The potent analgesia of intrathecal 2R, 6R-HNK via TRPA1 inhibition in LF-PENS-induced chronic primary pain model.
作者: An-Ran Liu ; Zhen-Jia Lin ; Ming Wei ; Yuan Tang ; Hui Zhang ; Xiang-Ge Peng ; Ying Li ; Yu-Fan Zheng ; Zhi Tan ; Li-Jun Zhou ; Xia Feng
Chronic primary pain (CPP) is an intractable pain of unknown cause with significant emotional distress and/or dysfunction that is a leading factor of disability globally. The lack of a suitable animal model that mimic CPP in humans has frustrated efforts to curb disease progression. 2R, 6R-hydroxynorketamine (2R, 6R-HNK) is the major antidepressant metabolite of ketamine and also exerts antinociceptive action. However, the analgesic mechanism and whether it is effective for CPP are still unknown.
Based on nociplastic pain is evoked by long-term potentiation (LTP)-inducible high- or low-frequency electrical stimulation (HFS/LFS), we wanted to develop a novel CPP mouse model with mood and cognitive comorbidities by noninvasive low-frequency percutaneous electrical nerve stimulation (LF-PENS). Single/repeated 2R, 6R-HNK or other drug was intraperitoneally (i.p.) or intrathecally (i.t.) injected into naïve or CPP mice to investigate their analgesic effect in CPP model. A variety of behavioral tests were used to detect the changes in pain, mood and memory. Immunofluorescent staining, western blot, reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) and calcium imaging of in cultured dorsal root ganglia (DRG) neurons by Fluo-8-AM were used to elucidate the role and mechanisms of 2R, 6R-HNK in vivo or in vitro.
Intrathecal 2R, 6R-HNK, rather than intraperitoneal 2R, 6R-HNK or intrathecal S-Ketamine, successfully mitigated HFS-induced pain. Importantly, intrathecal 2R, 6R-HNK displayed effective relief of bilateral pain hypersensitivity and depressive and cognitive comorbidities in a dose-dependent manner in LF-PENS-induced CPP model. Mechanically, 2R, 6R-HNK markedly attenuated neuronal hyperexcitability and the upregulation of calcitonin gene-related peptide (CGRP), transient receptor potential ankyrin 1 (TRPA1) or vanilloid-1 (TRPV1), and vesicular glutamate transporter-2 (VGLUT2) in peripheral nociceptive pathway. In addition, 2R, 6R-HNK suppressed calcium responses and CGRP overexpression in cultured DRG neurons elicited by the agonists of TRPA1 or/and TRPV1. Strikingly, the inhibitory effects of 2R, 6R-HNK on these pain-related molecules and mechanical allodynia were substantially occluded by TRPA1 antagonist menthol.
In the newly designed CPP model, our findings highlighted the potential utility of intrathecal 2R, 6R-HNK for preventing and therapeutic modality of CPP. TRPA1-mediated uprgulation of CGRP and neuronal hyperexcitability in nociceptive pathways may undertake both unique characteristics and solving process of CPP.
2023-10-14·Bioscience, biotechnology, and biochemistry
Capsaicin indirectly regulates TRPA1 via the arachidonic acid cascade, resulting in TJ opening.
Capsaicin induces the reversible opening of tight junctions (TJs) and enhances the delivery of hydrophilic macromolecules through a paracellular route. We previously revealed that TRPA1 is involved in the capsaicin-induced Ca2+ influx and TJ permeability increase, although there are no reports that capsaicin directly activates TRPA1. In this study, we investigated the upstream factors of TRPA1 using RNA-seq analysis, and found that the cyclooxygenase 2 (COX2) gene was upregulated by capsaicin. COX2 converts arachidonic acid (AA), a metabolite by phospholipase A2 (PLA2), to prostaglandins. Prostaglandin E2 (PGE2) production was stimulated by capsaicin, and capsaicin-induced Ca2+ influx was effectively inhibited by PLA2 and COX2 inhibitors. The AA-induced TJ permeability increase was inhibited by a TRPA1 antagonist, but the capsaicin- and AA-induced TJ permeability increases were hardly inhibited by a COX2 inhibitor. These results suggest that capsaicin-induced PLA2 activation and AA production are the important steps for the TJ permeability increase.
2023-10-05·Journal of translational medicine
TRPA1 promotes cisplatin-induced acute kidney injury via regulating the endoplasmic reticulum stress-mitochondrial damage.
作者: Fei Deng ; Heping Zhang ; Wei Zhou ; Shijie Ma ; Yuwei Kang ; Wei Yang ; Liangbin Zhao ; Wei Qin
Cisplatin is a widely used and effective chemotherapeutic agent against cancer. However, nephrotoxicity is one of the most common side effects of cisplatin, and it can proceed to acute kidney injury (AKI). Studies have reported that activation of transient receptor potential ankyrin-1 (TRPA1) mediates cisplatin-induced renal tubular cytotoxic injury. The aim of this study was to investigate the mechanism of TRPA1 in promoting cisplatin-induced AKI through modulation of the endoplasmic reticulum stress (ERS)-mitochondrial damage.
A cisplatin-induced HK-2 cell model in vitro and mouse model in vivo were established. The mechanism of TRPA1 promotes AKI was elucidated by H&E staining, TUNEL staining, transmission electron microscope (TEM), immunofluorescence, CCK-8 viability assays, flow cytometry, Western blotting, JC-1 assay, and enzyme linked immunosorbent assay (ELISA).
In vivo and in vitro, HC-030031 reduced cisplatin-induced Scr and BUN level elevations; improved cisplatin-induced renal tissue injury, apoptosis, and mitochondrial dysfunction; elevated the reduced ERS-associated proteins glucose-regulated protein 78 (GRP78), glucose-regulated protein 75 (GRP75), and C/EBP homologous protein (CHOP) levels induced by cisplatin; reduced the elevated optic atrophy 1 (OPA1), mito-fusion 1 (MFN1), and mito-fusion 2 (MFN2) protein levels, and elevated phospho-dynamin-related protein 1 (p-DRP1) and mitochondrial fission factor (MFF) protein levels. HC-030031 also reduced the mitochondria-associated endoplasmic reticulum membrane (MAM) structure. In addition, TRPA1 agonists also decreased cell proliferation, increased apoptosis, and triggered mitochondrial dysfunction and calcium overload in HK-2 cells via modulation of MAM. ERS inhibitors and GRP75 inhibitors reversed these changes caused by TRPA1 agonists.
Our findings suggest that TRPA1 enhances cisplatin-induced AKI via modulation of ERS and mitochondrial damage.
Rezpeb failed to meet expectations in a phase 2 lupus study back in February. At the time, Eli Lilly said it would drop that indication and reassess whether to continue in atopic dermatitis.
The writing was on the wall for Nektar Therapeutics and Eli Lilly’s rezpeg collaboration, but, now, the Big Pharma is etching it in permanent marker. Rights for the T regulatory cell stimulator treatment are now headed back to the biotech.
Lilly made the change official in its first-quarter earnings report Thursday. A slide presentation noted that rezpeg, or rezpegaldesleukin, was being dropped from phase 2. Nektar confirmed the news in a separate release, announcing plans to push forward with rezpeg in atopic dermatitis.
Rezpeb failed to meet expectations in a phase 2 lupus study back in February. At the time, Lilly said it would drop that indication and reassess whether to continue in atopic dermatitis. Nektar needed the lupus partnership to work after lead asset bempeg, partnered with Bristol Myers Squibb, blew up in the clinic in 2022.
Nektar President and CEO Howard Robin said the company is pleased to have rezpeb back and pledged to move quickly to get a phase 2b study underway for moderate to severe atopic dermatitis. Nektar will also consider other indications for the therapy.
“We believe the strong data generated to-date for rezpeg in atopic dermatitis show the significant potential for rezpeg to emerge as an innovative new mechanism with the possibility of disease resolution in a growing biologic treatment field,” Robin said in the release.
Lilly and Nektar previously presented early-stage proof-of-concept data in atopic dermatitis showing that rezpeg stimulates Tregs to target the immune system imbalance, improving disease activity in patients. Nektar believes that the therapy has the potential to have a quarterly maintenance dosing schedule and improve long-term disease control.
Nektar announced a strategic reprioritization and cost restructuring plan earlier this month, noting that immunology, including rezpeg, would be its new focus—with or without Lilly. The company also laid off 60% of staff at that time. Nektar previously let go of 70% of its employees a year earlier.
Lilly is also shelving two more meds, according to the earnings release. Alzheimer’s treatment solanezumab is officially out of the pipeline after a decadelong test ended in failure last month. The end of the study concludes Lilly's development of solanezumab, Chief Scientific and Medical Officer Daniel Skovronsky, M.D., Ph.D., told investors during a Thursday morning earnings call.
The antibody targets soluble amyloid beta, and Lilly thought that dosing patients earlier in the course of disease would be key to eliciting a response. Unfortunately, the trial, which began in 2013, found that solanezumab failed to slow cognitive decline and missed the primary endpoint. Skovronsky said the results were not a surprise, given more recent learnings in Alzheimer's.
Solanezumab was previously abandoned in 2016 after a phase 3 fail in people with mild dementia due to Alzheimer's disease. It was also unsuccessful in more advanced Alzheimer’s patients in earlier testing.Lilly is expecting a major readout for its star Alzheimer's candidate donanemab in the second quarter of this year.
The other med to be cut is a TRPA1 antagonist for pain, according to Lilly’s presentation.
Headline results for the first quarter: Revenue: $7 billion, down 11% Profit: $1.3 billion, down 29%Note: All changes are versus the prior-year period unless otherwise statedWhat the company said:"Core business growth drove solid first-quarter financial results and a strong start for Eli Lilly in 2023, which includes pipeline progress led by positive SURMOUNT-2 data for tirzepatide in obesity," remarked CEO David Ricks.The company said the decline in volumes was driven by $1.5 billion in revenue from COVID-19 antibodies in the first quarter of 2022. Excluding COVID-19 antibodies, Eli Lilly said sales in the first three months of this year were up 10%, with new products contributing $573.6 million.Other results: US revenue: $4.4 billion, down 14%, with Eli Lilly noting that excluding COVID-19 antibodies, revenue in the US jumped 19%, primarily driven by Mounjaro, Trulicity and Verzenio Non-US revenue: $2.5 billion, down 4%, hit by the impact of foreign exchange rates Key growth products: $4.6 billion, up 18% Trulicity: $2 billion, up 14%, with delays in fulfilling certain US orders of the drug persisting through the first quarter, "but at a reduced level" Verzenio: $750.9 million, up 60%, driven by increased demand Jardiance: $577.5 million, up 38% Mounjaro: $568.5 million, following its approval by the FDA last May to improve glucose control in adults with type 2 diabetes Taltz: $527million, up 8% Cyramza: $236.8 million, up 3% Olumiant: $228.9 million, down 10%, driven by a decline in its use as a COVID-19 treatment Emgality: $154.3 million, up 3% Humalog: $460.9 million, down 25% Alimta: $58.2 million, down 83%Looking ahead:Eli Lilly bumped up its sales guidance for 2023 by $900 million to between $31.2 billion and $31.7 billion, driven by approximately $650 million associated with updates to foreign exchange rate assumptions, with the remainder attributed to underlying business performance. It is also projecting higher earnings for the year, to between $8.65 and $8.85 per share, up from a prior range of $8.35 to $8.55 per share.Pipeline update:The earnings call coincided with Eli Lilly releasing the latest data on its once-weekly dual GIP and GLP-1 receptor agonist Mounjaro in obesity, paving the way for the company to complete its rolling submission to the FDA for that indication.The company also disclosed that it removed a Phase II TRPA1 antagonist from its pipeline that was under development to treat pain.