Rapamycin Alleviates Hormone Imbalance-Induced Chronic Nonbacterial Inflammation in Rat Prostate Through Activating Autophagy via the mTOR/ULK1/ATG13 Signaling Pathway

The causative effect of CXCR7 on experimental autoimmune prostatitis injury and fibrosis

Chronic prostatitis and Pelvic Pain syndrome (CP/CPPS) is an autoimmune inflammatory disease characterized by pelvic or perineal pain and infiltration of inflammatory cells in the prostate. C-X-C chemokine receptor type 7 (CXCR7) is an atypical chemokine receptor that has been shown to play a key role in inflammatory processes in prostate cancer. However, the role of CXCR7 in autoimmune prostate and immune regulation in CP/CPPS along with the mechanism of action for CXCR7 remains unclear. In this study, a mouse model of experimental autoimmune prostatitis (EAP) was constructed by subcutaneous injection of antigen, and CXCR7 agonist was administered to investigate the effects of CXCR7 on the proportion of immune cells and fibrosis in CP/CPPS. Western blotting, immunohistochemical staining and immunofluorescence, flow cytometry, and masson's trichrome staining were used to study the regulatory mechanisms of CXCR7 in immune regulation. CXCR7 agonists can significantly reduce pain and prostatic inflammation, and in vivo flow cytometry studies showed that the antagonists restored the imbalance of the Th17/Treg cell ratio. To elucidate the potential mechanisms by which CXCR7 influences the pathogenesis of CP/CPPS, we conducted simultaneous RNA-seq and non-targeted metabolome sequencing. Our findings suggest that CXCR7 agonists alleviate fibrosis in autoimmune prostatitis by inhibiting the TGFβ/SMAD pathway. This study provides the foundation to target the immunological function of CXCR7 as a novel therapy for CP/CPPS.

AP-1 activates KCNN4-mediated Ca2+ signaling to induce the Th1/Th17 differentiation of CD4+ cells in chronic non-bacterial prostatitis

The intraprostatic inflammatory infiltrate is characterized by Th1 CD4+ T cells, and its molecular mechanism is not well defined. This study explored the mechanisms responsible for the alteration of Th1/Th17 differentiation of CD4+ T cells in chronic non-bacterial prostatitis (CNP). CNP rats were induced by the administration of testosterone and 17β-estradiol. The Th1/Th17 cell percentage was increased in the prostate tissue of CNP rats, which was accompanied by increased IL-2, IFN-γ, IL-17A, and IL-22 levels. Transcriptome sequencing was performed, followed by KEGG pathway enrichment analysis. Activator protein-1 (AP-1) was enhanced in CD4+ T cells from CNP rats, and its inhibitor SR11302 suppressed Th1/Th17 differentiation and delayed CNP. AP-1 transcriptionally activated the expression of KCNN4, which potentiated mTORC1 in CD4+ T cells by enhancing Ca2+ signaling, thereby promoting Th1/Th17 differentiation. Rapamycin-mediated autophagy activation reversed AP-1/KCNN4/mTORC1-promoted Th1/Th17 differentiation, thereby inhibiting CNP. These results suggest that AP-1-mediated KCNN4 transcription promotes the inhibition of autophagy by mTORC1 through Ca2+ signaling, which supports Th1/Th17 differentiation of CD4+ T cells, resulting in the transformation of CNP to prostatic intraepithelial neoplasia and adenocarcinoma.

The role of autophagy in prostate cancer and prostatic diseases: a new therapeutic strategy

BACKGROUND

Autophagy is a well-conserved catabolic process that plays a key role in cell homeostasis. In the prostate, defective autophagy has been implicated in the genesis and progression of several pathological conditions.

AIM

The present review explored the autophagy pathway in prostate-related dysfunctions, focusing on prostate cancer (PCa), benign prostatic hyperplasia (BPH) and prostatitis.

RESULTS

Impaired autophagy activity has been shown in animal models of BPH and prostatitis. Moreover, autophagy activation by specific and non-specific drugs improved both conditions in pre-clinical studies. Conversely, the efficacy of autophagy inducers in PCa remains controversial, depending on intrinsic PCa characteristics and stage of progression. Intriguingly, autophagy inhibitors have shown beneficial effects in PCa suppression or even to overcome chemotherapy resistance. However, there are still open questions regarding the upstream mechanisms by which autophagy is deregulated in the prostate and the exact role of autophagy in PCa. The lack of specificity and increased toxicity associated with the currently autophagy inhibitors limits its use clinically, reflecting in reduced number of clinical data.

CONCLUSION

New therapeutic strategies to treat prostatic diseases involving new autophagy modulators, combination therapy and new drug formulations should be explored. Understanding the autophagy signaling in each prostatic disease is crucial to determine the best pharmacological approach.

Deciphering anti-benign prostatic hyperplasia potential of liangwanoside II based on metabolite profile characterization combined with targeted network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Metapanax delavayi (Franch.) J.Wen & Frodin (Araliaceae), known as "liang wang cha" in China, has been used to treat prostatitis as herbal tea in folk. Recent research suggested that aqueous extract of Metapanax delavayi leaf showed an advantage in anti-benign prostate hyperplasia (BPH) activity, and liangwanoside II was the main component of the active fraction. However, the anti-BPH effect of liangwanosdie II remains to be revealed.

AIM OF THE STUDY

This study aims to decipher anti-benign prostatic hyperplasia potential of liangwanoside II.

MATERIALS AND METHODS

The anti-BPH effect was evaluated by testosterone propionate-induced BPH rats after oral administration of liangwanoside II at the doses of 30, 60 and 120 mg/kg in vivo. Then, the metabolites of liangwanoside II in BPH rats in vivo were identified using ultra-performance liquid chromatography coupled with quadrupole tandem time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Finally, the targeted network pharmacology combined with experimental verification were explored for the mechanism elucidation.

RESULTS

Liangwanoside II exhibited an anti-BPH effect through reducing the weight of the prostate, prostate index and serum prostatic acid phosphatase level, and improving the prostate tissue morphology in BPH rats. Further, 16 metabolites of liangwanoside II in vivo were identified by UPLC-Q-TOF-MS analysis, in which the prototype compound and 4 metabolites, such as liangwanoside I and serratagenic acid could be absorbed in the plasma and then penetrate the blood-prostate barrier. Then, followed by the targeted network pharmacology and experimental verification, we found that liangwanoside II and its metabolites could jointly involve in the inhibition of the inflammation reaction and hormone imbalance, thus reducing oxidative stress damage, and restoring the balance between cell proliferation and apoptosis, which contributed to the anti-BPH effect of liangwanoside II.

CONCLUSION

The anti-BPH potential of liangwanoside II was revealed using metabolite profile characterization combined with targeted network pharmacology, providing new insight into the development and utilization of liangwanoside II.

Beclin1- and Atg13-dependent autophagy activation and morroniside have synergistic effect on osteoblastogenesis

Morroniside is known to improve osteoporosis by promoting osteoblastogenesis. The activation of PI3K/Akt/mTOR signaling is a significant mechanism in morroniside-promoted osteoblastogenesis. It is well known that protective autophagy is an important factor in osteoblastogenesis. However, the activation of mTOR signaling can inhibit autophagy. This study aimed to investigate the relationship between mTOR signaling and autophagy in morroniside-regulated osteoblastogenesis. In this study, we investigated the effect of morroniside on the autophagic activity (LC3 conversion rate, LC3-puncta formation, and autophagosome number) of differentiated osteoblast precursors (MC3T3-E1 cells). Then, we identified the roles of mTOR knockdown in morroniside-regulated alterations of autophagy and osteogenic parameters in MC3T3-E1 cells. Next, mTOR knockdown and overexpression were used to observe the roles of mTOR in morroniside-regulated alterations of autophagic molecules (Atg7, Atg13, and Beclin1). Subsequently, the additional value of the above autophagic molecules on morroniside-regulated osteogenic parameters in MC3T3-E1 cells was analyzed based on lentiviral transduction. Finally, combined with morroniside and TAT-Beclin1, the roles of Beclin1 upregulation in the in vivo effects of morroniside was investigated. Our experimental data showed that morroniside promoted both the mTOR activity and autophagy in MC3T3-E1 cells. Morroniside-upregulated autophagic activity and Atg13 or Beclin1 protein level in MC3T3-E1 cells were enhanced by mTOR knockdown. Furthermore, Morroniside-upregulated Atg13 and Beclin1 expression was reversed by mTOR overexpression. Importantly, autophagy upregulation with overexpression of the autophagic gene, Atg13 or BECN1 (gene form of Beclin1), significantly promoted osteoblastogenesis regulated by morroniside. The promotional effect of morroniside on bone microarchitecture, bone mass, and bone parameters (including trabecular bone area and OCN expression in trabecular bone) in ovariectomized (OVX) mice was enhanced by TAT-Beclin1 administration. In conclusion, the autophagy-enhancing drugs related to Beclin1 or Atg13 may be an effective adjuvant therapy in the treatment of osteoporosis with morroniside.

Autophagy and beyond: Unraveling the complexity of UNC-51-like kinase 1 (ULK1) from biological functions to therapeutic implications

UNC-51-like kinase 1 (ULK1), as a serine/threonine kinase, is an autophagic initiator in mammals and a homologous protein of autophagy related protein (Atg) 1 in yeast and of UNC-51 in Caenorhabditis elegans. ULK1 is well-known for autophagy activation, which is evolutionarily conserved in protein transport and indispensable to maintain cell homeostasis. As the direct target of energy and nutrition-sensing kinase, ULK1 may contribute to the distribution and utilization of cellular resources in response to metabolism and is closely associated with multiple pathophysiological processes. Moreover, ULK1 has been widely reported to play a crucial role in human diseases, including cancer, neurodegenerative diseases, cardiovascular disease, and infections, and subsequently targeted small-molecule inhibitors or activators are also demonstrated. Interestingly, the non-autophagy function of ULK1 has been emerging, indicating that non-autophagy-relevant ULK1 signaling network is also linked with diseases under some specific contexts. Therefore, in this review, we summarized the structure and functions of ULK1 as an autophagic initiator, with a focus on some new approaches, and further elucidated the key roles of ULK1 in autophagy and non-autophagy. Additionally, we also discussed the relationships between ULK1 and human diseases, as well as illustrated a rapid progress for better understanding of the discovery of more candidate small-molecule drugs targeting ULK1, which will provide a clue on novel ULK1-targeted therapeutics in the future.

Mammalian Target of Rapamycin as the Therapeutic Target of Vascular Proliferative Diseases: Past, Present, and Future

ABSTRACT

The abnormal proliferation of vascular smooth muscle cells (VSMCs) is a key pathological characteristic of vascular proliferative diseases. Mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that plays an important role in regulating cell growth, motility, proliferation, and survival, as well as gene expression in response to hypoxia, growth factors, and nutrients. Increasing evidence shows that mTOR also regulates VSMC proliferation in vascular proliferative diseases and that mTOR inhibitors, such as rapamycin, effectively restrain VSMC proliferation. However, the molecular mechanisms linking mTOR to vascular proliferative diseases remain elusive. In our review, we summarize the key roles of the mTOR and the recent discoveries in vascular proliferative diseases, focusing on the therapeutic potential of mTOR inhibitors to target the mTOR signaling pathway for the treatment of vascular proliferative diseases. In this study, we discuss mTOR inhibitors as promising candidates to prevent VSMC-associated vascular proliferative diseases.

Impacts of Immunometabolism on Male Reproduction

The physiological process of male reproduction relies on the orchestration of neuroendocrine, immune, and energy metabolism. Spermatogenesis is controlled by the hypothalamic-pituitary-testicular (HPT) axis, which modulates the production of gonadal steroid hormones in the testes. The immune cells and cytokines in testes provide a protective microenvironment for the development and maturation of germ cells. The metabolic cellular responses and processes in testes provide energy production and biosynthetic precursors to regulate germ cell development and control testicular immunity and inflammation. The metabolism of immune cells is crucial for both inflammatory and anti-inflammatory responses, which supposes to affect the spermatogenesis in testes. In this review, the role of immunometabolism in male reproduction will be highlighted. Obesity, metabolic dysfunction, such as type 2 diabetes mellitus, are well documented to impact male fertility; thus, their impacts on the immune cells distributed in testes will also be discussed. Finally, the potential significance of the medicine targeting the specific metabolic intermediates or immune metabolism checkpoints to improve male reproduction will also be reassessed.

Moxibustion Improves Chronic Heart Failure by Inhibiting Autophagy and Inflammation via Upregulation of mTOR Expression

How moxibustion improves chronic heart failure is extremely complex and still unclear. This study aimed to explore whether moxibustion inhibits autophagy and reduces inflammation by regulating mTOR expression to induce myocardial protective effects and alleviate symptoms associated with chronic heart failure. Echocardiography was used to detect cardiac function and cardiac structure of rats, including heart rate (HR), left atrium diameter (LA), left ventricular diameter (LV), left ventricular posterior wall (LVPW), interventricular septum (IVS), ejection fraction (EF), and fractional shortening (FS). BNP and NT-pro BNP levels were measured by enzyme-linked immunosorbent assay (ELISA). Autophagy-associated protein (ATG) genes and mTOR were detected by PCR. The expression of mTOR and phosphorylated-mTOR was detected through western blotting of proteins from myocardial tissue samples. The left ventricular inflammatory response was detected by immunohistochemistry and included ICAM-1, VCAM-1, MMP-2, and MMP-9 expression. The relationship between autophagy and inflammation was analyzed by correlation analysis. The results from echocardiography and ELISA showed that moxibustion could significantly improve heart function and structure. Western blot and PCR results showed that moxibustion treatment elevated mTOR expression. Further, moxibustion could inhibit autophagy and regulate the expression of key autophagy-related genes, including Vps34, ATG3, ATG5, ATG7, ATG12, and ATG13. By contrast, rapamycin could partially reduce the effects of moxibustion. Immunohistochemistry results indicated that moxibustion could reduce myocardial inflammation. Moreover, there was a positive correlation between autophagy and inflammation. Moxibustion can protect cardiac function in rats with heart failure, possibly inhibiting excessive autophagy of cardiomyocytes and reducing inflammatory reactions through the elevation of mTOR expression.

Activated autophagy restored the impaired frequency and function of regulatory T cells in chronic prostatitis

BACKGROUND

Chronic prostatitis or chronic pelvic pain syndrome (CP/CPPS) is a disease with an unclear pathogenesis. Recent studies have reported that regulatory T (Treg) cells might be involved in the development of CP/CPPS. In this study we aimed to examine the functional role of Treg cells and explore the possible regulatory mechanism of Treg cells in CP/CPPS.

METHODS

An experimental autoimmune prostatitis (EAP) mouse model was constructed; the numbers and functions of Treg cells in the EAP and control groups were tested. Then, cell differentiation experiments were conducted to evaluate the regulatory effect of autophagy on Treg cell differentiation. Furthermore, autologous CD4⁺ CD25^- cells and CD4⁺ CD25⁺ cells from the two groups were magnetically sorted and cocultured to observe differences in cellular inhibitory functions. Finally, in an in vivo experiment, rapamycin was intraperitoneally injected into EAP mice for 4 weeks to observe the therapeutic effects.

RESULTS

We found that the number and function of Treg cells in the EAP group were diminished compared to those in the control group. Meanwhile, the tolerance of pain in EAP mice had also decreased. Moreover, after using the autophagy activator rapamycin, the expression of the inflammatory cytokines interleukin-1β was decreased and the pain symptoms were alleviated. A mechanistic study found that autophagy activation promoted the differentiation of Treg and increased the suppressive functions of Treg cells, along with the elevated expression of GATA-3 and cytotoxic T lymphocyte antigen 4 (CTLA-4). Furthermore, in vivo administration of the autophagy activator rapamycin had similar effects on recovering the frequency and function of Treg cells as well as the expression of GATA-3 and CTLA-4.

CONCLUSION

The impaired frequency and function of Treg cells may contribute to the progression of CP/CPPS, and autophagy is a protective mechanism that promotes the differentiation of Treg cells and restores the suppressive functions of Treg cells. Autophagy may be a novel therapeutic option for patients with CP/CPPS.

TRAF3 promotes ROS production and pyroptosis by targeting ULK1 ubiquitination in macrophages

Disrupted mitochondrial function and reactive oxygen species (ROS) generation cause cellular damage and oxidative stress-induced macrophage inflammatory cell death. It remains unclear how mitochondrial dysfunction relates to inflammasome activation and pyroptotic cell death. In this study, we demonstrated that tumor necrosis factor receptor-associated factor 3 (TRAF3) regulates mitochondrial ROS production and promotes TLR agonist LPS plus nigericin (LPS/Ng)-induced inflammasome and pyroptosis in mouse primary macrophages and human monocyte THP-1 cells. Co-IP assays confirmed that TRAF3 forms a complex with TRAF2 and cIAP1 and mediates ubiquitin and degradation of Unc-51 like autophagy activating kinase 1 (ULK1). Moreover, knockdown of ULK1 in THP-1 cells significantly promoted LPS/Ng-induced inflammasome by activating caspase 1 and mature IL-1β. Apoptosis inducing factor (AIF) translocation from mitochondrial to nuclear was observed in ULK1-deficient THP-1 cells under LPS/Ng stimulation, which mediates LPS/Ng-induced cell death in ULK1 deficient macrophages. In conclusion, this study identified a novel role of TRAF3 in regulation of ULK1 ubiquitination and inflammasome signaling and provided molecular mechanisms by which ubiquitination of ULK1 controls mitochondrial ROS production, inflammasome activity, and AIF-dependent pyroptosis.

Rapamycin‑induced autophagy attenuates hormone‑imbalance‑induced chronic non‑bacterial prostatitis in rats via the inhibition of NLRP3 inflammasome‑mediated inflammation

Chronic non-bacterial prostatitis (CNBP) is a common urinary disease and no standard treatments are available at present. Although autophagy serves an important role in a variety of chronic diseases, its role in CNBP is yet to be fully elucidated. Therefore, the present study aimed to investigate the effects of rapamycin-induced autophagy on CNBP by establishing a rat model. In the present study, a total of 30 male Sprague-Dawley rats were randomly divided into three groups (n=10 per group): i) Control, in which rats underwent a sham operation; ii) the model (CNBP), in which rats were castrated and administered 17β-estradiol (0.25 mg/kg via subcutaneous injection) for 30 consecutive days; and iii) rapamycin treatment, in which rats were employed in accordance with the CNBP model, but also received a daily intraperitoneal injection of rapamycin (1 mg/kg) from the 16th day post-surgery for 15 days. Alterations in histology and the levels of autophagy-associated markers, and components of the NLRP3 inflammasome, were measured in the prostate tissues of the rats. The levels of molecules located further downstream of the NLRP3 inflammasome pathway, including interleukin (IL)-1β and IL-18, were also measured. The results demonstrated that, compared with the control group, increased infiltration levels of inflammatory cells and glandular epithelial degeneration were observed in the prostate tissues of rats with CNBP. Furthermore, a significant increase in the concentration of IL-1β and IL-18 in the serum, as well as the increased expression levels of NLRP3, ASC and caspase-1 in prostate tissues were also observed. In addition, reductions in the number of autophagosomes and the expression levels of autophagy-associated, including microtubule-associated protein 1 light chain 3β (LC3B) and Beclin 1, were also detected in the CNBP group; however, treatment with rapamycin reversed these effects. Collectively, the findings of the present study indicated that the NLRP3 inflammasome-mediated inflammatory response was activated by a hormonal imbalance in the prostate glands of rats; however, these effects may be suppressed via rapamycin-induced autophagy.