Role of Heme Oxygenase-1 in Dual Stress Response of Herbicide and Micronutrient Fe in Arabidopsis thaliana

Exploring the Role of Carbon Monoxide in Seed Physiology: Implications for Stress Tolerance and Practical Uses

Carbon monoxide (CO) is recognized as a signaling molecule in plants, inducing various physiological responses. This article briefly examines the physiological functions of CO in seed biology and seedlings' responses to environmental stresses. The activity of heme oxygenase (HO), the main enzyme responsible for CO synthesis, is a key factor controlling CO levels in plant cells. CO can influence seed germination by regulating seed dormancy through interactions with genes and hormones. Additionally, CO positively affects seedling growth by enhancing the antioxidant system, thereby increasing resistance to oxidative damage caused by stress. CO has beneficial effects on root development, root length, stomatal closure, and regulation of the photosynthetic system. Its interaction with reactive oxygen species (ROS) mediates hormone- and light-dependent growth processes during the early stages of plant development under stress. Furthermore, CO interacts with other signaling molecules, such as nitric oxide (NO), molecular hydrogen (H2), and hydrogen sulfide (H2S). By gaining a better understanding of the molecular mechanisms underlying these processes, CO can be more effectively utilized to improve seed germination and seedling growth in agricultural practices.

Asiatic acid induces ferroptosis of RA-FLS via the Nrf2/HMOX1 pathway to relieve inflammation in rheumatoid arthritis

BACKGROUND

Ferroptosis is a distinct iron-dependent non-apoptotic type of programmed cell death that is implicated in the pathophysiology of rheumatoid arthritis (RA). Although asiatic acid (AA) is documented to have significant anti-inflammatory effects in various diseases, it is not known whether it can regulate RA via ferroptosis.

METHODS

The effects of AA on rheumatoid arthritis fibroid-like synoviocytes (RA-FLS) were assessed in vitro, and a rat model of type II collagen-induced arthritis (CIA) was established to evaluate the effectiveness of AA treatment in vivo.

RESULTS

AA significantly reduced both viability and colony formation in cultured RA-FLS, while increasing the levels of reactive oxygen species (ROS), ferrous iron (Fe2+), malondialdehyde (MDA), and lactate dehydrogenase (LDH), as well as the expression of COX2. Furthermore, AA induced ferroptosis in RA-FLS by promoting Fe2+ accumulation through downregulation of the expression of Keap1 and FTH1 and upregulation of Nrf2 and HMOX1. In vivo, AA treatment was found to reduce toe swelling and the arthritis score in CIA rats, as well as relieve inflammation and ankle damage and significantly upregulate the expression of Nrf2 and HMOX1 in the synovial fluid.

CONCLUSION

Treatment with AA significantly reduced the viability of RA-FLS and triggered ferroptosis by promoting accumulation of Fe2+via the Nrf2-HMOX1 pathway, and was effective in relieving inflammation in CIA model rats. These findings suggest that the use of AA may be a promising strategy for the clinical treatment of RA.

Plasma Membrane (PM) H+-ATPase Mediates Rhizosphere Acidification and Regulates Herbicide Imazethapyr Toxicity in Wheat

The plasma membrane (PM) H+-ATPase is crucial for a plant defense system. However, there is currently no consensus on whether the PM H+-ATPase plays a role in alleviating the toxic effects of herbicides on nontarget plants. We found that under the herbicide imazethapyr (IM) exposure, PM H+-ATPase activity in wheat roots increased by approximately 69.53%, leading to rhizosphere acidification. When PM H+-ATPase activity is inhibited, the toxicity of IM significantly increases: When exposed to IM alone, the total Fe content of wheat roots decreased by 29.07%, the relative Fe2+ content increased by 27.75%, and the ROS content increased by 27.74%. When the PM H+-ATPase activity was inhibited, the corresponding data under IM exposure were 37.36%, 215%, and 57.68%, respectively. This work delves into the role of PM H+-ATPase in mediating the detoxification mechanism in plants exposed to herbicides, offering new insights into enhancing crop resistance against herbicides.

Carbon monoxide/heme oxygenase system in plant: Roles in abiotic stress response and crosstalk with other signals molecules

Carbon monoxide (CO) has been recognized as a crucial gasotransmitter mainly produced by heme oxygenase (HO)-catalyzed heme degradation in plant. Recent studies have shown that CO plays an important role in regulating growth and development of plant, as well as and responding to a variety of abiotic stresses. Meanwhile, many studies have reported on CO working in combination with other signal molecules to mitigate abiotic stress. Here, we presented a comprehensive overview of recent developments in which CO reduces plant damage caused by abiotic stresses. The regulation of antioxidant system, photosynthetic system, ion balance and transport are the main mechanisms of CO-alleviated abiotic stress. We also proposed and discussed the relationship between CO and other signal molecules, including nitric oxide (NO), hydrogen sulfide (H2S), hydrogen gas (H2), abscisic acid (ABA), indole 3-acetic acid (IAA), gibberellin (GA), cytokine (CTK), salicylic acid (SA), jasmonic acid (JA), hydrogen peroxide (H2O2) and calcium ion (Ca2+). Furthermore, the important role of HO genes in alleviating abiotic stress was also discussed. We proposed promising and new research directions for the study of plant CO, which can provide further insights on the role of CO in plant growth and development under abiotic stress.