The Role of Histone Deacetylases in Acute Lung Injury-Friend or Foe.

Acute lung injury (ALI), caused by intrapulmonary or extrapulmonary factors such as pneumonia, shock, and sepsis, eventually disrupts the alveolar-capillary barrier, resulting in diffuse pulmonary oedema and microatasis, manifested by refractory hypoxemia, and respiratory distress. Not only is ALI highly lethal, but even if a patient survives, there are also multiple sequelae. Currently, there is no better treatment than supportive care, and we urgently need to find new targets to improve ALI. Histone deacetylases (HDACs) are epigenetically important enzymes that, together with histone acetylases (HATs), regulate the acetylation levels of histones and non-histones. While HDAC inhibitors (HDACis) play a therapeutic role in cancer, inflammatory, and neurodegenerative diseases, there is also a large body of evidence suggesting the potential of HDACs as therapeutic targets in ALI. This review explores the unique mechanisms of HDACs in different cell types of ALI, including macrophages, pulmonary vascular endothelial cells (VECs), alveolar epithelial cells (AECs), and neutrophils.

Single cell meta-analysis of EndMT and EMT state in COVID-19.

COVID-19 prognoses suggests that a proportion of patients develop fibrosis, but there is no evidence to indicate whether patients have progression of mesenchymal transition (MT) in the lungs. The role of MT during the COVID-19 pandemic remains poorly understood. Using single-cell RNA sequencing, we profiled the transcriptomes of cells from the lungs of healthy individuals (n = 45), COVID-19 patients (n = 58), and idiopathic pulmonary fibrosis (IPF) patients (n = 64) human lungs to map the entire MT change. This analysis enabled us to map all high-resolution matrix-producing cells and identify distinct subpopulations of endothelial cells (ECs) and epithelial cells as the primary cellular sources of MT clusters during COVID-19. For the first time, we have identied early and late subgroups of endothelial mesenchymal transition (EndMT) and epithelial-mesenchymal transition (EMT) using analysis of public databases for single-cell sequencing. We assessed epithelial subgroups by age, smoking status, and gender, and the data suggest that the proportional changes in EMT in COVID-19 are statistically significant. Further enumeration of early and late EMT suggests a correlation between invasive genes and COVID-19. Finally, EndMT is upregulated in COVID-19 patients and enriched for more inflammatory cytokines. Further, by classifying EndMT as early or late stages, we found that early EndMT was positively correlated with entry factors but this was not true for late EndMT. Exploring the MT state of may help to mitigate the fibrosis impact of SARS-CoV-2 infection.

A review of fibroblast-like synoviocytes in the pathogenesis of Rheumatoid arthritis: Their activation and the inhibition of their apoptosis

Rheumatoid Arthritis (RA) is a systemic, autoimmune, inflammatory disease characterized by synovial hyperplasia, inflammatory cell infiltration in the synovial tissues, and progressive destruction of cartilage and bones. This disease often leads to chronic disability. More recently, activation of synovial fibroblasts (SFs) has been linked to innate immune responses and several cellular signalingpathways that ultimately result in the aggressive and invasive stages of RA. SFs are the major sources of pro-inflammatory cytokines in RA synovium. They participate in maintaining the inflammatory state that leads to synovial hyperplasia and angiogenesis in the inflamed synovium. The altered apoptotic response of synovial and inflammatory cells has been connected to these alterations of inflamed synovium. RA synovial fibroblasts (RASFs) have the ability to inhibit several apoptotic proteins that cause their abnormal proliferation. This proliferation leads to synovial hyperplasia. Apoptotic pathway proteins have thus been identified as possible targets for modifying the pathophysiology of RA. This review summarizes current knowledge of SF activation and its roles in the inhibition of apoptosis in the synovium, which is involved in joint damage during the effector phase of RA development.Copyright © 2022 Biomedpress.

Developing advanced cell culture models to study COVID19-associated pulmonary fibrosis

Patients with severe COVID-19-associated pneumonia are at risk to develop pulmonary fibrosis. To study the underlying mechanisms, we aim to develop advanced cell culture models that reliably reflect COVID-19-related profibrotic microenvironment. To identify key cellular players, we performed pilot immunohistochemistry analysis on lung tissue from COVID-19 patients with fibrosis collected during autopsy. Results revealed diffuse alveolar damage with macrophage infiltration, and myofibroblast accumulation with enriched collagen deposition surrounding the damaged alveoli. To mimic SARS-CoV-2 infection in alveoli, we infected human primary type II alveolar epithelial cells (AEC2) and found enhanced signaling of profibrotic cytokine transforming growth factor beta (TGFbeta) in some donors. To recreate the early fibrotic niche, an alveolar-macrophage-fibroblast (AMF) tri-culture model was established. After infecting AEC2 with SARS-CoV-2 in this AMF model, gene expression analysis provided evidence for fibroblast-to-myofibroblast transition. Furthermore, we found that overexpression of SARS-CoV-2 papain-like protease (PLpro) can promote TGFbeta signaling in HEK293T and A549 cells. After infecting AEC2 with SARS-CoV-2 PLpro lentivirus in the AMF model, we found signs of epithelial-to-mesenchymal transition and fibroblast-to myofibroblast transition. In future studies, we will use a detailed analysis of COVID-19-associated lung fibrosis with other types of lung fibrosis, to further refine COVID-19-related fibrosis models, including lung-on-chip models.

Quercetin potentially suppresses renal fibrosis in patients with COVID-19 under hypoxic state

Introduction: Renal fibrosis is a main outcome of acute kidney injury in COVID-19 survivors, which is emerging as a global public health concern. Lung damage in the COVID-19 patients leads to acute and chronic hypoxia, which results in inflammation, epithelial-mesenchymal transformation, and fibrosis in kidney. Quercetin is an abundant flavonoid in plant materials. Previous studies indicate that quercetin alleviates the decline of renal function, suppress epithelial to mesenchymal transformation in renal tubules, and reduce fibrosis. The study aimed to explore potential targets of quercetin on treating renal fibrosis in patients with COVID-19-induced hoxpia. Method(s): Gene/protein targets related to COVID-19, renal fibrosis, or quercetin were searched from ten databases, and Cytoscape 3.8.2 was then used to construct the protein-protein interaction network and to identify the core targets. The Metascape platform was used for bioconcentration analysis, while AutoDock Vina was used as the primary molecular docking tool. In vitro, the combination model of hypoxia- and transforming growth factor-beta (TGF-beta)- treated human proximal tubule epithelial cells (HK2 cells) was applied to determine the reno-protective effect of quercetin. Result(s): The network analysis showed that quercetin targeted on TGF-beta pathway in treating COVID-19 induced renal fibrosis. In the intersection PPI network, 115 targets were obtained, and gene enrichment analysis was conducted on 109 key nodes. Molecular docking analysis revealed that quercetin could spontaneously bind to eight targets on the TGF-beta pathway, and the binding energy of TGF-beta1 was 29.82 kJ/mol. The in vitro experiment further showed that quercetin significantly suppressed fibrosis in TGF-beta and hypoxia treated HK2 cells in a dose dependent manner by inhibiting TGF-beta/Smad3 pathway. Conclusion(s): Quercetin could attenuate renal fibrosis in patients with COVID-19 by suppressing TGF-beta/Smad3 pathway. No conflict of interestCopyright © 2023

74th Annual Congress of the Japan Society of Obstetrics and Gynecology

The proceedings contain 429 papers. The topics discussed include: a short peptide encoded by long non-coding RNA small nucleolar RNA host gene 6 promotes cell migration and epithelial-mesenchymal transition by activating transforming growth factor-beta/SMAD signaling pathway in human endometrial cells;a short peptide encoded by long non-coding rna small nucleolar rna host gene 6 promotes cell migration and epithelial-mesenchymal transition by activating transforming growth factor-beta/smad signaling pathway in human endometrial cells;compatible cut-off values for luteinizing hormone and the luteinizing hormone/follicle-stimulating hormone ratio in diagnostic criteria of the Japan society of obstetrics and gynecology for polycystic ovary syndrome;intracytoplasmic sperm injection cycle success in patients under 35 years old with diminished ovarian reserve plus severe male factor;assisted reproductive technology and neonatal intensive care unit: a retrospective observational study from a single center;the value of clinical symptoms, the neutrophil-to-lymphocyte ratio, and ultrasonographic features in predicting adnexal torsion: a case-control study;construction of a diagnostic classifier for cervical intraepithelial neoplasia and cervical cancer based on xgboost feature selection and random forest model;and impact of the COVID-19 pandemic on surgery for benign diseases in gynecology: a nationwide survey by the japan society of obstetrics and gynecology.

Identification and vitro verification of the potential drug targets of active ingredients of Chonglou in the treatment of lung adenocarcinoma based on EMT-related genes.

Lung adenocarcinoma (LUAD) is the main histological type of lung cancer with an unfavorable survival rate. Metastasis is the leading LUAD-related death with Epithelial-Mesenchymal Transition (EMT) playing an essential role. The anticancer efficacies of the active ingredients in Chonglou have been widely reported in various cancers. However, the potential therapeutic targets of the Chonglou active ingredients in LUAD patients remain unknown. Here, the network pharmacology and bioinformatics were performed to analyze the associations of the clinical characteristics, immune infiltration factors and m6A-related genes with the EMT-related genes associated with LUAD (EMT-LUAD related genes), and the molecular docking, STRING, GO, and KEGG enrichment for the drug targets of Chonglou active ingredients associated with EMT (EMT-LUAD-Chonglou related genes). And, cell viability analysis and cell invasion and infiltration analysis were used to confirm the theoretical basis of this study. A total of 166 EMT-LUAD related genes were identified and a multivariate Cox proportional hazards regression model with a favorable predictive accuracy was constructed. Meanwhile, the immune cell infiltration, immune cell subsets, checkpoint inhibitors and the expression of m6A-related genes were significantly associated with the risk scores for EMT-LUAD related genes with independent significant prognostic value of all included LUAD patients. Furthermore, 12 EMT-LUAD-Chonglou related genes with five core drug targets were identified, which participated in LUAD development through extracellular matrix disassembly, collagen metabolic process, collagen catabolic process, extracellular matrix organization, extracellular structure organization and inflammatory response. Moreover, we found that the active ingredients of Chonglou could indeed inhibit the progression of lung adenocarcinoma cells. These results are oriented towards EMT-related genes to achieve a better understanding of the role of Chonglou and its targets in osteosarcoma development and metastasis, thus guiding future preclinical studies and facilitating clinical translation of LUAD treatment.

Lung fibrosis: Post-COVID-19 complications and evidences.

BACKGROUND: COVID 19, a lethal viral outbreak that devastated lives and the economy across the globe witnessed non-compensable respiratory illnesses in patients. As been evaluated in reports, patients receiving long-term treatment are more prone to acquire Pulmonary Fibrosis (PF). Repetitive damage and repair of alveolar tissues increase oxidative stress, inflammation and elevated production of fibrotic proteins ultimately disrupting normal lung physiology skewing the balance towards the fibrotic milieu. AIM: In the present work, we have discussed several important pathways which are involved in post-COVID PF. Further, we have also highlighted the rationale for the use of antifibrotic agents for post-COVID PF to decrease the burden and improve pulmonary functions in COVID-19 patients. CONCLUSION: Based on the available literature and recent incidences, it is crucial to monitor COVID-19 patients over a period of time to rule out the possibility of residual effects. There is a need for concrete evidence to deeply understand the mechanisms responsible for PF in COVID-19 patients.

The Effects of Swine Coronaviruses on ER Stress, Autophagy, Apoptosis, and Alterations in Cell Morphology.

Swine coronaviruses include the following six members, namely porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine delta coronavirus (PDCoV), swine acute diarrhea syndrome coronavirus (SADS-CoV), porcine hemagglutinating encephalomyelitis virus (PHEV), and porcine respiratory coronavirus (PRCV). Clinically, PEDV, TGEV, PDCoV, and SADS-CoV cause enteritis, whereas PHEV induces encephalomyelitis, and PRCV causes respiratory disease. Years of studies reveal that swine coronaviruses replicate in the cellular cytoplasm exerting a wide variety of effects on cells. Some of these effects are particularly pertinent to cell pathology, including endoplasmic reticulum (ER) stress, unfolded protein response (UPR), autophagy, and apoptosis. In addition, swine coronaviruses are able to induce cellular changes, such as cytoskeletal rearrangement, alterations of junctional complexes, and epithelial-mesenchymal transition (EMT), that render enterocytes unable to absorb nutrients normally, resulting in the loss of water, ions, and protein into the intestinal lumen. This review aims to describe the cellular changes in swine coronavirus-infected cells and to aid in understanding the pathogenesis of swine coronavirus infections. This review also explores how the virus exerted subcellular and molecular changes culminating in the clinical and pathological findings observed in the field.

ZAP isoforms regulate unfolded protein response and epithelial- mesenchymal transition.

Human ZAP inhibits many viruses, including HIV and coronaviruses, by binding to viral RNAs to promote their degradation and/or translation suppression. However, the regulatory role of ZAP in host mRNAs is largely unknown. Two major alternatively spliced ZAP isoforms, the constitutively expressed ZAPL and the infection-inducible ZAPS, play overlapping yet different antiviral and other roles that need further characterization. We found that the splicing factors hnRNPA1/A2, PTBP1/2, and U1-snRNP inhibit ZAPS production and demonstrated the feasibility to modulate the ZAPL/S balance by splice-switching antisense oligonucleotides in human cells. Transcriptomic analysis of ZAP-isoform-specific knockout cells revealed uncharacterized host mRNAs targeted by ZAPL/S with broad cellular functions such as unfolded protein response (UPR), epithelial-mesenchymal transition (EMT), and innate immunity. We established that endogenous ZAPL and ZAPS localize to membrane compartments and cytosol, respectively, and that the differential localization correlates with their target-RNA specificity. We showed that the ZAP isoforms regulated different UPR branches under resting and stress conditions and affected cell viability during ER stress. We also provided evidence for a different function of the ZAP isoforms in EMT-related cell migration, with effects that are cell-type dependent. Overall, this study demonstrates that the competition between splicing and IPA is a potential target for the modulation of the ZAPL/S balance, and reports new cellular transcripts and processes regulated by the ZAP isoforms.

Di-(2-ethylhexyl) Phthalate Triggers Proliferation, Migration, Stemness, and Epithelial-Mesenchymal Transition in Human Endometrial and Endometriotic Epithelial Cells via the Transforming Growth Factor-ß/Smad Signaling Pathway.

Di-(2-ethylhexyl) phthalate (DEHP) is a frequently used plasticizer that may be linked to the development of endometriosis, a common gynecological disorder with a profound impact on quality of life. Despite its prevalence, vital access to treatment has often been hampered by a lack of understanding of its pathogenesis as well as reliable disease models. Recently, epithelial-mesenchymal transition (EMT) has been suggested to have a significant role in endometriosis pathophysiology. In this study, we found that DEHP treatment enhanced proliferation, migration, and inflammatory responses, along with EMT and stemness induction in human endometrial and endometriotic cells. The selective transforming growth factor-ß (TGF-ß) receptor type 1/2 inhibitor LY2109761 reversed the DEHP-induced cell proliferation and migration enhancement as well as the increased expression of crucial molecules involved in inflammation, EMT, and stemness, indicating that DEHP-triggered phenomena occur via the TGF-ß/Smad signaling pathway. Our study clearly defines the role of DEHP in the etiology and pathophysiological mechanisms of endometriosis and establishes an efficient disease model for endometriosis using a biomimetic 3D cell culture technique. Altogether, our data provide novel etiological and mechanistic insights into the role of DEHP in endometriosis pathogenesis, opening avenues for developing novel preventive and therapeutic strategies for endometriosis.

Frequency of the Risk A Allele of rs17713054 Localized in the 3p21.31 COVID-19 Risk Locus in the Yakut Population

Background: Genome-wide association studies identified the region of chromosome 3p21.31 as having the strongest association with the severe COVID-19 and susceptibility to SARS-CoV-2 infection. The aim of our study was to investigate the frequency of the risk A allele of rs17713054 localized in the 3p21.31 COVID-19 risk locus in Yakuts. Methods and Results: A total of 382 DNA samples from healthy Yakut volunteers (184 men and 198 women;the average age of 41.8±0.05 years) were examined. Our results show that the frequency of the risk A allele of the rs17713054 SNP in the Yakut population occurs at a frequency of 2% and generally corresponds to the frequency of East Asian populations (from 0% to 2%), geographically close to the Yakuts and belonging to the same Mongoloid race. © 2022, International Medical Research and Development Corporation. All rights reserved.

Targeting Metabolic Reprograming for the Prevention and Treatment of Proliferative Vitreoretinopathy

This is our first year on the project and we report that we have identified key metabolic reprogramming traits associated with proliferative vitreoretinopathy using our in-vitro model of epithelial-mesenchymal transition (EMT) of human retinal pigment epithelial cells (RPE). We have obtained IACUC and ACURO approval for our in-vivo rabbit model and completed training on rabbit handling and rabbit ocular surgery. We have also obtained IRB and HRPO approval for metabolomics analysis of human vitreous and sample collection is currently underway with samples scheduled for collection in the coming weeks. We have completed metabolomics analysis for our TGF-treated ARPE-19, revealing novel insights into metabolic pathway rewiring during EMT of RPE. We have begun testing the efficacy of metabolic drugs in blocking the TGF activity in ARPE-19. While we had a productive start toour grant in 2019, our progress has been hindered in 2020 due to a period of lab shut-down and restrictions on collection of human samples due to the COVID-19 pandemic.

Vimentin and its role as a biomarker in health and disease

Vimentin is an intermediate filament protein responsible for maintaining cellular integrity and resistance to stress. It has a widespread distribution in many cells throughout the body where it forms a cytoskeletal framework. Vimentin plays an important role in the regulation of many cellular and tissue functions. It is overexpressed in malignancies, potentially malignant oral disorders and autoimmune conditions like rheumatoid arthritis and Crohn’s disease. It is associated with cell surface binding and replication of viruses such as human immunodeficiency virus (HIV), severe acute respiratory syndrome-related Coronavirus, dengue and encephalitis. In HIV, it is associated with the viral infectivity factor which is associated with HIV replication. It can be used as a biomarker for diagnosis and prognosis and has potential as a therapeutic target in many conditions. The present review focuses on the structure, functions, clinical implications and future scope of vimentin in the management of various diseases.

Network Pharmacology and Experimental Assessment to Explore the Pharmacological Mechanism of Qimai Feiluoping Decoction Against Pulmonary Fibrosis.

Pulmonary fibrosis (PF) is one of the pathologic changes in COVID-19 patients in convalescence, and it is also a potential long-term sequela in severe COVID-19 patients. Qimai Feiluoping decoction (QM) is a traditional Chinese medicine formula recommended in the Chinese national medical program for COVID-19 convalescent patients, and PF is one of its indications. Through clinical observation, QM was found to improve the clinical symptoms and pulmonary function and reduce the degree of PF of COVID-19 convalescent patients. To further explore the pharmacological mechanisms and possible active components of QM in anti-PF effect, UHPLC/Q-TOF-MS was used to analyze the composition of the QM extract and the active components that can be absorbed into the blood, leading to the identification of 56 chemical compounds and 10 active components. Then, network pharmacology was used to predict the potential mechanisms and targets of QM; it predicted that QM exerts its anti-PF effects via the regulation of the epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) degradation, and TGF-ß signaling pathway. Finally, TGF-ß1-induced A549 cells were used to verify and explore the pharmacological effects of QM and found that QM could inhibit the proliferation of TGF-ß1-induced A549 cells, attenuate EMT, and promote ECM degradation by inhibiting the TGF-ß/Smad3 pathway.

An Integrated View of Virus-Triggered Cellular Plasticity Using Boolean Networks.

Virus-related mortality and morbidity are due to cell/tissue damage caused by replicative pressure and resource exhaustion, e.g., HBV or HIV; exaggerated immune responses, e.g., SARS-CoV-2; and cancer, e.g., EBV or HPV. In this context, oncogenic and other types of viruses drive genetic and epigenetic changes that expand the tumorigenic program, including modifications to the ability of cancer cells to migrate. The best-characterized group of changes is collectively known as the epithelial-mesenchymal transition, or EMT. This is a complex phenomenon classically described using biochemistry, cell biology and genetics. However, these methods require enormous, often slow, efforts to identify and validate novel therapeutic targets. Systems biology can complement and accelerate discoveries in this field. One example of such an approach is Boolean networks, which make complex biological problems tractable by modeling data ("nodes") connected by logical operators. Here, we focus on virus-induced cellular plasticity and cell reprogramming in mammals, and how Boolean networks could provide novel insights into the ability of some viruses to trigger uncontrolled cell proliferation and EMT, two key hallmarks of cancer.

Low molecular weight fucoidan attenuating pulmonary fibrosis by relieving inflammatory reaction and progression of epithelial-mesenchymal transition.

Diffuse alveolar injury and pulmonary fibrosis (PF) are the main causes of death of Covid-19 cases. In this study a low molecular weight fucoidan (LMWF) with unique structural was obtained from Laminaria japonica, and its anti- PF and anti-epithelial-mesenchymal transition (EMT) bioactivity were investigated both in vivo and in vitro. After LWMF treatment the fibrosis and inflammatory factors stimulated by Bleomycin (BLM) were in lung tissue. Immunohistochemical and Western-blot results found the expression of COL2A1, ß-catenin, TGF-ß, TNF-α and IL-6 were declined in mice lung tissue. Besides, the phosphorylation of PI3K and Akt were inhibited by LMWF. In addition, the progression of EMT induced by TGF-ß1 was inhibited by LMWF through down-regulated both TGF-ß/Smad and PI3K/AKT signaling pathways. These data indicate that unique LMWF can protect the lung from fibrosis by weakening the process of inflammation and EMT, and it is a promising therapeutic option for the treatment of PF.

Neutrophil Extracellular Traps Induce the Epithelial-Mesenchymal Transition: Implications in Post-COVID-19 Fibrosis.

The release of neutrophil extracellular traps (NETs), a process termed NETosis, avoids pathogen spread but may cause tissue injury. NETs have been found in severe COVID-19 patients, but their role in disease development is still unknown. The aim of this study is to assess the capacity of NETs to drive epithelial-mesenchymal transition (EMT) of lung epithelial cells and to analyze the involvement of NETs in COVID-19. Bronchoalveolar lavage fluid of severe COVID-19 patients showed high concentration of NETs that correlates with neutrophils count; moreover, the analysis of lung tissues of COVID-19 deceased patients showed a subset of alveolar reactive pneumocytes with a co-expression of epithelial marker and a mesenchymal marker, confirming the induction of EMT mechanism after severe SARS-CoV2 infection. By airway in vitro models, cultivating A549 or 16HBE at air-liquid interface, adding alveolar macrophages (AM), neutrophils and SARS-CoV2, we demonstrated that to trigger a complete EMT expression pattern are necessary the induction of NETosis by SARS-CoV2 and the secretion of AM factors (TGF-ß, IL8 and IL1ß). All our results highlight the possible mechanism that can induce lung fibrosis after SARS-CoV2 infection.

Epithelial-mesenchymal transition of absorptive enterocytes and depletion of Peyer's patch M cells after PEDV infection.

This study focused on intestinal restitution including phenotype switching of absorptive enterocytes and the abundance of different enterocyte subtypes in weaned pigs after porcine epidemic diarrhea virus (PEDV) infection. At 10 days post-PEDV-inoculation, the ratio of villus height to crypt depth in both jejunum and ileum had restored, and the PEDV antigen was not detectable. However, enterocytes at the villus tips revealed epithelial-mesenchymal transition (EMT) in the jejunum in which E-cadherin expression decreased while expression of N-cadherin, vimentin, and Snail increased. Additionally, there was reduced expression of actin in microvilli and Zonula occludens-1 (ZO-1) in tight junctions. Moreover, the protein concentration of transforming growth factor ß1 (TGFß1), which mediates EMT and cytoskeleton alteration, was increased. We also found a decreased number of Peyer's patch M cells in the ileum. These results reveal incomplete restitution of enterocytes in the jejunum and potentially impaired immune surveillance in the ileum after PEDV infection.

Natural products as LSD1 inhibitors for cancer therapy.

Natural products generally fall into the biologically relevant chemical space and always possess novel biological activities, thus making them a rich source of lead compounds for new drug discovery. With the recent technological advances, natural product-based drug discovery is now reaching a new era. Natural products have also shown promise in epigenetic drug discovery, some of them have advanced into clinical trials or are presently being used in clinic. The histone lysine specific demethylase 1 (LSD1), an important class of histone demethylases, has fundamental roles in the development of various pathological conditions. Targeting LSD1 has been recognized as a promising therapeutic option for cancer treatment. Notably, some natural products with different chemotypes including protoberberine alkaloids, flavones, polyphenols, and cyclic peptides have shown effectiveness against LSD1. These natural products provide novel scaffolds for developing new LSD1 inhibitors. In this review, we mainly discuss the identification of natural LSD1 inhibitors, analysis of the co-crystal structures of LSD1/natural product complex, antitumor activity and their modes of action. We also briefly discuss the challenges faced in this field. We believe this review will provide a landscape of natural LSD1 inhibitors.