Major Facilitator Superfamily Domain Research Articles

Abstract 4140121: Lipoprotein(a) Local Sybthesis And Plasma Uptake Via MDFS5 in Human Calcified Valve

Background: High circulating levels of lipoprotein(a) [Lp(a)] are associated with increased risk of calcific aortic stenosis (CAS). Targeting Lp(a) metabolism holds promise for therapeutic interventions. However, the precise mechanisms by which Lp(a) accumulates on aortic valves still not fully understood. Hypothesis: Lp(a) could be synthesized in situ in human aortic valves under specific stimuli, such as calcification, in addition to being taken up from plasma via membrane receptors, including the newly identified receptor Major Facilitator Superfamily Domain Containing 5 (MFSD5). Methods: Immunohistochemistry was used to detect the Lp(a) and its receptor MFSD5 in human aortic valves from CAS patients or controls, which were non-CAS patients. Plasma Lp(a) levels were measured in individuals undergoing aortic valve resection. Human valvular interstitial cells (VICs) were cultured in procalcifying medium, with or without Lp(a) (10uM) for 14 and 21 days. Von-kossa or Alizarin Red staining were used to assess valve calcification. Expression of Lp(a) and MFSD5 was analyzed with quantitative RT-PCR and western blot. Results: Lp(a) was nearly absent in control valve site, whereas it was abundantly present in valve site from CAS patients (p＜0.05). The higher the level of Lp(a) detected, the greater the extent of calcification noted in valve site. The mRNA and protein levels of Lp(a) extracted from calcified human valves were significantly higher compared to controls. However, the concentration of plasma Lp(a) did not affect the expression of Lp(a) in valve site (p＞0.05). In vitro studies showed that Lp(a) mRNA was minimally detectable in normal VICs, but was significantly upregulated following exposure to procalcifying medium (p < 0.05). Lp(a) incubation led to severer calcification than that induced by procalcifying medium alone (p < 0.05). As MFSD5 was a newly identified receptor of Lp(a), we also test its expression. MDFS5 was increased in human calcified valve (p＜0.05) and calcified VICs (p＜0.05). These results showed that the Lp(a) in valve could be increased by either uptake from serum or by synthesized locally by proper stimuli. Conclusion: Our study has shown that the degree of aortic valve calcification is correlated with the level of Lp(a) in the valve site rather than in serum. We also verified MFSD5 was the receptor of Lp(a) on human valve. Targeting Lp(a) accumulation at the valve site may offer a more effective strategy for the prevention or treatment of CAS.

RNA-seq and whole-genome re-sequencing reveal Micropterus salmoides growth-linked gene and selection signatures under carbohydrate-rich diet and varying temperature

This study was performed on Micropterus salmoides to determine growth-linked gene and single nucleotide polymorphism (SNP) markers under carbohydrate diet and varying temperature through RNA-seq and whole-genome re-sequencing. The results showed that growth-related genes were primarily enriched in the fat digestion and absorption signaling pathway, playing a role in lipid transport and metabolism. Fatty acid binding protein 6, bile salt-activated lipase-like, lysophosphatidylcholine acyltransferase 2, phospholipase A2, minor isoenzyme-like, and phospholipase A2, group IB (pancreas) were identified as the crucial genes. The differentially expressed genes between high and low temperatures were enriched in the pentose phosphate pathway, with carbohydrate transport and metabolism were most affected by temperature. Major facilitator superfamily domain containing 10, phosphogluconate dehydrogenase, fructose-1,6-bisphosphatase 1a, and spinster homolog 3 transcript variant X1(spns3) were the shared genes affected by temperature. From all the common genes, 10 growth-associated SNP markers were identified. The TT genotype at rs7781 was associated with lower body weight, while AA genotype at rs31434173 and CC genotype at rs31435313 showed positive correlation with body weight. Analogously, the GG genotype at rs31436887 and AA genotype at rs31438769 also found to characterize better growth performance. At low temperature, individuals with the AA genotype at rs11506587 and rs31435313 exhibited the slowest growth. For the genotypes labeled with rs11510589, the GG individual grew faster than the AA individual, whereas the opposite phenomenon occurred in these genotypes when labeled with rs11511314. The genotypes at rs32970704 and rs32967921 showed no growth correlation. The AA genotype at rs31435313 in spns3 had the slowest growth under a carbohydrate-rich diet regardless of the temperature. Our study presents candidate genes and SNP markers associated with growth influenced by carbohydrate and temperature, providing basis for the development of M. salmoides strain that better accepts carbohydrate diets at varying temperature.

MFSD7C protects hemolysis-induced lung impairments by inhibiting ferroptosis

Hemolysis drives susceptibility to lung injury and predicts poor outcomes in diseases, such as malaria and sickle cell disease (SCD). However, the underlying pathological mechanism remains elusive. Here, we report that major facilitator superfamily domain containing 7 C (MFSD7C) protects the lung from hemolytic-induced damage by preventing ferroptosis. Mechanistically, MFSD7C deficiency in HuLEC-5A cells leads to mitochondrial dysfunction, lipid remodeling and dysregulation of ACSL4 and GPX4, thereby enhancing lipid peroxidation and promoting ferroptosis. Furthermore, systemic administration of MFSD7C mRNA-loaded nanoparticles effectively prevents lung injury in hemolytic mice, such as HbSS-Townes mice and PHZ-challenged 7 C−/− mice. These findings present the detailed link between hemolytic complications and ferroptosis, providing potential therapeutic targets for patients with hemolytic disorders.

Interaction of major facilitator superfamily domain containing 2A with the blood-brain barrier.

The functional and structural integrity of the blood-brain barrier is crucial in maintaining homeostasis in the brain microenvironment; however, the molecular mechanisms underlying the formation and function of the blood-brain barrier remain poorly understood. The major facilitator superfamily domain containing 2A has been identified as a key regulator of blood-brain barrier function. It plays a critical role in promoting and maintaining the formation and functional stability of the blood-brain barrier, in addition to the transport of lipids, such as docosahexaenoic acid, across the blood-brain barrier. Furthermore, an increasing number of studies have suggested that major facilitator superfamily domain containing 2A is involved in the molecular mechanisms of blood-brain barrier dysfunction in a variety of neurological diseases; however, little is known regarding the mechanisms by which major facilitator superfamily domain containing 2A affects the blood-brain barrier. This paper provides a comprehensive and systematic review of the close relationship between major facilitator superfamily domain containing 2A proteins and the blood-brain barrier, including their basic structures and functions, cross-linking between major facilitator superfamily domain containing 2A and the blood-brain barrier, and the in-depth studies on lipid transport and the regulation of blood-brain barrier permeability. This comprehensive systematic review contributes to an in-depth understanding of the important role of major facilitator superfamily domain containing 2A proteins in maintaining the structure and function of the blood-brain barrier and the research progress to date. This will not only help to elucidate the pathogenesis of neurological diseases, improve the accuracy of laboratory diagnosis, and optimize clinical treatment strategies, but it may also play an important role in prognostic monitoring. In addition, the effects of major facilitator superfamily domain containing 2A on blood-brain barrier leakage in various diseases and the research progress on cross-blood-brain barrier drug delivery are summarized. This review may contribute to the development of new approaches for the treatment of neurological diseases.

Dietary sn-2 palmitate influences cognitive behavior by increasing the transport of liver-produced lysophosphatidylcholine VLCPUFAs to the brain

Investigations indicated that sn-2 palmitate have positive effects on brain development, although its mechanism remains largely unexamined. This research delved into how a diet abundant in sn-2 palmitate influenced the cognitive behavior of mice and elucidated the associated mechanisms using metabolomics and lipidomics. The study demonstrated that dietary sn-2 palmitate led to improved working memory and cognition in mice, as well as an increase in brain BDNF concentration when compared to those fed blend vegetable oil (BVO). This was because sn-2 palmitate feeding promoted the synthesis of very long-chain fatty acids (VLCPUFAs) for the lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) in the liver. This led to more efficient delivery of VLCPUFAs to the brain, as indicated by elevated concentration of LPC/LPE-VLCPUFAs in the liver and heightened expression of the major facilitator superfamily domain containing 2a (MFSD2A). In essence, this paper offered a potential mechanism by which sn-2 palmitate enhanced mouse neurodevelopment.

Maculopathy and adult-onset ataxia in patients with biallelic MFSD8 variants.

Biallelic variants in the major facilitator superfamily domain containing 8 gene (MFSD8) are associated with distinct clinical presentations that range from typical late-infantile neuronal ceroid lipofuscinosis type 7 (CLN7 disease) to isolated adult-onset retinal dystrophy. Classic late-infantile CLN7 disease is a severe, rare neurological disorder with an age of onset typically between 2 and 6 years, presenting with seizures and/or cognitive regression. Its clinical course is progressive, leading to premature death, and often includes visual loss due to severe retinal dystrophy. In rare cases, pathogenic variants in MFSD8 can be associated with isolated non-syndromic macular dystrophy with variable age at onset, in which the disease process predominantly or exclusively affects the cones of the macula and where there are no neurological or neuropsychiatric manifestations. Here we present longitudinal studies on four adult-onset patients who were biallelic for four MFSD8 variants. Two unrelated patients who presented with adult-onset ataxia and had macular dystrophy on examination were homozygous for a novel variant in MFSD8 NM_152778.4: c.935T>C p.(Ile312Thr). Two other patients presented in adulthood with visual symptoms, and one of these developed mild to moderate cerebellar ataxia years after the onset of visual symptoms. Our observations expand the knowledge on biallelic pathogenic MFSD8 variants and confirm that these are associated with a spectrum of more heterogeneous clinical phenotypes. In MFSD8-related disease, adult-onset recessive ataxia can be the presenting manifestation or may occur in combination with retinal dystrophy.

Unraveling the impact of deleterious nsSNPs on the MFSD1 protein

MFSD1 (Major facilitator superfamily domain containing 1) protein is a lysosomal multiple transmembrane-spanning protein responsible for the active transport of various compounds. Due to its potential role in maintaining liver homeostasis, any mutation might lead to altered protein expression, thus affecting the functionality. In this study, we explored the impact of deleterious nsSNPs (Nonsynonymous single nucleotide polymorphisms) on the stability, conformation, and functionality of the MFSD1 protein. SNP data and MFSD1 protein sequences were retrieved from NCBI dbSNP and Uniprot respectively. In total, five highly conserved nsSNPs were predicted to be deleterious based on their negative impact on the stability of the protein. Furthermore, the simulation analysis on the 3D structures of both native and mutant proteins revealed a notable impact on the physiological conformation of the protein. The identified variants not only affect the native conformation but also impact the association of MFSD1 with GLMP (Glycosylated Lysosomal Membrane Protein). In conclusion, the analysis revealed that the mutant protein's structural stability was inferior to that of the native protein. This research provides crucial insights for identifying and assessing MFSD1 mutations as potential diagnostic markers for liver-related diseases.

Automated collective variable discovery for MFSD2A transporter from molecular dynamics simulations

Biomolecules often exhibit complex free energy landscapes in which long-lived metastable states are separated by large energy barriers. Overcoming these barriers to robustly sample transitions between the metastable states with classical molecular dynamics (MD) simulations presents a challenge. To circumvent this issue, collective variable (CV)-based enhanced sampling MD approaches are often employed. Traditional CV selection relies on intuition and prior knowledge of the system. This approach introduces bias, which can lead to incomplete mechanistic insights. Thus, automated CV detection is desired to gain a deeper understanding of the system/process. Analysis of MD data with various machine-learning algorithms, such as principal component analysis (PCA), support vector machine, and linear discriminant analysis (LDA) based approaches have been implemented for automated CV detection. However, their performance has not been systematically evaluated on structurally and mechanistically complex biological systems. Here, we applied these methods to MD simulations of the MFSD2A (Major Facilitator Superfamily Domain 2A) lysolipid transporter in multiple functionally relevant metastable states with the goal of identifying optimal CVs that would structurally discriminate these states. Specific emphasis was on the automated detection and interpretive power of LDA-based CVs. We found that LDA methods, which included a novel gradient descent-based multiclass harmonic variant, termed GDHLDA, we developed here, outperform PCA in class separation, exhibiting remarkable consistency in extracting CVs critical for distinguishing metastable states. Furthermore, the identified CVs included features previously associated with conformational transitions in MFSD2A. Specifically, conformational shifts in transmembrane helix 7 and in residue Y294 on this helix emerged as critical features discriminating the metastable states in MFSD2A. This highlights the effectiveness of LDA-based approaches in automatically extracting from MD trajectories CVs of functional relevance that can be used to drive biased MD simulations to efficiently sample conformational transitions in the molecular system.

Glial growth factor 2 treatment alleviates ischemia and reperfusion-damaged integrity of the blood-brain barrier through decreasing Mfsd2a/caveolin-1-mediated transcellular and Pdlim5/YAP/TAZ-mediated paracellular permeability.

The impairment of blood-brain barrier (BBB) integrity is the pathological basis of hemorrhage transformation and vasogenic edema following thrombolysis and endovascular therapy. There is no approved drug in the clinic to reduce BBB damage after acute ischemic stroke (AIS). Glial growth factor 2 (GGF2), a recombinant version of neuregulin-1β that can stimulates glial cell proliferation and differentiation, has been shown to alleviate free radical release from activated microglial cells. We previously found that activated microglia and proinflammatory factors could disrupt BBB after AIS. In this study we investigated the effects of GGF2 on AIS-induced BBB damage as well as the underlying mechanisms. Mouse middle cerebral artery occlusion model was established: mice received a 90-min ischemia and 22.5 h reperfusion (I/R), and were treated with GGF2 (2.5, 12.5, 50 ng/kg, i.v.) before the reperfusion. We showed that GGF2 treatment dose-dependently decreased I/R-induced BBB damage detected by Evans blue (EB) and immunoglobulin G (IgG) leakage, and tight junction protein occludin degradation. In addition, we found that GGF2 dose-dependently reversed AIS-induced upregulation of vesicular transcytosis increase, caveolin-1 (Cav-1) as well as downregulation of major facilitator superfamily domain containing 2a (Mfsd2a). Moreover, GGF2 decreased I/R-induced upregulation of PDZ and LIM domain protein 5 (Pdlim5), an adaptor protein that played an important role in BBB damage after AIS. In addition, GGF2 significantly alleviated I/R-induced reduction of YAP and TAZ, microglial cell activation and upregulation of inflammatory factors. Together, these results demonstrate that GGF2 treatment alleviates the I/R-compromised integrity of BBB by inhibiting Mfsd2a/Cav-1-mediated transcellular permeability and Pdlim5/YAP/TAZ-mediated paracellular permeability.

MFSD1 with its accessory subunit GLMP functions as a general dipeptide uniporter in lysosomes

The lysosomal degradation of macromolecules produces diverse small metabolites exported by specific transporters for reuse in biosynthetic pathways. Here we deorphanized the major facilitator superfamily domain containing 1 (MFSD1) protein, which forms a tight complex with the glycosylated lysosomal membrane protein (GLMP) in the lysosomal membrane. Untargeted metabolomics analysis of MFSD1-deficient mouse lysosomes revealed an increase in cationic dipeptides. Purified MFSD1 selectively bound diverse dipeptides, while electrophysiological, isotope tracer and fluorescence-based studies in Xenopus oocytes and proteoliposomes showed that MFSD1–GLMP acts as a uniporter for cationic, neutral and anionic dipeptides. Cryoelectron microscopy structure of the dipeptide-bound MFSD1–GLMP complex in outward-open conformation characterized the heterodimer interface and, in combination with molecular dynamics simulations, provided a structural basis for its selectivity towards diverse dipeptides. Together, our data identify MFSD1 as a general lysosomal dipeptide uniporter, providing an alternative route to recycle lysosomal proteolysis products when lysosomal amino acid exporters are overloaded.

Intragenic MFSD8 duplication and histopathological findings in a rabbit with neuronal ceroid lipofuscinosis.

Neuronal ceroid lipofuscinoses (NCL) are among the most prevalent neurodegenerative disorders of early life in humans. Disease-causing variants have been described for 13 different NCL genes. In this study, a refined pathological characterization of a female rabbit with progressive neurological signs reminiscent of NCL was performed. Cytoplasmic pigment present in neurons was weakly positive with Sudan black B and autofluorescent. Immunohistology revealed astrogliosis, microgliosis and axonal degeneration. During the subsequent genetic investigation, the genome of the affected rabbit was sequenced and examined for private variants in NCL candidate genes. The analysis revealed a homozygous ~10.7 kb genomic duplication on chromosome 15 comprising parts of the MFSD8 gene, NC_013683.1:g.103,727,963_103,738,667dup. The duplication harbors two internal protein coding exons and is predicted to introduce a premature stop codon into the transcript, truncating ~50% of the wild-type MFSD8 open reading frame encoding the major facilitator superfamily domain containing protein 8, XP_002717309.2:p.(Glu235Leufs*23). Biallelic loss-of-function variants in MFSD8 have been described to cause NCL7 in human patients, dogs and a single cat. The available clinical and pathological data, together with current knowledge about MFSD8 variants and their functional impact in other species, point to the MFSD8 duplication as a likely causative defect for the observed phenotype in the affected rabbit.

Major Facilitator Superfamily Domain Containing 12 Is Overexpressed in Lung Cancer and Exhibits an Oncogenic Role in Lung Adenocarcinoma Cells.

Major facilitator superfamily domain containing 12 (MFSD12) regulates lysosomal cysteine import and promotes the proliferation and survival of melanoma cells. However, the expression and function of MFSD12 in other cancers, particularly in lung cancer, remain unclear. The expression of MFSD12 across various types of cancers and corresponding control tissues was examined using TIMER. MFSD12 expression in lung adenocarcinoma (LUAD) and its correlation with distinct clinicopathological features of LUAD patients were analyzed with UALCAN. The correlation between MFSD12 expression and survival of LUAD patients was assessed using the R package, survival, and the relationship between MFSD12 expression and immune infiltration status in LUAD was investigated using CIBERSORT. In addition, MFSD12 expression was knocked down in PC9 LUAD cells and their proliferation, capacity for expansion, cell cycle, apoptosis, and migration/invasion were evaluated through CCK-8 assays, colony formation assays, 7-AAD staining, Annexin V/PI staining, and Transwell assays, respectively. The stemness of these PC9 cells was determined through Western blotting, flow cytometry, and tumor sphere formation assays. MFSD12 mRNA levels were significantly elevated in multiple types of cancers, including LUAD. MFSD12 expression was also positively correlated with cancer stage, nodal metastasis, and infiltration of various immune cells in LUAD, and high MFSD12 levels predicted poor survival among LUAD patients. Knockdown of MFSD12 in PC9 cells resulted in decreased proliferation, attenuated colony formation capacity, cell cycle arrest, elevated apoptosis, impaired migration/invasion, and reduced stemness in PC9 cells. MFSD12 is an oncogene in LUAD.

P073 Enhancing the MFSD2A protein for the treatment of colitis-associated cancer: novel insights for pathogenesis and treatment

Abstract Background The intrinsic connection between inflammation and tumor promotion is well characterized and is a key pathogenic event in patients with colorectal cancer (CRC). A small fraction of patients with CRC suffers from genetic predisposition. However chronic inflammation, such as ulcerative colitis (UC), increases the risk of intestinal carcinogenesis, thus strengthening the connection between these conditions. A few years ago, our laboratory described that the intestinal endothelium isolated from actively inflamed UC patients displayed defective production of inflammation-resolving DHA-derived metabolites, by comparison with healthy controls and tissues in remission. We also reported that the Major Facilitator Superfamily Domain containing 2A (MFSD2A) participated in the production of the inflammation-resolving DHA-derived metabolites by the intestinal endothelium of patients with UC in remission, ameliorating colonic inflammation. Therefore, we hypothesized that the endothelial MFSD2A also has a role in preventing and/or counteracting cancer-associated inflammation. Methods Human Intestinal Microvascular Endothelial Cells (HIMEC) isolated from CRC and healthy samples were transduced with either MFSD2A protein-encoding lentiviral vectors (MFSD2A) or GFP as control, or MFSD2A targeting shRNA or its scramble, and were analyzed by lipidomics. Furthermore, Caco-2 cells co-cultured with HIMEC-MFSD2A were analyzed by FACS, evaluating their proliferation. Moreover, an orthotopic model of CRC was made intrarectally injecting CD1 nude mice with a cell mixture of Caco-2 and HUVEC overexpressing MFSD2A or GFP as control. Mice were gavaged with DHA-ethyl-ester or PBS. FACS analysis was performed on tumor and colonic samples. Results Lipidomic analysis revealed that the loss of MFSD2A in CRC is detrimental because there is a reduced production of pro-resolving lipids confirming that, as for UC, MFSD2A is important for the maintenance of an adequate balance between pro-resolving and pro-inflammatory phenotype. Moreover, enhancing MFSD2A expression at endothelial level limits Caco-2 cell proliferation, supporting its beneficial role. In addition, DHA administration in mice ameliorated clinical symptoms of inflammation upon intestinal endothelial MFSD2A overexpression, supporting the beneficial role of MFSD2A in vivo. Conclusion Tumor-associated inflammation remains a crucial hallmark of CRC. Our study seeks to identify the role of MFSD2A in the resolution phase of inflammation, pointing out alternative therapies for CRC treatment. These data suggested that MFSD2A might contrast the tumor-associated inflammation and ensure the correct balance between pro-inflammatory and pro-resolving milieu.

Essential role of MFSD1-GLMP-GIMAP5 in lymphocyte survival and liver homeostasis

We detected ENU-induced alleles of Mfsd1 (encoding the major facilitator superfamily domain containing 1 protein) that caused lymphopenia, splenomegaly, progressive liver pathology, and extramedullary hematopoiesis (EMH). MFSD1 is a lysosomal membrane-bound solute carrier protein with no previously described function in immunity. By proteomic analysis, we identified association between MFSD1 and both GLMP (glycosylated lysosomal membrane protein) and GIMAP5 (GTPase of immunity-associated protein 5). Germline knockout alleles of Mfsd1, Glmp, and Gimap5 each caused lymphopenia, liver pathology, EMH, and lipid deposition in the bone marrow and liver. We found that the interactions of MFSD1 and GLMP with GIMAP5 are essential to maintain normal GIMAP5 expression, which in turn is critical to support lymphocyte development and liver homeostasis that suppresses EMH. These findings identify the protein complex MFSD1-GLMP-GIMAP5 operating in hematopoietic and extrahematopoietic tissues to regulate immunity and liver homeostasis.

Knockdown of Placental Major Facilitator Superfamily Domain Containing 2a in Pregnant Mice Reduces Fetal Brain Growth and Phospholipid Docosahexaenoic Acid Content.

Docosahexaenoic acid (DHA) is an n-3 long chain polyunsaturated fatty acid critical for fetal brain development that is transported to the fetus from the mother by the placenta. The lysophosphatidylcholine (LPC) transporter, Major Facilitator Superfamily Domain Containing 2a (MFSD2a), is localized in the basal plasma membrane of the syncytiotrophoblast of the human placenta, and MFSD2a expression correlates with umbilical cord blood LPC-DHA levels in human pregnancy. We hypothesized that placenta-specific knockdown of MFSD2a in pregnant mice reduces phospholipid DHA accumulation in the fetal brain. Mouse blastocysts (E3.5) were transduced with an EGFP-expressing lentivirus containing either an shRNA targeting MFSD2a or a non-coding sequence (SCR), then transferred to pseudopregnant females. At E18.5, fetuses were weighed and their placenta, brain, liver and plasma were collected. MFSD2a mRNA expression was determined by qPCR in the brain, liver and placenta and phospholipid DHA was quantified by LC-MS/MS. MFSD2a-targeting shRNA reduced placental mRNA MFSD2a expression by 38% at E18.5 (n = 45, p < 0.008) compared with SCR controls. MFSD2a expression in the fetal brain and liver were unchanged. Fetal brain weight was reduced by 13% (p = 0.006). Body weight, placenta and liver weights were unaffected. Fetal brain phosphatidyl choline and phosphatidyl ethanolamine DHA content was lower in fetuses with placenta-specific MFSD2a knockdown. Placenta-specific reduction in expression of the LPC-DHA transporter MFSD2a resulted in reduced fetal brain weight and lower phospholipid DHA content in the fetal brain. These data provide mechanistic evidence that placental MFSD2a mediates maternal-fetal transfer of LPC-DHA, which is critical for brain growth.

Major Facilitator Superfamily Domain Containing 5 Inhibition Reduces Lipoprotein(a) Uptake and Calcification in Valvular Heart Disease.

High circulating levels of Lp(a) (lipoprotein[a]) increase the risk of atherosclerosis and calcific aortic valve disease, affecting millions of patients worldwide. Although atherosclerosis is commonly treated with low-density lipoprotein-targeting therapies, these do not reduce Lp(a) or risk of calcific aortic valve disease, which has no available drug therapies. Targeting Lp(a) production and catabolism may provide therapeutic benefit, but little is known about Lp(a) cellular uptake. Here, unbiased ligand-receptor capture mass spectrometry was used to identify MFSD5 (major facilitator superfamily domain containing 5) as a novel receptor/cofactor involved in Lp(a) uptake. Reducing MFSD5 expression by a computationally identified small molecule or small interfering RNA suppressed Lp(a) uptake and calcification in primary human valvular endothelial and interstitial cells. MFSD5 variants were associated with aortic stenosis (P=0.027 after multiple hypothesis testing) with evidence suggestive of an interaction with plasma Lp(a) levels. MFSD5 knockdown suppressing human valvular cell Lp(a) uptake and calcification, along with meta-analysis of MFSD5 variants associating with aortic stenosis, supports further preclinical assessment of MFSD5 in cardiovascular diseases, the leading cause of death worldwide.

Extraction ofcharacteristic serum microRNAs andprediction oftarget genes in IgG4-related dacryoadenitis and sialadenitis.

To identify the specific microRNAs (miRNAs) in IgG4-related dacryoadenitis and sialadenitis (IgG4-DS) and predict the targeted genes. miRNAs in the serum of nine patients with IgG4-DS, three patients with primary Sjögren's syndrome, and three healthy controls were analysed using the human miRNA chip, and miRNAs that exhibited significant fluctuation in expression in IgG4-DS patients were extracted. The respective target genes were predicted using an existing database, and expression of the target genes was evaluated in actual submandibular gland tissues affected by IgG4-DS. Serum miR-125a-3p and miR-125b-1-3p levels were elevated in IgG4-DS. Six candidate target genes (glypican 4, forkhead box C1, protein tyrosine phosphatase non-receptor type 3, hydroxycarboxylic acid receptor 1, major facilitator superfamily domain containing 11, and tumour-associated calcium signal transducer 2) were downregulated in the affected submandibular gland tissue. Overexpression of miR-125a-3p and miR-125b-1-3p is a hallmark of IgG4-DS. These miRNAs appear to be involved in the pathogenesis of IgG4-DS.

Lysosomal cyst(e)ine storage potentiates tolerance to oxidative stress in cancer cells

Cyst(e)ine is a key precursor for the synthesis of glutathione (GSH), which protects cancer cells from oxidative stress. Cyst(e)ine is stored in lysosomes, but its role in redox regulation is unclear. Here, we show that breast cancer cells upregulate major facilitator superfamily domain containing 12 (MFSD12) to increase lysosomal cyst(e)ine storage, which is released by cystinosin (CTNS) to maintain GSH levels and buffer oxidative stress. We find that mTORC1 regulates MFSD12 by directly phosphorylating residue T254, while mTORC1 inhibition enhances lysosome acidification that activates CTNS. This switch modulates lysosomal cyst(e)ine levels in response to oxidative stress, fine-tuning redox homeostasis to enhance cell fitness. MFSD12-T254A mutant inhibits MFSD12 function and suppresses tumor progression. Moreover, MFSD12 overexpression correlates with poor neoadjuvant chemotherapy response and prognosis in breast cancer patients. Our findings reveal the critical role of lysosomal cyst(e)ine storage in adaptive redox homeostasis and suggest that MFSD12 is a potential therapeutic target.

MFSD2A potentiates gastric cancer response to anti-PD-1 immunotherapy by reprogramming the tumor microenvironment to activate T cell response.

The efficacy of anti-programmed cell death protein 1 (PD-1) immunotherapy in various cancers, including gastric cancer (GC), needs to be potentiated by more effective targeting to enhance therapeutic efficacy or identifying accurate biomarkers to predict clinical responses. Here, we attempted to identify molecules predicting or/and promoting anti-PD-1 therapeutic response in advanced GC (AGC). The transcriptome of AGC tissues from patients with different clinical responses to anti-PD-1 immunotherapy and GC cells was analyzed by RNA sequencing. The protein and mRNA levels of the major facilitator superfamily domain containing 2A (MFSD2A) in GC cells were assessed via quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry. Additionally, the regulation of anti-PD-1 response by MFSD2A was studied in tumor-bearing mice. Cytometry by Time-of-Flight, multiple immunohistochemistry, and flow cytometry assays were used to explore immunological responses. The effects of MFSD2A on lipid metabolism in mice cancer tissue and GC cells was detected by metabolomics. Higher expression of MFSD2A in tumor tissues of AGC patients was associated with better response to anti-PD-1 immunotherapy. Moreover, MFSD2A expression was lower in GC tissues compared to adjacent normal tissues, and its expression was inversely correlated with GC stage. The overexpression of MFSD2A in GC cells enhanced the efficacy of anti-PD-1 immunotherapy in vivo by reprogramming the tumor microenvironment (TME), characterized by increased CD8+ T cell activation and reduced its exhaustion. MFSD2A inhibited transforming growth factor β1 (TGFβ1) release from GC cells by suppressing cyclooxygenase 2 (COX2)-prostaglandin synthesis, which consequently reprogrammed TME to promote anti-tumor T cell activation. MFSD2A potentially serves as a predictive biomarker for anti-PD-1 immunotherapy response in AGC patients. MFSD2A may be a promising therapeutic target to potentiate the efficacy of anti-PD-1 immunotherapy by reprogramming the TME to promote T cells activation.

JMJD6 functions as an oncogene and is associated with poor prognosis in esophageal squamous cell carcinoma

BackgroundEsophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors with a high prevalence and poor prognosis. It is an urgent problem to deeply understand the molecular mechanism of ESCC and develop effective diagnostic and prognostic methods.MethodsUsing tumor tissue and corresponding paracancerous samples from 141 resected ESCC patients, we assessed Jumonji domain-containing protein 6 (JMJD6) expression using Immunohistochemical (IHC) staining. Kaplan-Meier survival analysis and univariate or multivariate analysis were used to investigate the relationship between JMJD6 expression and clinicopathological features. The expression status and prognostic value of JMJD6 were analyzed by bioinformatics and enrichment analysis.ResultsThe expression of JMJD6 in ESCC samples was higher than that in the corresponding paracancerous samples, and high expression of JMJD6 was positively associated with poor prognosis of ESCC patients. In addition, bioinformatics analysis of the expression and prognosis of JMJD6 in a variety of tumors showed that high expression of JMJD6 was significantly associated with poor overall survival (OS) in ESCC patients. Enrichment analysis indicated that the high expression of genes similar to JMJD6, such as Conserved oligomeric Golgi 1(COG1), Major facilitator superfamily domain 11 (MFSD11) and Death Effector Domain Containing 2 (DEDD2), was associated with poor prognosis of ESCC, suggesting that JMJD6 might be involved in the occurrence and prognosis of ESCC.ConclusionOur study found that JMJD6 expression was significantly increased in ESCC patients and positively correlated with prognosis, indicating that targeting JMJD6 might be an attractive prognostic biomarker and provides a potential treatment strategy for ESCC.Trial registrationThe study was approved by Tangdu Hospital ethics committee (No. TDLL-202110-02).