whose etiology largely remains unclear. The regulation of mitophagy plays a key role in aging and associated diseases, however, its function in BPH has not been studied. Although the expression of the androgen receptor is primarily implicated in BPH, the estrogen receptor (ER) has been reported to be involved in the development of BPH by mediating the proliferation of prostate cells. Here, we studied the involvement of mitophagy and ERs in spontaneous BPH in aging mice and investigated their functions. To identify the activation of mitophagy and expression of ERs, 8-week, 12-month, and 24-month-old mice were used. Mice were treated with mitochondrial division inhibitor mdivi-1, a dynamin-related protein 1 (Drp1) inhibitor, to examine the expression of mitophagy-related proteins and the development of BPH. In addition, prostate stromal cells were treated with an ER antagonist to investigate the regulation of mitophagy following the expression of ERs. With aging, the Drp1 and phosphorylation of parkin reduce. Electron microscopy revealed reduced mitochondrial fission and mitophagy. In addition, the expression of androgen receptor was decreased and that of ERα was increased in aged mice with BPH. Treatment with mdivi-1 exacerbated BPH and increased cell proliferation. In addition, blockade of ERα increased mitophagy and decreased cell proliferation. In conclusion, mitophagy is reduced with aging during the development of BPH. We speculate that spontaneous BPH progresses through the reduction in the expression of ERα in aged mice by downregulating mitophagy.

Silencing of LLGL2 Suppresses the Estradiol-Induced BPH-1 Cell Proliferation through the Regulation of Autophagy

Lethal giant larvae (Lgl) is an apical-basal polarity gene first identified in Drosophila. LLGL2 is one of the mammalian homologs of Lgl. However, little is known about its function in the prostate. In this study, to explore the new role of LLGL2 in the prostate, we examined the proliferative activity of a BPH-1 cell line, a well-established model for the human prostate biology of benign prostatic hyperplasia (BPH). The expression of LLGL2 was dose-dependently increased in BPH-1 cells after treatment with 17β-estradiol (E2). Additionally, E2 treatment increased the proliferation of the BPH-1 cells. However, the knockdown of LLGL2 with siRNA significantly suppressed the proliferation of the E2-treated BPH-1 cells. Moreover, si-llgl2 treatment up-regulated the expression of LC-3B, ATG7, and p-beclin, which are known to play a pivotal role in autophagosome formation in E2-treated BPH-1 cells. Overexpression of LLGL2 was able to further prove these findings by showing the opposite results from the knockdown of LLGL2 in E2-treated BPH-1 cells. Collectively, our results suggest that LLGL2 is closely involved in the proliferation of prostate cells by regulating autophagosome formation. These results provide a better understanding of the mechanism involved in the effect of LLGL2 on prostate cell proliferation. LLGL2 might serve as a potential target in the diagnosis and/or treatment of human BPH.

Rauwolfia vomitoria extract suppresses benign prostatic hyperplasia by inducing autophagic apoptosis through endoplasmic reticulum stress

Background

The current drug treatments for benign prostatic hyperplasia (BPH) have negative side effects. Therefore, it is important to find effective alternative therapies with significantly fewer side effects. Our previous study revealed that Rauwolfia vomitoria (RWF) root bark extract reversed BPH development in a rat model. However, the molecular mechanism of its inhibitory effects on BPH remains largely unknown.

Methods

BPH-1 and WPMY-1 cell lines derived from BPH epithelial and prostatic stromal compartments were selected to investigate how RWF extract inhibits BPH in vitro by MTT and flow cytometry assays. Microarray, quantitative real-time PCR, immunoblotting, and GFP-LC3 immunofluorescence assays were performed to evaluate the effects of RWF extract on endoplasmic reticulum stress (ER stress) and autophagic apoptosis pathways in two cell lines. A human BPH ex vivo explant assay was also employed for validation.

Results

RWF extract treatment decreased cell viability and induced apoptotic cell death in both BPH-1 and WPMY-1 cells in a concentration-dependent manner with the increase of pro-apoptotic PCDC4 protein. RWF extract induced autophagy by enhancing the levels of autophagic genes (ULK2 and SQSTM1/p62) and the LC3II:LC3I ratio, with the increase of GFP-LC3 puncta. Moreover, RWF extract activated PERK- and ATF6-associated ER stress pathways by inducing the transcriptional levels of EIF2AK3/PERK, DDIT3/CHOP and ATF6, accompanied by the reduction of BiP protein level, but not its mRNA level. Another ER stress pathway was not induced by RWF extract, as manifested by the lack of XBP1 splicing. Pharmacological inhibition of autophagy by 3-methyladenine abrogated apoptosis but not ER stress; while inhibition of ER stress by 4-phenylbutyrate alleviated the induction of autophagy and apoptosis. In addition, pretreatments with either 3-methyladenine or 4-phenylbutyrate suppressed RWF extract-induced cytotoxicity. Notably, the inductions of PERK- and ATF6-related stress pathways and autophagic apoptosis were confirmed in a human BPH ex vivo explant.

Conclusions

Our data have demonstrated that RWF extract significantly suppressed the viabilities of BPH epithelial cells and BPH myofibroblasts by inducing apoptosis via upregulating ER stress and autophagy. These data indicate that RWF extract is a potential novel alternative therapeutic approach for BPH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03610-4.

YiQiFuMai lyophilized injection attenuates cerebral ischemic injury with inhibition of neuronal autophagy through intervention in the NMMHC IIA-actin-ATG9A interaction

BACKGROUND

YiQiFuMai lyophilized injection (YQFM) is derived from a traditional Chinese medicine prescription termed Shengmai San.YQFM is clinically applied to the treatment of cardiovascular and cerebrovascular diseases. It has been found that critical components of YQFM affect non-muscle myosin heavy chain IIA (NMMHC IIA), but its regulation in the excessive autophagy and the underlying mechanism has yet to be clarified.

PURPOSE

To evaluate whether YQFM has neuroprotective effects on cerebral ischemia/reperfusion-induced injury by inhibiting NMMHC IIA-actin-ATG9A interaction for autophagosome formation.

METHODS

The neuroprotective effects of YQFM were investigated in vivo in mice with middle cerebral artery occlusion/reperfusion (MCAO/R) (n = 6) by detecting neurological deficits, infarct volume, and histopathological changes. The NMMHC IIA-actin-ATG9A interaction was determined using immunofluorescence co-localization, co-immunoprecipitation, and proximity ligation assay. Rat pheochromocytoma (PC12) cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) were used to mimic neurons in in vitro experiments.

RESULTS

In MCAO/R model mice, YQFM (1.342 g/kg) attenuated brain ischemia/reperfusion-induced injury by regulating NMMHC IIA-actin-mediated ATG9A trafficking. YQFM (400 μg/ml) also exerted similar effects on OGD/R-induced PC12 cells. Furthermore, RNAi of NMMHC IIA weakened the NMMHC IIA-F-actin-dependent ATG9A trafficking and, therefore, attenuated the neuroprotective activities of YQFM in vitro.

CONCLUSION

These findings demonstrated that YQFM exerted neuroprotective effects by regulating the NMMHC IIA-actin-ATG9A interaction for autophagosome formation. This evidence sheds new light on the potential mechanism of YQFM in the treatment of cerebral ischemia/reperfusion.

LMO2 upregulation due to AR deactivation in cancer-associated fibroblasts induces non-cell-autonomous growth of prostate cancer after androgen deprivation

The androgen receptor (AR) is expressed in prostate fibroblasts in addition to normal prostate epithelial cells and prostate cancer (PCa) cells. Moreover, AR activation in fibroblasts dramatically influences prostate cancer (PCa) cell behavior. Androgen deprivation leads to deregulation of AR downstream target genes in both fibroblasts and PCa cells. Here, we identified LIM domain only 2 (LMO2) as an AR target gene in prostate fibroblasts using ChIP-seq and revealed that LMO2 can be repressed directly by AR through binding to androgen response elements (AREs), which results in LMO2 overexpression after AR deactivation due to normal prostate fibroblasts to cancer-associated fibroblasts (CAFs) transformation or androgen deprivation therapy. Next, we investigated the mechanisms of LMO2 overexpression in fibroblasts and the role of this event in non-cell-autonomous promotion of PCa cells growth in the androgen-independent manner through paracrine release of IL-11 and FGF-9. Collectively, our data suggest that AR deactivation deregulates LMO2 expression in prostate fibroblasts, which induces castration resistance in PCa cells non-cell-autonomously through IL-11 and FGF-9.

DNA methyltransferase-1 inactivation of androgen receptor axis triggers homocysteine induced cardiac fibroblast autophagy in diabetic cardiac fibrosis

Diabetic cardiac fibrosis is one of the main pathological manifestations of diabetic cardiomyopathy (DCM). Cardiac fibroblast autophagy plays critical roles in diabetic cardiac fibrosis, however, the underlying mechanism of cardiac fibroblast autophagy and diabetic cardiac fibrosis still largely unknown. The aim of the study was to investigate the mechanism of DNMT1 mediated DNA methylation alterations control cardiac fibroblast autophagy in diabetic cardiac fibrosis. We employed streptozotocin (STZ)-induced rats DCM, DCM patient and Hcy induced cardiac fibroblast autophagy. Heart tissue sections were stained with H&E, Sirius Red and Masson's trichrome stain. The expression of DNMT1, AR, Collagen genes mRNA was detected by qRT-PCR. MSP and BSP detected the methylation status of the AR promoter. The expression of DNMT1, AR, Collagen and autophagy-related proteins were detected by Western blotting, Immunofluorescence, Immunohistochemistry. Gain and loss function of AR and DNMT1 in cardiac fibroblast was analyzed. DNMT1 inhibition or knockdown elevated the expression of AR in cardiac fibroblast. Furthermore, we found that AR negatively regulation of Hcy induced cardiac fibroblast autophagy. We demonstrated that DNMT1 enhances cardiac fibroblast autophagy in diabetic cardiac fibrosis through inhibiting AR axis. In conclusion, our results provide new insight into the DNMT1 inactivation of AR axis triggers cardiac fibroblast autophagy in diabetic cardiac fibrosis.

Autophagy regulates lipid production and contributes to the sebosuppressive effect of retinoic acid in human SZ95 sebocytes

BACKGROUND

Autophagy is a catabolic process for eliminating damaged organelles or proteins to maintain cellular homeostasis. Recently, lipids have been demonstrated to be targets for autophagosomal degradation. Therefore, autophagy might be involved in sebaceous gland homeostasis, however, relevant data are lacking.

OBJECTIVES

We investigated the role of autophagy in sebaceous lipogenesis and its regulatory mechanisms in human SZ95 sebocytes. We also examined the possible role of autophagy in 13-cis-retinoic acid (13-cis-RA)-mediated sebosuppression.

METHODS

Autophagy markers expression was examined by immunohistochemistry in normal and acne lesional skin. SZ95 sebocytes were treated with autophagy inhibitors under starvation or treated with a combination of testosterone and linoleic acid (testosterone/LA), with or without autophagy inducer rapamycin or 13-cis-RA. Lipids were assessed by BODIPY and quantitative Nile Red staining. Autophagy-related gene 7 small interference RNA was used to confirm the role of autophagy on the sebosuppressive effect of rapamycin or 13-cis-RA.

RESULTS

Autophagy markers were strongly expressed in the maturing sebaceous gland cells in healthy skin, whereas downregulated in the acne-involved sebaceous glands. Testosterone/LA or insulin-like growth factor-1 inhibited starvation-induced sebocyte autophagy. Pharmacological inhibition of autophagy led to increased sebaceous lipid accumulation. Contrary, rapamycin inhibited the testosterone/LA-induced lipogenesis and expression of fatty acid synthesis genes via activating the autophagy pathway. 13-cis-RA increased autophagy in SZ95 sebocytes, partly via FoxO1 activation, and inhibition of autophagy abolished the sebosuppressive effect of 13-cis-RA.

CONCLUSIONS

Autophagy plays an important role in the modulation of lipogenesis in human sebocytes and is involved in the sebostatic effect of 13-cis-RA.

5-ARI induces autophagy of prostate epithelial cells through suppressing IGF-1 expression in prostate fibroblasts

Objectives

5α‐reductase inhibitor (5‐ARI) is a commonly used medicine in the treatment of lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). Our study mainly focuses on the mechanism of BPH development after 5ARI treatment.

Materials and Methods

Prostate specimens from patients were collected. Insulin‐like growth factor 1 (IGF‐1), Beclin‐1, LC3 levels, was analysed by immunohistochemistry. The role IGF‐1 on autophagic flux in prostate epithelial cells was studied. Additionally, effect of autophagy on recombinant grafts consisting of prostate stromal and epithelial cells in nude mice was investigated.

Results

We demonstrated that IGF‐1 expression is down‐regulated in prostate fibroblasts after long‐term 5‐ARI application. A decrease in IGF‐1 levels was found to activate autophagic flux through the mTOR pathway in prostate epithelial cells, while the inhibition of IGF‐1 receptor function induced autophagy in prostate epithelial cells. In addition, we revealed that blocking autophagic flux initiation can reduce the volume of recombinant grafts in vivo. Finally, our findings suggest that long‐term 5‐ARI application reduces IGF‐1 secretion by prostatic stromal cells, thereby inducing autophagy of prostatic epithelial cells, which is one of the mechanisms underlying BPH pathogenesis and progression.

Conclusions

Focusing on the autophagy induced by low levels of IGF‐1 in prostatic epithelial cells, after elucidating AR signalling impairment of prostate stromal cells, might provide a novel strategy for the treatment and prevention of BPH development.