Divergent Regulation of OCT and MATE Drug Transporters by Cadmium Exposure

Review of Cadmium Bioaccumulation in Fish Exposed to Cadmium

Cadmium (Cd) is a highly toxic substance in the aquatic ecosystem, which can represent a high risk to fish. Fish are exposed to heavy metals through waterborne and dietary pathways, some of which are absorbed by the body and can accumulate in specific tissues without being eliminated. The accumulation varies depending on several factors such as dose, exposure route, exposure time, metal types, and biological status of the fish, and environmental parameters such as DO, salinity, pH, and metal speciation. As Cd speciation occurs in the water, the amount accumulated in the fish can vary, and consuming Cd-accumulated fish can pose a risk to human health. Cd introduced into the body of fish can directly affect blood properties through the circulatory system. Cd introduced into the circulatory system of fish can reach all tissues through the blood flow, and the accumulation of specific tissues is different depending on the blood flow by the energy and oxygen demand of each tissue. Therefore, this review aimed to determine the toxic effects of Cd exposure in fish and identify indicators to assess the extent of Cd bioaccumulation toxicity in fish induced by Cd exposure.

Attenuation of inflammation, oxidative stress and TGF-β1/Smad3 signaling and upregulation of Nrf2/HO-1 signaling mediate the protective effect of diallyl disulfide against cadmium nephrotoxicity

Heavy metals are toxic environmental pollutants with serious health effects on humans and animals. Cadmium (Cd) is known for its serious nephrotoxic effect and its toxicity involves oxidative stress (OS) and inflammation. Diallyl disulfide (DADS), a main constituent of garlic, exhibites cytoprotective and antioxidant activities. This study investigated the effect of DADS on OS, inflammation, and fibrosis induced by Cd in rat kidney, pointing to the involvement of transforming growth factor-β (TGF-β)/Smad3 and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling, and peroxisome proliferator-activated receptor gamma (PPARγ). Rats received DADS for 14 days and Cd on day 7 and blood and kidney samples were collected. Cd elevated serum creatinine, urea and uric acid, provoked kidney histopathological alterations and collagen deposition, increased kidney malondialdehyde (MDA) level, and decreased glutathione (GSH) and antioxidant enzymes. Nuclear factor-kappaB (NF-κB) p65, interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1β, and CD68 were upregulated in Cd-administered rat kidney. DADS prevented kidney injury, mitigated OS, suppressed NF-κB, CD68 and pro-inflammatory mediators, and boosted antioxidants. DADS downregulated TGF-β1, Smad3 phosphorylation and Kelch-like ECH-associated protein-1 (Keap1), and increased Nrf2, HO-1, cytoglobin, and PPARγ. In conclusion, DADS protects the kidney against Cd toxicity by attenuating OS, inflammation, and TGF-β1/Smad3 signaling, and enhancement of Nrf2/HO-1 signaling, antioxidants, and PPARγ.

Farnesol attenuates cadmium-induced kidney injury by mitigating oxidative stress, inflammation and necroptosis and upregulating cytoglobin and PPARγ in rats

Heavy metals are environmental pollutants that can harm animals and humans even at low concentrations. Cadmium (Cd) is known for its serious health effects on different organs and its toxicity is associated with oxidative stress (OS) and inflammation. Farnesol (FAR), a sesquiterpene alcohol found in many vegetables and fruits, possesses promising anti-inflammatory and antioxidant activities. This study evaluated the effect of FAR on Cd-induced kidney injury, pinpointing its effect of the redox status, inflammation, fibrosis and necroptosis. Rats in this study received FAR for 14 days and Cd on day 7. Elevated serum creatinine, urea and uric acid, and several kidney histopathological alterations were observed in Cd-administered rats. Cd increased MDA, decreased antioxidants, downregulated PPARγ and upregulated NF-κB p65, IL-6, TNF-α, and IL-1β. Necroptosis mediators (RIP1, RIP3, MLKL, and caspase-8) and α-SMA were upregulated, and collagen deposition was increased in Cd-administered rats. FAR ameliorated kidney injury markers and tissue damage, attenuated OS, suppressed NF-κB and inflammatory mediators, and enhanced antioxidants. In addition, FAR suppressed RIP1, RIP3, MLKL, caspase-8, and α-SMA, and enhanced kidney cytoglobin and PPARγ. In conclusion, FAR protects against Cd nephrotoxicity by suppressing OS, inflammatory response and necroptosis, effects associated with enhanced antioxidants, cytoglobin, and PPARγ.

Regulation of renal organic cation transporters

Transporters for organic cations (OCs) facilitate exchange of positively charged molecules through the plasma membrane. Substrates for these transporters encompass neurotransmitters, metabolic byproducts, drugs, and xenobiotics. Consequently, these transporters actively contribute to the regulation of neurotransmission, cellular penetration and elimination process for metabolic products, drugs, and xenobiotics. Therefore, these transporters have significant physiological, pharmacological, and toxicological implications. In cells of renal proximal tubules, the vectorial secretion pathways for OCs involve expression of organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs) on basolateral and apical membrane domains, respectively. This review provides an overview of documented regulatory mechanisms governing OCTs and MATEs. Additionally, regulation of these transporters under various pathological conditions is summarized. The expression and functionality of OCTs and MATEs are subject to diverse pre- and post-translational modifications, providing insights into their regulation in various pathological conditions. Typically, in diseases, downregulation of transporter expression is observed, probably as a protective mechanism to prevent additional damage to kidney tissue. This regulation may be attributed to the intricate network of modifications these transporters undergo, shedding light on their dynamic responses in pathological contexts.

Interactions of Betel Quid Constituents with Drug Disposition Pathways: An Overview

Global estimates indicate that over 600 million individuals worldwide consume the areca (betel) nut in some form. Nonetheless, its consumption is associated with a myriad of oral and systemic ailments, such as precancerous oral lesions, oropharyngeal cancers, liver toxicity and hepatic carcinoma, cardiovascular distress, and addiction. Users commonly chew slivers of areca nut in a complex consumable preparation called betel quid (BQ). Consequently, the user is exposed to a wide array of chemicals with diverse pharmacokinetic behavior in the body. However, a comprehensive understanding of the metabolic pathways significant to BQ chemicals is lacking. Henceforth, we performed a literature search to identify prominent BQ constituents and examine each chemical's interplay with drug disposition proteins. In total, we uncovered over 20 major chemicals (e.g., arecoline, nicotine, menthol, quercetin, tannic acid) present in the BQ mixture that were substrates, inhibitors, and/or inducers of various phase I (e.g., CYP, FMO, hydrolases) and phase II (e.g., GST, UGT, SULT) drug metabolizing enzymes, along with several transporters (e.g., P-gp, BCRP, MRP). Altogether, over 80 potential interactivities were found. Utilizing this new information, we generated theoretical predictions of drug interactions precipitated by BQ consumption. Data suggests that BQ consumers are at risk for drug interactions (and possible adverse effects) when co-ingesting other substances (multiple therapeutic classes) with overlapping elimination mechanisms. Until now, prediction about interactions is not widely known among BQ consumers and their clinicians. Further research is necessary based on our speculations to elucidate the biological ramifications of specific BQ-induced interactions and to take measures that improve the health of BQ consumers.

Platinum-Induced Peripheral Neuropathy (PIPN): ROS-Related Mechanism, Therapeutic Agents, and Nanosystems

Platinum (Pt) drugs (e.g., oxaliplatin, cisplatin) are applied in the clinic worldwide for the treatment of various cancers. However, platinum-induced peripheral neuropathy (PIPN) caused by the accumulation of Pt in the peripheral nervous system limits the clinical application, whose prevention and treatment are still a huge challenge. To date, Pt-induced reactive oxygen species (ROS) generation has been studied as one of the primary mechanisms of PIPN, whose downregulation would be feasible to relieve PIPN. This review will discuss ROS-related PIPN mechanisms including Pt accumulation in the dorsal root ganglia (DRG), ROS generation, and cellular regulation. Based on them, some antioxidant therapeutic drugs will be summarized in detail to alleviate the Pt-induced ROS overproduction. More importantly, we focus on the cutting-edge nanotechnology in view of ROS-related PIPN mechanisms and will discuss the rational fabrication of tailor-made nanosystems for efficiently preventing and treating PIPN. Last, the future prospects and potential breakthroughs of these anti-ROS agents and nanosystems will be briefly discussed.