Systems Pharmacology Modeling Identifies a Novel Treatment Strategy for Bortezomib-Induced Neuropathic Pain

Dynll1-PI31 Interaction Enhances Proteolysis Through the Proteasome, Representing a Novel Therapeutic Target for INF2-Related FSGS

Key Points

The R218Q mutation disrupts sequestration of Dynll1 by inverted formin 2, promotes Dynll1-PI31 interaction, and enhances proteasome-mediated nephrin degradation. Suppression of proteasome-mediated proteolysis with proteasome inhibitors is a new therapeutic strategy for inverted formin 2-mediated FSGS.

Background

The p.Arg218Gln (R218Q) mutation in the inverted formin 2 (INF2 ) gene causes podocytopathy prone to FSGS. This mutation disrupts the ability of INF2 to sequester dynein light chain 1 (DYNLL1), thus promoting dynein-mediated mistrafficking of the slit diaphragm protein, nephrin, to proteolytic pathways. Bortezomib, a proteasome inhibitor, stabilizes nephrin in R218Q knockin (KI) podocytes, suggesting a role for the ubiquitin proteasome system (UPS) in dynein-driven pathogenesis. However, the link between dynein and the UPS is unknown. This study tested the hypothesis that INF2 R218Q promotes proteasome-mediated degradation of nephrin through an increased interaction between Dynll1 and the proteasomal inhibitor of 31kD (PI31), a Dynll1 adaptor that potentially couples the UPS with dynein cargoes.

Methods

The essential role of PI31 in UPS-mediated degradation of nephrin, a known dynein cargo, was studied in cultured R218Q KI mouse podocytes by applying genetic or chemical interventions to inhibit the activity of PI31 or of the proteasome. The protective effect of bortezomib in dynein-driven podocytopathy and FSGS was tested in R218Q KI mice challenged with puromycin aminonucleoside, a murine model of FSGS.

Results

The R218Q mutation in INF2 disrupted sequestration of Dynll1 by INF2, allowing Dynll1 to be captured by PI31 and promoting dynein-mediated transport of nephrin to the proteasome. Each of the following manipulations was sufficient to restore nephrin proteostasis in R218Q KI podocytes: knocking down Dynll1 or PI31 , inactivating dynein, or inhibiting the activity of the proteasome. In R218Q KI mice challenged with puromycin aminonucleoside, dynein-mediated mistrafficking and depletion of nephrin were correlated with increased Dynll1-PI31 interaction; the resulting podocytopathy and FSGS were ameliorated by bortezomib.

Conclusions

The Dynll1-PI31 interaction facilitates dynein-driven trafficking of nephrin to the proteasome and proteasome-mediated degradation of nephrin in INF2-R218Q-mediated podocytopathy. This mechanism offers new therapeutic strategies for INF2-related FSGS by using pharmacologically available proteasome inhibitors.

An emerging aspect of cancer neuroscience: A literature review on chemotherapy-induced peripheral neuropathy

The nervous system governs both ontogeny and oncology. Foundational discoveries have clarified the direct communication of neurotransmitters with tumors and indirect interactions through neural effects on the immune system and the tumor microenvironment. Meantime, the nervous system is susceptible to cancer and its treatment. Chemotherapy-induced peripheral neuropathy (CIPN) is the most common side effects that significantly reduce the efficacy of anti-cancer treatment and patients' quality of life by leading to dose reduction or early cessation of chemotherapy. However, there are no effective strategies to reverse or treat CIPN. A better understanding of the mechanisms is expected to enable the development of the next generation of therapies. Here, we summarize the recent important studies on clinical manifestations, risk factors, prediction, pathogenesis, prevention, and treatment of CIPN. We also provide perspectives and insights regarding the rationales of bidirectional interactions between cancer and the nervous system.

Optimal strategies of oncolytic virus-bortezomib therapy via the apoptotic, necroptotic, and oncolysis signaling network

Bortezomib and oncolytic virotherapy are two emerging targeted cancer therapies. Bortezomib, a proteasome inhibitor, disrupts protein degradation in cells, leading to the accumulation of unfolded proteins that induce apoptosis. On the other hand, virotherapy uses genetically modified oncolytic viruses (OVs) to infect cancer cells, trigger cell lysis, and activate anti-tumor response. Despite progress in cancer treatment, identifying administration protocols for therapeutic agents remains a significant concern, aiming to strike a balance between efficacy, minimizing toxicity, and administrative costs. In this work, optimal control theory was employed to design a cost-effective and efficient co-administration protocols for bortezomib and OVs that could significantly diminish the population of cancer cells via the cell death program with the NF$ \kappa $B-BAX-RIP1 signaling network. Both linear and quadratic control strategies were explored to obtain practical treatment approaches by adapting necroptosis protocols to efficient cell death programs. Our findings demonstrated that a combination therapy commencing with the administration of OVs followed by bortezomib infusions yields an effective tumor-killing outcome. These results could provide valuable guidance for the development of clinical administration protocols in cancer treatment.

Recent advances in the treatment and prevention of peripheral neuropathy after multiple myeloma treatment

The incidence of multiple myeloma (MM) is increasing year by year, requiring chemotherapy drugs to control the condition. With the advent of new proteasome inhibitors, immunomodulators, and monoclonal antibodies, the prognosis of patients has improved significantly. However, peripheral neuropathy caused by drugs limits the dose and duration of treatment, which seriously affects patients' quality of life and treatment outcome. Although the neuropathies induced by chemotherapy drugs have attracted much attention, their mechanism and effective prevention and treatment measures are not clear. Therefore, how to alleviate peripheral neuropathy caused by drugs for treatment of MM is a key issue in improving patients' quality of life and prolonging their survival time, which have some clinical value. In this paper, we review the current research on the pathogenesis, pharmacological and nonpharmacological treatment, and prevention, which expects to present instruction for peripheral neuropathy after treatment of MM.

Network pharmacology-based research on the effect of angelicin on osteosarcoma and the underlying mechanism

To explore the antitumor effects of angelicin on osteosarcoma and the underlying mechanism. We aimed to elucidate the mechanism by network pharmacology, molecular docking, and in vitro experiments. We analyzed a PPI network of potential angelicin targets in the treatment of osteosarcoma and identified hub targets. We systematically performed GO and KEGG enrichment analyses of the potential targets of angelicin, and we predicted it function in osteosarcoma treatment and the underlying molecular mechanism. Through molecular docking, the interactions between hub targets and angelicin were simulated, and then, the hub targets of angelicin were identified. Based on these results, we validated the effects of angelicin on osteosarcoma cells by conducting in vitro experiments. The PPI network analysis of potential therapeutic targets identified four apoptosis-related hub targets, namely, BCL-2, Casp9, BAX and BIRC 2. GO and KEGG enrichment analyses demonstrated that angelicin regulates osteosarcoma cell apoptosis. Molecular docking results indicated that angelicin can freely bind to the hub targets listed above. In vitro experiments showed that angelicin promoted osteosarcoma cell apoptosis in a dose-dependent manner and inhibited osteosarcoma cell migration and proliferation in a time- and dose-dependent manner. The RT-PCR results showed that angelicin simultaneously promoted the mRNA expression of Bcl-2 and Casp9 and inhibited the mRNA expression of BAX and BIRC 2. Angelicin promotes osteosarcoma cell apoptosis and inhibits osteosarcoma cell proliferation and migration by activating a signaling network that is composed of hub targets that link multiple signaling pathways. Angelicin could become an alternative drug for the treatment of osteosarcoma.

MecDDI: Clarified Drug-Drug Interaction Mechanism Facilitating Rational Drug Use and Potential Drug-Drug Interaction Prediction

Drug-drug interactions (DDIs) are a major concern in clinical practice and have been recognized as one of the key threats to public health. To address such a critical threat, many studies have been conducted to clarify the mechanism underlying each DDI, based on which alternative therapeutic strategies are successfully proposed. Moreover, artificial intelligence-based models for predicting DDIs, especially multilabel classification models, are highly dependent on a reliable DDI data set with clear mechanistic information. These successes highlight the imminent necessity to have a platform providing mechanistic clarifications for a large number of existing DDIs. However, no such platform is available yet. In this study, a platform entitled "MecDDI" was therefore introduced to systematically clarify the mechanisms underlying the existing DDIs. This platform is unique in (a) clarifying the mechanisms underlying over 1,78,000 DDIs by explicit descriptions and graphic illustrations and (b) providing a systematic classification for all collected DDIs based on the clarified mechanisms. Due to the long-lasting threats of DDIs to public health, MecDDI could offer medical scientists a clear clarification of DDI mechanisms, support healthcare professionals to identify alternative therapeutics, and prepare data for algorithm scientists to predict new DDIs. MecDDI is now expected as an indispensable complement to the available pharmaceutical platforms and is freely accessible at: https://idrblab.org/mecddi/.

Lysosomal dysfunction in Schwann cells is involved in bortezomib-induced peripheral neurotoxicity

Bortezomib (BTZ) is a proteasome inhibitor serves as a first-line drug for multiple myeloma treatment. BTZ-induced peripheral neuropathy (BIPN) is the most common adverse effect of BTZ with an incidence as high as 40-60%. However, the pathological mechanisms underlying BIPN remain largely unclear. BTZ leads to dramatic Schwann cell demyelination in sciatic nerves. Previous studies implied that myelin debris was predominantly degraded via autophagy-lysosome pathway in Schwann cells. However, the association of autophagy with BIPN has not been made. Mice were treated with BTZ (2 mg/kg, i.v.) on Day1 and Day4 each week for continuous 4 weeks. BTZ-treated mice showed enhanced mechanical hyperalgesia, decreased tail nerve conduction and sciatic nerve demyelination. Unexpectedly, BTZ led to the accumulation of autophagic vesicles, LC3-II and p62 in the sciatic nerve. Moreover, BTZ blocked autophagic flux in RSC96 Schwann cells as determined by mcherry-GFP-LC3 assay, suggesting BTZ may impair lysosomal function rather than inducing autophagy in Schwann cells. BTZ significantly reduced the lysosomal activity in Schwann cells as determined by reduced LysoTracker Red and DQ-Red-BSA staining and increased the level of immature Cathepsin B (CTSB). Remarkably, lysosomal activators PP242 and Torin1, significantly reversed the blockage of autophagic flux by BTZ. We further verified that Torin1 rescued the demyelination, nerve conduction and reduced the mechanical hyperalgesia in BIPN mice. Additionally, Torin1 did not compromise the efficacy of BTZ in suppressing multiple myeloma RPMI8226 cell. Taken together, we identified that lysosomal dysfunction in Schwann cells caused by BTZ is involved in the BIPN pathology. Improved lysosomal function in Schwann cells can be a promising strategy for BIPN treatment.