Estrogen activates pyruvate kinase M2 and increases the growth of TSC2-deficient cells

Omics research in lymphangioleiomyomatosis: status and challenges

INTRODUCTION

Lymphangioleiomyomatosis (LAM) is a rare and progressive disorder that usually arises in the lung and almost exclusively affects women of childbearing age. In recent years, a number of molecules have been shown to be differentially expressed between patients with LAM and healthy control individuals, and some of these molecules, in addition to vascular endothelial growth factor D (VEGF-D), have the potential to be novel biomarkers.

AREAS COVERED

This review summarizes the recent advances in omics research, including genomics, transcriptomics, proteomics, and metabolomics, in LAM biomarker discovery. It also retrieves the literature on LAM biomarkers studied by omics techniques in the last ten years using PubMed and other retrieval tools.

EXPERT OPINION

Further research on expanded sample sizes can be conducted to construct specific models to study the role of these molecules in the pathogenesis of LAM and clarify the underlying mechanisms involved. In the future, in terms of technology, the combination of various omics methods is expected to result in novel biomarker discovery.

Novel developments in the study of estrogen in the pathogenesis and therapeutic intervention of lymphangioleiomyomatosis

OBJECTIVE

This study aimed to enhance the understanding of the role of estrogen in lymphangioleiomyomatosis(LAM) and to conclude the impact of estrogen-altering events on the condition and recent advances in estrogen-based treatments for LAM.

RESULTS

LAM development is strongly linked to mutations in the tuberous sclerosis gene (TSC1/2) and the presence of estrogen. Estrogen plays a significant role in the spread of TSC2-deficient uterine leiomyoma cells to the lungs and the production of pulmonary LAM. Menstruation, pregnancy, estrogen medication, and other events that cause an increase in estrogen levels can trigger the disorder, leading to a sudden worsening of symptoms. Current findings do not support using estrogen-blocking therapy regimens. However, Faslodex, which is an estrogen receptor antagonist, presents new possibilities for future therapeutic approaches in LAM.

CONCLUSION

Estrogen is crucial in the development and spread of LAM. The use of estrogen inhibitors or estrogen receptor antagonists alone does not provide good control of the disease or even poses a greater risk, and the use of a combination of mTOR receptor inhibitors, complete estrogen receptor antagonists, estrogen inhibitors, and autophagy inhibitors targeting important signaling pathways in LAM pathogenesis may be of greater benefit to the patient.

Small-molecule targeting PKM2 provides a molecular basis of lactylation-dependent fibroblast-like synoviocytes proliferation inhibition against rheumatoid arthritis

Fibroblast-like synoviocytes (FLS) play an important role in rheumatoid arthritis (RA)-related swelling and bone damage. Therefore, novel targets for RA therapy in FLS are urgently discovered for improving pathologic phenomenon, especially joint damage and dyskinesia. Here, we suggested that pyruvate kinase M2 (PKM2) in FLS represented a pharmacological target for RA treatment by antimalarial drug artemisinin (ART). We demonstrated that ART selectively inhibited human RA-FLS and rat collagen-induced arthritis (CIA)-FLS proliferation and migration without observed toxic effects. In particular, the identification of targets revealed that PKM2 played a crucial role as a primary regulator of the cell cycle, leading to the heightened proliferation of RA-FLS. ART exhibited a direct interaction with PKM2, resulting in an allosteric modulation that enhances the lactylation modification of PKM2. This interaction further promoted the binding of p300, ultimately preventing the nuclear translocation of PKM2 and inducing cell cycle arrest at the S phase. In vivo, ART obviously suppressed RA-mediated synovial hyperplasia, bone damage and inflammatory response to further improve motor behavior in CIA-rats. Taken together, these findings indicate that directing interventions towards PKM2 in FLS could offer a hopeful avenue for pharmaceutical treatments of RA through the regulation of cell cycle via PKM2 lactylation.

Kidney transplantation in patients with tuberous sclerosis complex

BACKGROUND

Tuberous sclerosis complex (TSC) is a disorder of the mammalian target of the rapamycin (mTOR) pathway associated with the development of multisystem tumors, including renal angiomyolipoma (AML). These renal tumors are benign by nature but locally invasive and carry a risk for the progression of chronic kidney disease (CKD) to end stage kidney disease (ESKD). The frequency of subsequent renal transplantation in this population is largely uncharacterized, although single-center data suggests that 5%-15% of adult TSC patients are kidney transplant recipients.

METHODS

This retrospective cohort study utilized United Network for Organ Sharing (UNOS) data. We included candidates waitlisted between 1987 and 2020 for a first kidney transplant with TSC-associated kidney failure. We utilized descriptive statistics to characterize the frequency of first-time kidney transplant waitlisting and transplantation among persons with TSC and the Fine-Gray subdistribution hazard model to evaluate characteristics associated with progression from waitlist.

RESULTS

We identified 200 TSC-associated kidney failure patients within the waitlist cohort. Of these, 12 were pediatric patients. Two-thirds (N = 134) of waitlisted persons were female. One hundred forty patients received a transplant with a median waitlist time of 2 years. Younger age at waitlisting was associated with a greater probability of progressing to transplant (HR 0.98 [95% CI: 0.96-0.99]). 91.8% of kidney transplant recipients survived 1-year post-transplant with a functioning allograft.

CONCLUSIONS

The majority of patients with TSC who are waitlisted for a kidney transplant progress onto transplantation with excellent 1-year post transplant patient and allograft survival.

Lymphangioleiomyomatosis and pregnancy: a mini-review

Lymphangioleiomyomatosis(LAM) is a slow progressive, rare cystic lung disease in women of reproductive age, associated with infiltration of the lung by atypical smooth muscle like cells, leading to the cystic destruction of the lung parenchyma. As LAM exclusively affects women of childbearing age, it can arise or exacerbate during pregnancy. Many patients with LAM are discouraged from pregnancy, although there is not much objective evidence effect on fertility. Patients diagnosed with LAM during pregnancy experience worse outcomes, so the safety of pregnancy is a vexing problem. What was worse, treatment strategies are limited on the effects of LAM on pregnancy outcomes. Pregnancy could be considered in LAM patients. Successful delivery in women with LAM depends on the condition of the LAM, which is in turn dependent on obstetricians and respiratory physicians. In this review, we describe the epidemiology, pathogenesis, diagnosis, clinical features and the treatment strategies of LAM during pregnancy.

Multidisciplinary Outpatient Clinic of Neurocutaneous Diseases: Five-year Experience of a Pediatric Tertiary Hospital in Portugal

INTRODUCTION

Neurocutaneous syndromes (NCS) are a heterogeneous group of conditions with multiorgan involvement and diverse manifestations, evolving throughout life with significant morbidity. A multidisciplinary approach to NCS patients has been advocated, although a specific model is not yet established. The aim of this study was 1) to describe the organization of the recently created Multidisciplinary Outpatient Clinic of Neurocutaneous Diseases (MOCND) at a Portuguese pediatric tertiary hospital; 2) to share our institutional experience focusing on the most common conditions, neurofibromatosis type 1 (NF1) and tuberous sclerosis complex (TSC); 3) to analyze the advantages of a multidisciplinary center and approach in NCS.

METHODS

Retrospective analysis of 281 patients enrolled in the MOCND over the first five years of activity (October 2016 to December 2021), reviewing genetics, family history, clinical features, complications, and therapeutic strategies for NF1 and TSC.

RESULTS

The clinic works weekly with a core team of pediatricians and pediatric neurologists supported by other specialties as needed. Of the 281 patients enrolled, 224 (79.7%) had identifiable syndromes such as NF1 (n = 105), TSC (n = 35), hypomelanosis of Ito (n = 11), Sturge-Weber syndrome (n = 5), and others. In NF1 patients, 41.0% had a positive family history, all manifested café-au-lait macules, 38.1% neurofibromas with 45.0% being large plexiform neurofibromas. Sixteen were under treatment with selumetinib. Genetic testing was performed in 82.9% of TSC patients with pathogenic variants found in TSC2 gene in 72.4% patients (82.7% if considered contiguous gene syndrome). Family history was positive in 31.4%. All TSC patients presented hypomelanotic macules and fulfilled diagnostic criteria. Fourteen patients were being treated with mTOR inhibitors.

CONCLUSION

Offering a systematic and multidisciplinary approach to NCS patients enables timely diagnosis, promotes a structured follow-up, and encourages discussion to outline management plans for optimal care to every patient, with significant impact on the quality of life of patients and families.

Identification of common genetic features and pathways involved in pulmonary lymphangioleiomyomatosis and ER-positive breast cancer

Accumulating evidence suggests that patients with pulmonary lymphangioleiomyomatosis (PLAM) have a markedly higher prevalence of breast cancer (BC) than the general population. However, the underlying pathophysiological mechanisms remain unclear. Therefore, in this study, we employed a bioinformatics approach to understand the association between PLAM and estrogen receptor (ER)-positive BC. The PLAM (GSE12027) and ER-positive BC (GSE42568, GSE29044, and GSE29431) datasets were obtained from the Gene Expression Omnibus database, and GEO2R was used to identify common differentially expressed genes (DEGs) between them. Functional annotation was performed, and a protein-protein interaction (PPI) network was constructed. Hub genes were identified and verified using western blotting and immunohistochemistry. We conducted an immune infiltration analysis; based on the results, selected 102 common DEGs for follow-up analysis. Functional analyses revealed that the DEGs were mostly enriched in cell proliferation, gene expression regulation, and tumor-related pathways. Four hub genes-ESR1, IL6, PLA2G4A, and CAV1-were further analyzed, and CAV1 was revealed to be associated with clinical outcomes and immune infiltration in ER-positive BC. This study proposes a common, possible pathogenesis of PLAM and ER-positive BC. These common pathways and pivotal genes may provide new directions for further mechanistic studies.

Targeting SPHK1/S1PR3-regulated S-1-P metabolic disorder triggers autophagic cell death in pulmonary lymphangiomyomatosis (LAM)

Lymphangioleiomyomatosis (LAM), a progressive pulmonary disease exclusively affecting females, is caused by defects or mutations in the coding gene tuberous sclerosis complex 1 (TSC1) or TSC2, causing the mammalian target of rapamycin complex 1 (mTORC1) activation and autophagy inhibition. Clinically, rapamycin shows limited cytocidal effects, and LAM recurs after drug withdrawal. In this study, we demonstrated that TSC2 negatively regulated the sphingolipid metabolism pathway and the expressions of sphingosine kinase 1 (SPHK1) and sphingosine-1-phosphate receptor 3 (S1PR3) were significantly elevated in LAM patient-derived TSC2-deficient cells compared to TSC2-addback cells, insensitive to rapamycin treatment and estrogen stimulation. Knockdown of SPHK1 showed reduced viability, migration and invasion in TSC2-deficient cells. Selective SPHK1 antagonist PF543 potently suppressed the viability of TSC2-deficient cells and induced autophagy-mediated cell death. Meanwhile, the cognate receptor S1PR3 was identified to mediating the tumorigenic effects of sphingosine-1-phosphate (S1P). Treatment with TY52156, a selective antagonist for S1PR3, or genetic silencing using S1PR3-siRNA suppressed the viability of TSC2-deficient cells. Both SPHK1 and S1PR3 inhibitors markedly exhibited antitumor effect in a xenograft model of TSC2-null cells, restored autophagy level, and triggered cell death. Together, we identified novel rapamycin-insensitive sphingosine metabolic signatures in TSC2-null LAM cells. Therapeutic targeting of aberrant SPHK1/S1P/S1PR3 signaling may have potent therapeutic benefit for patients with TSC/LAM or other hyperactive mTOR neoplasms with autophagy inhibition.

Analysis of Clinical Features and Next-Generation Sequencing of 12 Tuberous Sclerosis Families in China

Background

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disease with systemic organ involvement. So far, only a few TSC families in China have been reported. Therefore, more data on the clinical and genetic features of TSC families are required.

Materials and Methods

We retrospectively analyzed 12 TSC family probands and their family members. Next-generation sequencing (NGS) has been applied to confirm the type of TSC mutation along with a detailed physical examination.

Results

In this study, twenty-seven patients in 12 TSC families were reported, including 12 male and 15 female patients, aged 8-67 years. Skin lesions were detected among all patients with TSC, including 25 cases of facial angiofibromas, 18 cases of hypomelanotic macules, 15 cases of ungual fibromas, and 13 cases of shagreen patch. Other clinical features were also revealed: 14 cases of renal angiomyolipoma, 6 cases of subependymal nodules (SENs), and 3 cases of lymphangioleiomyomatosis. All twenty-seven patients with TSC were tested by NGS. Totally, TSC2 mutations were reported in 19 cases (7 frameshift mutations, 10 nonsense mutations, and 2 missense mutations), TSC1 mutations were reported in 4 cases (4 nonsense mutations), and 4 cases were genetically negative. The novel causal mutations (TSC2: c.208dup, c.1874C > G, c.1852del) identified in three families were first reported in TSC.

Conclusion

Our findings expand the mutation spectrum of patients with TSC in China. The clinical characteristics can vary among patients with TSC with the same pathogenic mutation. The genetic results and summary of clinical features of 12 TSC families contribute to a more accurate diagnosis and further genetic counseling.

A short review on cross-link between pyruvate kinase (PKM2) and Glioblastoma Multiforme

Pyruvate kinase (PK) catalyzes the last irreversible reaction of glycolysis pathway, generating pyruvate and ATP, from Phosphoenol Pyruvate (PEP) and ADP precursors. In mammals, four different tissue-specific isoforms (M1, M2, L and R) of PK exist, which are translated from two genes (PKL and PKR). PKM2 is the highly expressed isoform of PK in cancers, which regulates the aerobic glycolysis via reprogramming cancer cell's metabolic pathways to provide an anabolic advantage to the tumor cells. In addition to the established role of PKM2 in aerobic glycolysis of multiple cancer types, various recent findings have highlighted the non-metabolic functions of PKM2 in brain tumor development. Nuclear PKM2 acts as a co-activator and directly regulates gene transcription. PKM2 dependent transactivation of various oncogenic genes is instrumental in the progression and aggressiveness of Glioblastoma Multiforme (GBM). Also, PKM2 acts as a protein kinase in histone modification which regulates gene expression and tumorigenesis. Ongoing research has explored novel regulatory mechanisms of PKM2 and its association in GBM progression. This review enlists and summarizes the metabolic and non-metabolic roles of PKM2 at the cellular level, and its regulatory function highlights the importance of the nuclear functions of PKM2 in GBM progression, and an emerging role of PKM2 as novel cancer therapeutics.