Signaling interplay between PARP1 and ROS regulates stress-induced cell death and developmental changes in Dictyostelium discoideum

Sunitinib induces cardiotoxicity through modulating oxidative stress and Nrf2-dependent ferroptosis in vitro and in vivo

SUN, a multi-targeted tyrosine kinase inhibitor, exerts cardiotoxicity which hinders its clinical use. It is necessary to elucidate molecular mechanism of SUN-induced cardiotoxicity. To elucidate molecular mechanism of SUN-induced cardiotoxicity and whether it is related to Nrf2-dependent ferroptosis, in vitro model with H9c2 cells derived from rat heart tissue and in vivo model (C57BL/6J male mouse) were used in the present study. In vivo model was established by oral treatment of SUN at dose of 10, 20, 40 mg/kg for 14 days. Body weight, ECG, plasma enzyme activities, histology staining were performed to evaluate heart function. Western-blot was performed to analyze the level of ferroptosis-related proteins. In vitro results indicated that SUN markedly induced ferroptosis embodied as collapsed MMP, accumulated iron and elevated ROS. In vivo results showed that SUN significantly impaired cardiac function. Abnormal electrocardiogram, increased serum CK and lactate LDH levels were significantly observed in SUN groups. Histology staining showed that SUN caused structural injuries and fibrosis deposition. Moreover, SUN increased the level of MDA and Fe2+ content, decreased the level of GSH. Both in vitro and in vivo experiments indicated that SUN reduced the expression of Nrf2, HO-1, NQO1, GPX4 and FTH1, enhanced the TfR expression. This study suggested that oxidative stress and Nrf2-dependent ferroptosis played a vital role in SUN-induced cardiotoxicity.

PARP inhibitor olaparib induced differential protein expression in cervical cancer cells

PARP inhibitors are a potential class of chemotherapeutic drugs but PARP inhibitor response has not been explored systematically. We lack a specific understanding of the subset of the proteome preferentially modified in various cancers by PARP inhibitors. Implications of PARP inhibitor and PARP1 in cervical cancer treatment and resistance are not fully elucidated. We conducted a mass spectrometry-based proteomic analysis of cervical cancer Hela cells treated with olaparib. We aimed to identify the alteration in the protein signaling pathway induced by PARP inhibitors beyond the DNA damage response pathway. Our data demonstrate a significant reduction in PARP activity and enhanced cell death after olaparib treatment. We further observed articulated proteomic changes with a significant enrichment of proteins in diverse cellular processes. The differentially expressed proteins were predominantly associated with RNA metabolism, mRNA splicing, processing, and RNA binding. Our data also identified proteins that could probably contribute to survival mechanisms resulting in resistance to PARP inhibitors. Hence, we put forth the overview of proteomic changes induced by PARP inhibitor olaparib in cervical cancer cells. This study highlights the significant proteins modified during PARP inhibition and thus could be a probable target for combination therapies with PARP inhibitors in cervical cancer. SIGNIFICANCE.

Ergothioneine attenuates varicocele-induced testicular damage by upregulating HSP90AA1 in rats

This study investigates the therapeutic effect and the underlying mechanisms of ergothioneine (EGT) on the testicular damage caused by varicocele (VC) in vivo, in vitro, and in silico. This preclinical study combines a series of biological experiments and network pharmacology analyses. A total of 18 Sprague Dawley (SD) male rats were randomly and averagely divided into three groups: the sham-operated, VC model, and VC model with EGT treatment (VC + EGT) groups. The left renal vein of the VC model and the VC + EGT groups were half-ligated for 4 weeks. Meanwhile, the VC + EGT group was intragastrically administrated with EGT (10 mg/kg). GC1 and GC2 cells were exposed to H₂ O₂ with or without EGT treatment to re-verify the conclusion. The structure disorder of seminiferous tubules ameliorated the apoptosis decrease in the VC rats receiving EGT. EGT can also increase the sperm quality of the VC model rats (p < 0.05). The exposure to H₂ O₂ decreased proliferation and increased apoptosis of GC1 and GC2 cells, which was revisable by adding EGT to the plates (p < 0.05). The network pharmacology and molecular docking were conducted to explore the potential targets of EGT in VC, and HSP90AA1 was identified as the pivotal gene, which was validated by western blot, immunohistochemistry, and RT-qPCR both in vivo and in vitro (p < 0.05). Overall, EGT attenuates the testicular injury in the VC model both in vivo and in vitro by potentially potentiating the expression of HSP90AA1.

Is Parthanatos Involved in Varicocele?

Varicoceles (VCs) have received widespread attention as a primary factor affecting male fertility and a pathological condition that may lead to decreased sperm count and motility in patients. Many studies have shown that an imbalance of local antioxidant balance exists in patients with VC, leading to an obvious increase in the content of reactive oxygen species (ROS) and may cause reductive stress. Excessive ROS may aggravate spermatogenesis dysfunction and affect male fertility. Poly(ADP-ribose) polymerase (PARP) is an enzyme associated with DNA repair in eukaryotic cells, can be activated by DNA fragments with structural damage, and has been considered a DNA damage receptor in DNA damage repair and apoptosis. We built a rat model of VC and an oxidative damage model of a spermatocyte-derived cell line (GC-2 cells) induced by hydrogen peroxide to study the role of PARP1 in VC. Differentially expressed genes (DEGs) were obtained by RNA sequencing in the testes of VC rats. Analysis of DEGs revealed some genes with significantly altered expression, which were validated in rat and cell models. Immunofluorescence, real-time quantitative PCR analysis, Western blot, and flow cytometry were used to analyze the changes between the control group and the VC or hydrogen peroxide group. Overall, we found that PARP1 protein expression increased in VC rats and in the hydrogen peroxide-induced oxidative stress model of GC-2 cells. Parthanatos may be one of the factors leading to reduced reproductive capacity in VC patients. Our study provides novel insights into the mechanisms of male infertility induced by oxidative stress and provides a new therapeutic target for VC.

Identification and characterization of Poly(ADP-ribose) polymerase-1 interacting proteins during development of Dictyostelium discoideum

Poly (ADP-ribose) polymerase-1 (PARP-1) is a multifunctional protein that is associated with various biological processes like chromatin remodeling, DNA damage, cell death etc. In Dictyostelium discoideum, PARP-1 has also been implicated in cellular differentiation and development. However, its interacting proteins during multicellular development are not yet explored. Hence, the present study aims to identify PARP-1 interacting proteins during multicellular development of D. discoideum. BRCA1 C-terminus (BRCT) domain of PARP-1, which is mainly involved in protein-protein interactions was cloned in pGEX4T1 vector and developmental interactome of PARP-1 were analyzed by affinity purification-mass spectrometry. These interactions were further confirmed by in-silico protein-protein docking analysis, which led to identification of the proteins that show high affinity for BRCT domain. Initially, the protein structures were modeled on SWISS MODEL and PHYRE2 servers, refined by 3Drefine and validated by PROCHECK. Further, interaction sites of BRCT and the conserved regions in all interacting proteins were predicted using cons-PPISP and ConSurf, respectively. Finally, protein-protein docking analysis was done by HADDOCK. Our results identified 19 possible BRCT interacting proteins during D. discoideum development. Furthermore, interacting residues involved in the interactions and functional regions were explored. This is the first report where PARP-1's developmental interactome in D. discoideum is well established. The current findings demonstrate PARP-1's developmental interactome in D. discoideum and provide the groundwork to understand its regulated functions in developmental biology which would undoubtedly extend our perception towards developmental diseases in higher complex organisms and their treatment.