Anti-inflammatory activity and underlying mechanism against sepsis-induced acute lung injury of a low-molecular-weight polysaccharide from the root of Stemona tuberosa Lour.
International journal of biological macromolecules
The root of Stemona tuberosa Lour has been used to treat tuberculosis, scabies, and eczema. Polysaccharides are among its main bioactive ingredients. A low-molecular-weight (1819 Da) polysaccharide (SPS2-A) was obtained from the root of S. tuberosa Lour by optimizing three-phase partitioning, purified using an ion chromatography column, and its effects and mechanisms were investigated. Structural analysis revealed that SPS2-A contained arabinose, galactose (Gal), glucose (Glc), xylose, and mannose. The SPS2-A backbone structure comprised sugar residues →4)-α-D-Glcp-(1→, →4)-α-D-Galp-(1→, and →4,6)-β-D-Galp-(1→, while the side chain primarily comprised α-D-Glcp-(1 → connected to the O-6 position of the residue →4,6)-β-D-Galp-(1→. In vitro, SPS2-A downregulated the expression of interleukin-6 in lipopolysaccharide-induced RAW264.7 macrophages. In vivo, SPS2-A significantly downregulated the expression of myeloperoxidase, interleukin-6, interleukin-1β, and tumor necrosis factor-α in bronchoalveolar lavage fluid and lung tissue. Western blotting analysis indicated that SPS2-A reduced lung inflammation in mice with sepsis-induced acute lung injury by activating the nuclear factor κB pathway. These results suggest that SPS2-A is a potential anti-inflammatory candidate for the treatment of sepsis-induced acute lung injury.
10.1016/j.ijbiomac.2024.136617
Stem cells in sepsis and acute lung injury.
Cribbs Sushma K,Matthay Michael A,Martin Greg S
Critical care medicine
OBJECTIVE:Sepsis and acute lung injury continue to be major causes of morbidity and mortality worldwide despite advances in our understanding of pathophysiology and the discovery of new management strategies. Recent investigations show that stem cells may be beneficial as prognostic biomarkers and novel therapeutic strategies in these syndromes. This article reviews the potential use of endogenous adult tissue-derived stem cells in sepsis and acute lung injury as prognostic markers and also as exogenous cell-based therapy. DATA SOURCES:A directed systematic search of the medical literature using PubMed and OVID, with particular emphasis on the time period after 2002, was done to evaluate topics related to 1) the epidemiology and pathophysiology of sepsis and acute lung injury; and 2) the definition, characterization, and potential use of stem cells in these diseases. DATA SYNTHESIS AND FINDINGS: When available, preferential consideration was given to prospective nonrandomized clinical and preclinical studies. CONCLUSIONS:Stem cells have shown significant promise in the field of critical care both for 1) prognostic value and 2) treatment strategies. Although several recent studies have identified the potential benefit of stem cells in sepsis and acute lung injury, further investigations are needed to more completely understand stem cells and their potential prognostic and therapeutic value.
10.1097/CCM.0b013e3181f96f5f
OAS3 Deubiquitination Due to E3 Ligase TRIM21 Downregulation Promotes Epithelial Cell Apoptosis and Drives Sepsis-induced Acute Lung Injury.
International journal of biological sciences
Patients with sepsis-induced acute lung injury (SALI) show a high mortality rate, and there is no effective treatment in the clinic for SALI but only symptomatic treatment as an option. Therefore, searching for effective targets is critical for the management of SALI. Ubiquitination is an essential post-translational protein modification involved in most pathophysiological processes. However, the relationship between ubiquitination and SALI remains largely unclear. In this study, we examined the ubiquitination modification changes in SALI, identified oligoadenylate synthetase 3 (OAS3) as a key candidate accounting for SALI from integrative multi-omics analysis and confirmed its role in promoting SALI and cell apoptosis in an animal model of cecal ligation and puncture-treated mice and a cellular model of LPS-treated MLE12 cells. Mechanistically, downregulation of E3 ligase TRIM21 mediates the reduction of OAS3 K48-linked polyubiquitination at the K1079 site in lung epithelial cells of a septic model, which leads to the increase of OAS3 protein level in a proteasomal-dependent manner. The upregulated OAS3 promotes epithelial cell apoptosis through its downstream effector molecule, RNase L. In summary, these findings unveil a previously unappreciated role of OAS3 ubiquitination in SALI and offer a promising perspective for further understanding the development of sepsis and potential therapeutic target for the treatment of SALI.
10.7150/ijbs.96089
MicroRNA-1224-5p Aggravates Sepsis-Related Acute Lung Injury in Mice.
Oxidative medicine and cellular longevity
Oxidative stress and inflammation are implicated in the development of sepsis-related acute lung injury (ALI). MicroRNA-1224-5p (miR-1224-5p) plays critical roles in regulating inflammatory response and reactive oxygen species (ROS) production. The present study is aimed at investigating the role and underlying mechanisms of miR-1224-5p in sepsis-related ALI. Mice were intratracheally injected with lipopolysaccharide (LPS, 5 mg/kg) for 12 h to induce sepsis-related ALI. To manipulate miR-1224-5p level, mice were intravenously injected with the agomir, antagomir, or matched controls for 3 consecutive days. Murine peritoneal macrophages were stimulated with LPS (100 ng/mL) for 6 h to further validate the role of miR-1224-5p . To inhibit adenosine 5'-monophosphate-activated protein kinase alpha (AMPK) or peroxisome proliferator activated receptor-gamma (PPAR-), compound C or GW9662 was used and . We found that miR-1224-5p levels in lungs were elevated by LPS injection, and that the miR-1224-5p antagomir significantly alleviated LPS-induced inflammation, oxidative stress, and ALI in mice. Conversely, the miR-1224-5p agomir aggravated inflammatory response, ROS generation, and pulmonary dysfunction in LPS-treated mice. In addition, the miR-1224-5p antagomir reduced, while the miR-1224-5p agomir aggravated LPS-induced inflammation and oxidative stress in murine peritoneal macrophages. Further findings revealed that miR-1224-5p is directly bound to the 3'-untranslated regions of PPAR- and subsequently suppressed PPAR-/AMPK axis, thereby aggravating LPS-induced ALI and . We demonstrate for the first time that endogenous miR-1224-5p is a critical pathogenic factor for inflammation and oxidative damage during LPS-induced ALI through inactivating PPAR-/AMPK axis. Targeting miR-1224-5p may help to develop novel approaches to treat sepsis-related ALI.
10.1155/2022/9493710
Histone lactylation-regulated METTL3 promotes ferroptosis via m6A-modification on ACSL4 in sepsis-associated lung injury.
Redox biology
Elevated lactate levels are a significant biomarker of sepsis and are positively associated with sepsis-related mortality. Sepsis-associated lung injury (ALI) is a leading cause of poor prognosis in clinical patients. However, the underlying mechanisms of lactate's involvement in sepsis-associated ALI remain unclear. In this study, we demonstrate that lactate regulates N6-methyladenosine (m6A) modification levels by facilitating p300-mediated H3K18la binding to the METTL3 promoter site. The METTL3-mediated m6A modification is enriched in ACSL4, and its mRNA stability is regulated through a YTHDC1-dependent pathway. Furthermore, short-term lactate stimulation upregulates ACSL4, which promotes mitochondria-associated ferroptosis. Inhibition of METTL3 through knockdown or targeted inhibition effectively suppresses septic hyper-lactate-induced ferroptosis in alveolar epithelial cells and mitigates lung injury in septic mice. Our findings suggest that lactate induces ferroptosis via the GPR81/H3K18la/METTL3/ACSL4 axis in alveolar epithelial cells during sepsis-associated ALI. These results reveal a histone lactylation-driven mechanism inducing ferroptosis through METTL3-mediated m6A modification. Targeting METTL3 represents a promising therapeutic strategy for patients with sepsis-associated ALI.
10.1016/j.redox.2024.103194