Realgar increases defenses against infection by Enterococcus faecalis in Caenorhabditis elegans

Toxicity study of mineral medicine haematitum

ETHNOPHARMACOLOGICAL RELEVANCE

Haematitum, a time-honored mineral-based Chinese medicine, has been used medicinally in China for over 2000 years. It is now included in the Chinese Pharmacopoeia and used clinically for treating digestive and respiratory diseases. The Chinese Materia Medica records that it is toxic and should not be taken for a long period, but there are few research reports on the toxicity of Haematitum and its potential toxicity mechanisms.

AIM OF THE STUDY

This study aimed to evaluate the toxicity of Haematitum and calcined Haematitum, including organ toxicity, neurotoxicity, and reproductive toxicity. Further, it is also necessary to explore the mechanism of Haematitum toxicity and to provide a reference for the safe clinical use of the drug.

MATERIALS AND METHODS

The samples of Haematitum and calcined Haematitum decoctions were prepared. KM mice were treated with samples by gavage for 10 days, and lung damage and apoptosis were assessed by HE staining and TUNEL staining of lung tissues respectively. Metabolomics analysis was performed by HPLC-MS. Metallomics analysis was performed by ICP-MS. In addition, C. elegans was used as a model for 48 h exposure to examine the neurotoxicity and reproductive toxicity-related indices of Haematitum, including locomotor behaviors, growth and development, reproductive behaviors, AChE activities, sensory behaviors, apoptosis, and ROS levels.

RESULTS

The use of large doses of Haematitum decoction caused lung damage in mice. Neither calcined Haematitum decoction nor Haematitum decoction at clinically used doses showed organ damage. Metabolomics results showed that disorders in lipid metabolic pathways such as sphingolipid metabolism and glycerophospholipid metabolism may be important factors in Haematitum-induced pulmonary toxicity. High doses of Haematitum decoction caused neurological damage to C. elegans, while low doses of Haematitum decoction and calcined Haematitum decoction showed no significant neurotoxicity. Decoction of Haematitum and calcined Haematitum did not show reproductive toxicity to C. elegans. Toxicity was also not observed in the control group of iron (Ⅱ) and iron (Ⅲ) ions in equal amounts with high doses of Haematitum.

CONCLUSIONS

Haematitum is relatively safe for routine doses and short-term use. Calcination can significantly reduce Haematitum toxicity, and this study provides a reference for safe clinical use.

Ovalbumin promotes innate immune response of Caenorhabditis elegans through DAF-16 and SKN-1 pathways in insulin/IGF-1 signaling

Ovalbumin (OVA) is a major allergen in eggs and could induce severe allergic reactions in sensitive individuals, where the innate immune system works as a regulator. The mechanism of how innate immunity adjusts to food allergy is relatively well-studied, however, the effects of allergen uptake on the innate immune system remain unclear. Therefore, the Caenorhabditis elegans (C. elegans) model was utilized to assess the effects of OVA on its innate immune system. OVA enhanced the immune response of C. elegans with higher survival rates under Pseudomonas aeruginosa infection. Moreover, sustaining OVA treatment improved the health states that were reflected in the prolonged lifespan, alleviated oxidative stress, accelerated growth, and promoted motility. RNA-sequencing analysis and the slow-killing assays in the mutants of insulin/IGF-1 signaling (IIS)-related genes confirmed that IIS was necessary for OVA to regulate innate immunity. Besides, OVA activated SKN-1 temporarily and facilitated the nuclear localization of DAF-16 for improving immunity and health status in C. elegans. Together, OVA could enhance the innate immune responses via DAF-16 and SKN-1 pathways in the IIS of C. elegans, and this work will provide novel insights into the regulation of innate immunity by OVA in higher organisms.

Multifunctional Nano-Realgar Hydrogel for Enhanced Glioblastoma Synergistic Chemotherapy and Radiotherapy: A New Paradigm of an Old Drug

Purpose

Realgar, as a kind of traditional mineral Chinese medicine, can inhibit multiple solid tumor growth and serve as an adjuvant drug in cancer therapy. However, the extremely low solubility and poor body absorptive capacity limit its application in clinical medicine. To overcome this therapeutic hurdle, realgar can here be fabricated into a nano-realgar hydrogel with enhanced chemotherapy and radiotherapy (RT) ability. Our objective is to evaluate the superior biocompatibility and anti-tumor activity of nano-realgar hydrogel.

Methods

We have successfully synthesized nano-realgar quantum dots (QDs) coupling with 6-AN molecules (NRA QDs) and further encapsulated with a pH-sensitive dextran hydrogel carrier with hyaluronic acid coating (DEX-HA gel) to promote bioavailability, eventually forming a multifunctional nano-realgar hydrogel (NRA@DH Gel). To better investigate the tumor therapy efficiency of the NRA@DH Gel, we have established the mice in situ bearing GL261 brain glioblastoma as animal models assigned to receive intratumor injection of NRA@DH Gel.

Results

The designed NRA@DH Gel as an antitumor drug can not only exert the prominent chemotherapy effect but also as a "sustainable reactive oxygen species (ROS) generator" can inhibit in the pentose phosphate pathway (PPP) metabolism and reduce the production of nicotinamide adenine dinucleotide phosphate (NADPH), thereby inhibiting the conversion of glutathione disulfide (GSSG) to glutathione (GSH), reducing GSH concentrations in tumor cells, triggering the accumulation of ROS, and finally enhancing the effectiveness of RT.

Conclusion

Through the synergistic effect of chemotherapy and RT, NRA@DH Gel effectively inhibited the proliferation and migration of tumor cells, suppressed tumor growth, improved motor coordination, and prolonged survival in tumor-bearing mice. Our work aims to improve the NRA@DH Gel-mediated synergistic chemotherapy and RT will endow a "promising future" for the old drug in clinically comprehensive applications.

Pharmacology, Toxicology, and Rational Application of Cinnabar, Realgar, and Their Formulations

Ethnopharmacological Relevance. Mineral medicines are widely used traditional Chinese medicines with curative effects. These medicines are used for many refractory diseases. Aim of the Review. In this review, cinnabar (HgS) and realgar (As₂S₂) serve as examples of mineral medicines, and their pharmacology, therapeutic toxicity, use in traditional medicine mixtures, and research perspectives are discussed. Materials and Methods. A search was performed for the literature on cinnabar and realgar in PubMed, the Chinese Pharmacopeia, Google, and other sources. The search included studies using single herbs, traditional formulations, or novel dosage forms. Results. Cinnabar and cinnabar formulas exhibit good efficacy for sedation, sleep improvement, anxiety alleviation, and brain protection. However, previous studies on neurotransmitters have reached different conclusions, and detailed pharmacological mechanisms are lacking. Realgar and its formulas exert promising antitumor activity through regulation of cell cycle arrest, intrinsic and extrinsic apoptosis, induction of differentiation, autophagy, metabolic reprogramming, matrix metalloproteinase-9 (MMP-9) signaling, and reactive oxygen species (ROS) generation. In addition, realgar can be used to treat a variety of refractory diseases by regulating immunity and exerting antibacterial, antiviral, and other effects. However, the existing pharmacological research on the use of realgar for epidemic prevention is insufficient, and animal experiments and research at the cellular level are lacking. Inappropriate applications of cinnabar and realgar can cause toxicity, including neurotoxicity, liver toxicity, kidney toxicity, and genotoxicity. The toxicological mechanism is complex, and molecular-level research is limited. For clinical applications, theory and clinical experience must be combined to guide scientific and rational drug use and to achieve reduced toxicity and increased efficacy through the use of modern preparation methods or combined drugs. Notably, when cinnabar and realgar are used to treat targeted diseases, these agents have a bidirectional effect of “treatment” and “toxicity” on the central nervous system in pathological and normal states. The pharmacological and toxicological mechanisms need to be elucidated in greater detail in the future. Overall, systematic research is needed to provide a basis for better promotion of the rational use of cinnabar and realgar in the clinic. Conclusion. Mineral medicines are multicomponent, multiactivity, and multitargeted substances. The pharmacology and mechanisms of the toxicity and action of realgar and cinnabar are extremely complex. A number of Chinese medicinal preparations of realgar and cinnabar have demonstrated unique efficacy in the treatment of refractory diseases.

Realgar Alleviated Neuroinflammation Induced by High Protein and High Calorie Diet in Rats via the Microbiota-Gut-Brain Axis

Purpose: Gastrointestinal heat retention syndrome (GHRS) often occurs in adolescents, resulting into nervous system injury. Realgar, an arsenic mineral with neuroprotective effect, has been widely used to treat GHRS. However, its mechanism of action remains unknown. Methods: A GHRS rat model was established using a high protein and high calorie diet. We performed macroscopic characterization by assessing bowel sounds, hot/cold preference, anal temperature, and fecal features. Atomic fluorescence spectroscopy was employed to evaluate brain arsenic level while hippocampal ultrastructural changes were analyzed using transmission electron microscopy. In addition, inflammatory cytokines and BBB breakdown were analyzed by western blotting, immunofluorescence assays, and immunohistochemistry staining. We also evaluated hippocampal metabolites by LC-MS while fecal microorganisms were assessed by 16S rDNA sequencing. Results: Our data showed that the high protein and high calorie diet induced GHRS. The rat model depicted decreased bowel sounds, increased fecal characteristics score, preference for low temperature zone, and increased anal temperature. In addition, there was increase in inflammatory factors IL-6, Iba-1, and NF-κB p65 as well as reduced BBB structural protein Claudin-5 and Occludin. The data also showed appearance of hippocampus metabolites disorder and fecal microbial imbalance. Realgar treatment conferred a neuroprotective effect by inhibiting GHRS-specific characteristics, neuroinflammatory response, BBB impairment, metabolites disorder, and microbial imbalance in the GHRS rat model. Conclusion: Taken together, our analysis demonstrated that realgar confers a neuroprotective effect in GHRS rats through modulation of the microbiota-gut-brain axis.

Assessment of the Effects of Organic vs. Inorganic Arsenic and Mercury in Caenorhabditis elegans

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Similar developmental delays and oxidative stress with 20x DMA relative to NaAsO2.

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Dissimilar gene expression and locomotion with organic vs. inorganic mercury.

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Dissimilar unfolded protein responses for organic vs. inorganic arsenic and mercury.

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Across phyla, methylation has opposite effects on arsenic vs. mercury toxicity.

Exposures to mercury and arsenic are known to pose significant threats to human health. Effects specific to organic vs. inorganic forms of these toxic elements are less understood however, especially for organic dimethylarsinic acid (DMA), which has recently been detected in pups of rodent dams orally exposed to inorganic sodium (meta)arsenite (NaAsO2). Caenorhabditis elegans is a small animal alternative toxicity model. To fill data gaps on the effects of DMA relative to NaAsO2, C. elegans were exposed to these two compounds alongside more thoroughly researched inorganic mercury chloride (HgCl2) and organic methylmercury chloride (meHgCl). For timing of developmental milestone acquisition in C. elegans, meHgCl was 2 to 4-fold more toxic than HgCl2, and NaAsO2 was 20-fold more toxic than DMA, ranking the four compounds meHgCl > HgCl2 > NaAsO2 ≫ DMA for developmental toxicity. Methylmercury induced significant decreases in population locomotor activity levels in developing C. elegans. DMA was also associated with developmental hypoactivity, but at >100-fold higher concentrations than meHgCl. Transcriptional alterations in native genes were observed in wild type C. elegans adults exposed to concentrations equitoxic for developmental delay in juveniles. Both forms of arsenic induced genes involved in immune defense and oxidative stress response, while the two mercury species induced proportionally more genes involved in transcriptional regulation. A transgenic bioreporter for activation of conserved proteosome specific unfolded protein response was strongly activated by NaAsO2, but not DMA at tested concentrations. HgCl2 and meHgCl had opposite effects on a bioreporter for unfolded protein response in the endoplasmic reticulum. Presented experiments indicating low toxicity for DMA in C. elegans are consistent with human epidemiologic data correlating higher arsenic methylation capacity with resistance to arsenic toxicity. This work contributes to the understanding of the accuracy and fit-for-use categories for C. elegans toxicity screening and its usefulness to prioritize compounds of concern for further testing.

How Chinese Herbal Medicine Prevents Epidemics: From Ancient Pestilences to COVID-19 Pandemic

The ongoing coronavirus disease 2019 (COVID-19) pandemic calls for effective control and prevention. Chinese medicine (CM) has developed systematic theories and approaches for infectious disease prevention over 2000 years. Here, we review and analyze Chinese herbal medicines (CHM) used in infectious disease prevention from ancient pestilences to modern epidemics and pandemics to share cumulative preventive medical experience. A total of 829 formulas, including 329 herbs from 189 ancient books, 131 formulas with 152 herbs, and 13 Chinese patent medicines (CPM) from 30 official Chinese prevention programs used in ancient epidemics, SARS, influenza and COVID-19 prevention, were reviewed and analyzed. Preventive CHM mainly has four functions and can be taken orally or applied externally. CHM that kill pathogens (Realgar [Xionghuang], Cyrtomium Fortunei J. Sm[Guanzhong]) were commonly used externally for disinfection in ancient prevention while CHM tonifying Qi (Astragali Radix [Huangq], Glycyrrhizae Radix et Rhizoma [Gancao]) are used for modern prevention. Taking CHM that expel pathogens (Realgar [Xionghuang], Lonicerae Japonicae Flos[Jinyinhua]) and CHM eliminating dampness (Atractylodis Rhizoma [Cangzhu], Pogostemonis Herba[Guanghuoxiang]) have been commonly used from ancient times to COVID-19. Damp toxins are a common characteristic of infectious diseases such as SARS and COVID-19. Thus, taking CHM expelling damp toxins and tonifying Qi are the main methods for SARS and COVID-19 prevention. CHM with different approaches have been widely used in infectious disease prevention from ancient times to the present. Multiple CM prevention methods may provide new perspectives for future pandemics.