Metabolism Of Fibroblasts Research Articles

Studying the impact of selenium complex chemical structure on collagen-starch hydrogels for enhanced tissue growth

ABSTRACT Selenium complexes modifying their chemical structure through the variation of amino acids such as L-phenylalanine, L-histidine, and L-tryptophan were dispersed in collagen-starch hydrogels (1 wt.%), generating the (Se-F), (Se-H), and (Se-T) biomatrices, respectively. SEM/EDS analysis confirmed a uniform selenium distribution, with (Se-H) biomatrix displaying the largest aggregates, influencing the formation and size of aggregates within the biopolymer matrix. All matrices exhibited a semicrystalline nature; notably (Se-T) decreased fibrillar structure crystallinity of collagen. Physicochemical assessments revealed (Se-H) with the shortest gelation time (10 ± 1 minutes), highest swelling (4500 ± 230%) and superior resistance to proteolytic degradation. (Se-T) demonstrated the highest crosslinking index (52 ± 4%), while (Se-F) was characterized by having the highest storage modulus (840 Pa at 1 hz), enabling the sustained release of methylene blue for up to 7 days. Upon contact with commercial plant substrate, all matrices showed negligible mass variation. Biological findings showcased (Se-F) stimulating monocyte metabolism and proliferation, while (Se-H) fostered fibroblast metabolism, proliferation, and interleukin-10 (IL-10) secretion in monocytes, alongside reduced tumor necrosis factor-alpha (TNF-α) secretion. All matrices decreased TNF-α secretion in monocytes, signifying potential as advanced wound healing dressings. For plant tissue, all matrices enhanced tomato cell metabolism and proliferation. Seeds grown on commercial plant substrate revealed (Se-F) yielding plants with larger stem sizes, while (Se-T) resulted in higher leaf counts within 30 days, indicating their potential agricultural applications.

Human Skin Fibroblasts as an In Vitro Model Illustrating Changes in Collagen Levels and Skin Cell Migration Under the Influence of Selected Plant Hormones

Human skin fibroblasts are an excellent in vitro model for tracking the processes occurring in human skin and studying the potential impact of various biologically active substances on these processes. Two plant hormones, which are included in the cytokinins group—kinetin (K) and N-6-benzyladenine (BA)—have a positive effect on human skin. Therefore, an attempt was made to examine the effect they have on key skin functions, cell proliferation, and migration, as well as collagen synthesis in them. The effect of phytohormones was studied at selected concentrations for kinetin—10 μM and 1 μM—and for N-6-benzyladenine—1 μM and 0.1 μM. A wound-healing assay was used in order to analyze cell migration and proliferation. The content of total protein and collagen in cells and culture medium was determined. The obtained results confirm that the studied compounds induce cell migration and proliferation, as well as collagen biosynthesis. The positive effect of kinetin and N-6-benzyladenine on fibroblast metabolism that we have demonstrated allows us to indicate them as compounds with potentially therapeutic properties. Therefore, we conclude that they should be subjected to further molecular and in vivo studies focusing on pathologies connected with skin diseases and aging.

Abstract A018: Alternative Polyadenylation Regulates Pancreatic Cancer Fibroblast Metabolism

Abstract Dense, fibrotic stroma is a defining feature of pancreatic ductal adenocarcinoma (PDAC), comprising up to 90% of tumor volume. Multiple studies have shown that this stroma strongly influences cancer progression and response to treatment. Cancer Associated Fibroblasts (CAFs) make up the majority of the Tumor Microenvironment (TME) and directly alter the tumor landscape and response to therapeutics. CAFs are a heterogenous population comprising of a mixture of inflammatory, myofibroblastic, and antigen-presenting CAFs, with both pro- and anti- tumorigenic functions. While we have been able to define CAFs phenotypically, we lack a deeper understanding of the mechanisms underlying their transcriptional heterogeneity and ultimately their contribution to driving PDAC progression. Our lab has previously shown 3’UTR-Alternative Polyadenylation (APA) to be an important driver of genetic dysregulation in PDAC. APA is an important process regulating mRNA stability, protein localization, and expression, ultimately determining cellular processes such as proliferation, metastasis, and migration. We have also shown that increased 3’ UTR shortening is associated with the pro- tumorigenic inflammatory CAF subtype. However, how APA regulates CAF function is unknown. We are now trying to understand the possible mechanisms of these changes in vitro using human-derived CAF cell lines and treating them with a known pharmacological modulator of APA. We performed PAC-Seq analyses on these samples and show that important drivers of CAF metabolism are hindered by APA, ultimately affecting the ability of CAFs to support cancer cell growth. We find that inhibition of APA drives CAF migration and senescence phenotype and alters gene expression of critical genes required for CAF function, and metabolism. We identified a novel mechanism by which a key metabolic gene SLC7A11 is regulated by APA. To our knowledge, our work is one of the first studies to study how APA is an important regulator of CAF function. Citation Format: Aditi H Chaubey, Michael E Feigin, Eric J Wagner. Alternative Polyadenylation Regulates Pancreatic Cancer Fibroblast Metabolism [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr A018.

Modulation of animal and plant tissue growth with collagen‐starch‐organic molybdenum networks hydrogel biomatrices

AbstractThe development of hydrogel biomatrices with potential to modulate animal and plant tissue growth is ongoing. In this study, molybdenum bio‐metal–organic frameworks (MOFs) (Mo‐bioMOFs) incorporating essential amino acids such as l‐histidine (Mo‐His), l‐phenylalanine (Mo‐Phe), and l‐tryptophan (Mo‐Trp) were encapsulated in semi‐interpenetrating polymer network (semi‐IPN) hydrogels composed of collagen and starch. The structure and properties of these materials show dependence on the amino acid that constitutes the Mo‐bioMOFs. The biomatrices have a semi‐crystalline surface with increased porosity when using Mo‐His; this system also benefits swelling. Increased crosslinking, acceleration in gelation, and mechanical improvement are observed for the system based on Mo‐Phe. Methylene blue release experiments were conducted, demonstrating that matrices including Mo‐bioMOFs exhibit controlled release profiles, indicating highly stable retention of Mo‐bioMOFs in the semi‐IPN matrix. The biomatrices enhance the metabolism and proliferation of fibroblasts and monocytes, with Mo‐Trp reducing the secretion of inflammatory cytokines like TNF‐α. The biomatrices exhibit gradual and slow mass loss when exposed to collagenase and commercial vegetable substrates. Both leaf and root cells of tomato plants (Solanum lycopersicum) show increased metabolism and growth when exposed to Mo‐Phe and Mo‐His. Notably, the biomatrix containing Mo‐Phe promotes the most substantial plant growth and foliage after 30 days. These biomatrices have potential applications in chronic wound healing and agriculture.

Sanqi oral solution ameliorates renal fibrosis by suppressing fibroblast activation via HIF-1α/PKM2/glycolysis pathway in chronic kidney disease

Ethnopharmacological relevanceSanqi oral solution (SQ) is a traditional Chinese patent medicine, widely used to treat chronic kidney diseases (CKD) in the clinic in China. Previous studies have confirmed its anti-renal fibrosis effect, but the specific pharmacological mechanism is still unclear. Aim of the studyFocusing on energy metabolism in fibroblasts, the renoprotective mechanism of SQ was investigated in vitro and in vivo. MethodsFirstly, the fingerprint of SQ was constructed and its elementary chemical composition was analyzed. In the 5/6Nx rats experiment, the efficacy of SQ on the kidney was evaluated by detecting serum and urine biochemical indexes and pathological staining of renal tissues. Lactic acid and pyruvic acid levels in serum and renal tissues were detected. PCNA protein expression in kidney tissue was detected by immunofluorescence assay and Western blot. Expression levels of HIF-1α, PKM2 and HK2 were determined by immunohistochemistry, Western blot or RT-qPCR assay. In addition, the effect of SQ intervention on cell proliferation and glycolysis was evaluated in TGF-β1-induced NRK-49F cells, and the role of SQ exposure and HIF-1α/PKM2/glycolysis pathway were further investigated by silencing and overexpressing HIF-1α gene in NRK-49F cells. ResultsIn 5/6 Nx rats, SQ effectively improved renal function and treated renal injury. It reduced the levels of lactic acid and pyruvic acid in kidney homogenates from CKD rats and decreased the expression levels of HIF-1α, PKM2, HK2, α-SMA, vimentin, collagen I and PCNA in kidney tissues. Similar results were observed in vitro. SQ inhibited NRK-49F cell proliferation, glycolysis and the expression levels of HIF-1α, PKM2 induced by TGF-β1. Furthermore, we established NRK-49F cells transfected with siRNA or pDNA to silence or overexpress the HIF-1α gene. Overexpression of HIF-1α promoted cellular secretion of lactic acid and pyruvic acid in TGF-β1-induced NRK-49F cells, however, this change was reversed by intervention with SQ or silencing the HIF-1α gene. Overexpression of HIF-1α can further induce increased PKM2 expression, while SQ intervention can reduce PKM2 expression. Moreover, PKM2 expression was also inhibited after silencing HIF-1α gene, and SQ was not effective even when given. ConclusionThe mechanism of action of SQ was explored from the perspective of energy metabolism, and it was found to regulate PKM2-activated glycolysis, inhibit fibroblast activation, and further ameliorate renal fibrosis in CKD by targeting HIF-1α.

Silencing of cysteine and serine rich nuclear protein 1 inhibits apoptosis, senescence and collagen degradation in human-derived vaginal fibroblasts in response to oxidative stress or DNA damage

Pelvic organ prolapse (POP) is a group of diseases caused by extracellular matrix (ECM) degradation in pelvic supportive tissues. Cysteine and serine rich nuclear protein 1 (CSRNP1) is involved in cell proliferation and survival regulation, and reportedly facilitates collagen breakdown in human chondrocytes. The present study aimed to probe the effect of CSRNP1 on collagen metabolism in human-derived vaginal fibroblasts. High expression of CSRNP1 was found in POP patient-derived vaginal fibroblasts in comparison to normal-derived vaginal fibroblasts. Following functional experiments revealed that CSRNP1 overexpression led to proliferation inhibition, apoptosis and collagen degradation in normal vaginal fibroblasts. In line with this, silencing of CSRNP1 inhibited hydrogen peroxide (H2O2)-triggered apoptosis, ROS generation and collagen loss in normal vaginal fibroblasts. Silencing of CSRNP1 also reduced the expression of cell senescence markers p21 and γ-H2Ax (the histone H2Ax phosphorylated at Ser139), as well as curbed collagen breakdown in normal vaginal fibroblasts caused by a DNA damage agent etoposide. Transcriptomic analysis of vaginal fibroblasts showed that differentially expressed genes affected by CSRNP1 overexpression were mainly enriched in the Wnt signaling pathway. Treatment with a Wnt pathway inhibitor DKK1 blocked CSRNP1 knockdown-caused collagen deposition. Mechanistically, CSRNP1 was identified to be a target of Snail family transcriptional repressor 2 (SNAI2). Forced expression of CSRNP1 reversed the anti-apoptotic, anti-senescent and anti-collagen loss effects of SNAI2 in normal vaginal fibroblasts exposed to H2O2 or etoposide. Our study indicates that the SNAI2/CSRNP1 axis may be a key driver in POP progression, which provides a potential therapeutic strategy for POP.

Abstract 3155: Metabolic stress induces an intrinsic inflammatory CAF phenotype that regulates stromal architecture in pancreatic cancer

Abstract Macropinocytosis is a critical amino acid supply pathway that fuels the metabolism of tumor cells and cancer-associated fibroblasts (CAFs) in pancreatic ductal adenocarcinoma (PDAC). PDAC tumors are deficient in glutamine, a critical amino acid that tumor cells and CAFs use to sustain their cellular fitness. We have previously shown that both PDAC cells and CAFs stimulate macropinocytosis as an adaptive response to glutamine depletion. How these linked metabolic mechanisms might co-operate to control stromal architecture remains elusive. In this study, we employed glutamine starvation and 5-(N-ethyl-N-isopropyl)-amiloride (EIPA), a selective inhibitor of macropinocytosis, to investigate how metabolic stress impacts the tumor microenvironment. We find that concomitant suppression of glutamine metabolism and macropinocytosis synergizes to drive an intrinsic inflammatory CAF phenotype that requires metabolic stress-induced ERK/MAPK signaling. Utilizing immunocompetent syngeneic mouse models of PDAC, we find that blocking macropinocytosis in these glutamine-depleted tumors diminishes tumor growth and reorganizes the tumor stroma by decreasing collagen deposition, increasing vasculature expansion and enhancing the infiltration of both CD8+ and CD4+ T cells. Alterations in the stromal landscape under these conditions are linked to the enhancement of CAFs that display an inflammatory signature while simultaneously suppressing more myofibroblastic identities within the tumor. Interestingly, we find that these effects on the tumor microenvironment can be harnessed to improve therapeutic responses. We determine that combining macropinocytosis inhibition with immune checkpoint blockade reduces PDAC tumor burden and significantly inhibits metastasis. We also find that macropinocytosis inhibition enhances drug delivery, thereby improving the efficacy of gemcitabine chemotherapy. Our findings demonstrate that intratumoral metabolic stress plays a critical part in preserving and modulating the tumor stroma. Citation Format: Yijuan Zhang, Swetha Maganti, Jennifer Hope, Li Lin, Cheska Marie Galapate, Florent Carrette, Linda Bradley, Cosimo Commisso. Metabolic stress induces an intrinsic inflammatory CAF phenotype that regulates stromal architecture in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3155.

Enhanced lipid biosynthesis in oral squamous cell carcinoma cancer-associated fibroblasts contributes to tumor progression: Role of IL8/AKT/p-ACLY axis.

Lipid metabolic reprogramming of tumor cells has been proven to play a critical role in tumor initiation and development. However, lipid metabolism in cancer-associated fibroblasts (CAFs) has rarely been studied, particularly in CAFs of oral squamous cell carcinoma (OSCC). Additionally, the molecular mechanism by which tumor cells regulate lipid metabolism in fibroblasts is unclear. In this study, we found that phosphorylated ATP citrate lyase (p-ACLY), a key lipid metabolic enzyme, was upregulated in OSCC CAFs. Compared to paracancerous normal fibroblasts, CAFs showed enhanced lipid synthesis, such as elevated cytosolic acetyl-CoA level and accumulation of lipid droplets. Conversely, reduction of p-ACLY level blocked this biological process. In addition, blocking lipid synthesis in CAFs or inhibiting fatty acid uptake by OSCC cells reduced the promotive effects of CAFs on OSCC cell proliferation, invasion, and migration. These findings suggested that CAFs are one of lipid sources required for OSCC progression. Mechanistically, AKT signaling activation was involved in the upregulation of p-ACLY level and lipid synthesis in CAFs. Interleukin-8 (IL8), an exocrine cytokine of OSCC cells, could activate AKT and then phosphorylate ACLY in fibroblasts. This study suggested that the IL8/AKT/p-ACLY axis could be considered as a potential target for OSCC treatment.

Dendritic nanomedicine enhances chemo-immunotherapy by disturbing metabolism of cancer-associated fibroblasts for deep penetration and activating function of immune cells

Inefficient drug penetration hurdled by the stroma in the tumor tissue leads to a diminished therapeutic effect for drugs and a reduced infiltration level of immune cells. Herein, we constructed a PEGylated dendritic epirubicin (Epi) prodrug (Epi-P4D) to regulate the metabolism of cancer-associated fibroblasts (CAFs), thus enhancing Epi penetration into both multicellular tumor spheroids (MTSs) and tumor tissues in mouse colon cancer (CT26), mouse breast cancer (4T1) and human breast cancer (MDA-MB-231) models. Enhanced cytotoxicity against CT26 MTSs and remarkable antitumor efficacy of Epi-P4D were ascribed to reduced fibronectin, α-SMA, and collagen secretion. Besides, thinning of the tumor tissue stroma and efficient eradication of tumor cells promoted the immunogenic cell death effect for dendritic cell (DC) maturation and subsequent immune activation, including elevating the CD4+ T cell population, reducing CD4+ and CD8+ T cell hyperactivation and exhaustion, and amplifying the natural killer (NK) cell proportion and effectively activating them. As a result, this dendritic nanomedicine thinned the stroma of tumor tissues to enhance drug penetration and facilitate immune cell infiltration for elevated antitumor efficacy.

Comparison of the Regenerative Metabolic Efficiency of Lipid Extracts from Microalgae Nannochloropsis oceanica and Chlorococcum amblystomatis on Fibroblasts.

UVA radiation leads to oxidative stress and inflammation in skin cells. Therefore, the aim of this study was to compare the effect of lipid extracts from microalgae Nannochloropsis oceanica (N.o.) (marine) and Chlorococcum amblystomatis (C.a.) (freshwater) on the redox balance and PUFA metabolism in human skin fibroblasts modified by UVA. Lipid extracts from both types of microalgae introduced into the fibroblast medium after UVA irradiation significantly reduced the level of ROS and enhanced expression of Nrf2, which increased the activity/level of antioxidants (SOD1/2, CAT, GSH, Trx). The reduction in oxidative stress was accompanied by a decrease in the level of 4-HNE, its protein adducts and protein carbonyl groups. Microalgae also reduced the activity of COX1/2, FAAH and MAGL increased by UVA, and as a consequence, the level of lipid mediators (especially after N.o.) decreased, both from the group of endocannabinoids (AEA, 2-AG, PEA) and eicosanoids (PGE2, 15d-PGJ2, TXB2, 15-HETE), acting mainly through receptors related to G protein, the expression of which increases after UVA. This further contributed to the reduction in oxidative stress and pro-inflammatory signaling at NF-κB and TNFα levels. Therefore, it is suggested that lipid extracts from both N.o. and C.a. microalgae can be used to regenerate fibroblast metabolism disturbed by UVA radiation.

Azithromycin-loaded liposomes and niosomes for the treatment of skin infections: Influence of excipients and preparative methods on the functional properties

The aim of this study was to develop azithromycin (AZT)-loaded liposomes (LP) and niosomes (NS) useful for the treatment of bacterial skin infections and acne. LP based on phosphatidylcholine from egg yolk (EPC) or from soybean lecithin (SPC), and NS composed of sorbitan monopalmitate (Span 40) or sorbitan monostearate (Span 60) were prepared through the thin film hydration (TFH) and the ethanol injection (EI) methods. The formulations were subsequently characterized for their physico-chemical and functional properties. Vesicles prepared through TFH showed higher average sizes than the corresponding formulations obtained by EI. All the vesicles presented adequate encapsulation efficiency and a negative ζ potential, which assured good stability during the storage period (except for LP-SPC). Formulations prepared with TFH showed a more prolonged AZT release than those prepared through EI, due to their lower surface area and multilamellar structure, as confirmed by atomic force microscopy nanomechanical characterization. Finally, among all the formulations, NS-Span 40-TFH and LP-EPC-TFH allowed the highest drug accumulation in the skin, retained the antimicrobial activity and did not alter fibroblast metabolism and viability. Overall, they could ensure to minimize the dosing and the administration frequency, thus representing promising candidates for the treatment of bacterial skin infections and acne.

Crosstalk between oxygen signaling and iron metabolism in renal interstitial fibroblasts.

To maintain the oxygen supply, the production of red blood cells (erythrocytes) is promoted under low-oxygen conditions (hypoxia). Oxygen is carried by hemoglobin in erythrocytes, in which the majority of the essential element iron in the body is contained. Because iron metabolism is strictly controlled in a semi-closed recycling system to protect cells from oxidative stress caused by iron, hypoxia-inducible erythropoiesis is closely coordinated by regulatory systems that mobilize stored iron for hemoglobin synthesis. The erythroid growth factor erythropoietin (EPO) is mainly secreted by interstitial fibroblasts in the renal cortex, which are known as renal EPO-producing (REP) cells, and promotes erythropoiesis and iron mobilization. Intriguingly, EPO production is strongly induced by hypoxia through iron-dependent pathways in REP cells. Here, we summarize recent studies on the network mechanisms linking hypoxia-inducible EPO production, erythropoiesis and iron metabolism. Additionally, we introduce disease mechanisms related to disorders in the network mediated by REP cell functions. Furthermore, we propose future studies regarding the application of renal cells derived from the urine of kidney disease patients to investigate the molecular pathology of chronic kidney disease and develop precise and personalized medicine for kidney disease.

Initial phase of anthracycline cardiotoxicity involves metabolic switch and activation of cardiac fibroblasts

Abstract Background Doxorubicin (DOX) is an effective anticancer drug, but its application is hampered by cardiotoxicity with asymptomatic diastolic dysfunction as the earliest manifestation. Interstitial fibrosis leads to impaired relaxation, but the timing of fibrotic process and the mechanisms that operate shortly after DOX exposure are not clear. While changes in energy metabolism by DOX is recognized in cardiomyocytes, the effects of DOX on cardiac fibroblasts (CFs) metabolism are unknown.Thus, in a model of anthracycline cardiomyopathy, we asked whether the activation of CFs anticipates the onset of DOX-induced early diastolic dysfunction and evaluated the effects of DOX on the activation and metabolism of CFs. Methods Fischer 344 rats were exposed to 6 injections of 2.5 mg/kg of DOX over 2 weeks. Heart function was assessed by echocardiography and left ventricular catheterization. To test the very early in vivo effects of DOX on CFs, primary CFs were isolated from hearts of DOX-treated rats after the first injection of DOX. In another set of experiments, CFs were exposed to DOX in vitro. Cell metabolism was measured by a Seahorse-XF Real-Time ATP assay and cell phenotype was determined by immunocytochemistry and molecular biology. Results Early effects of DOX consisted of unchanged ejection fraction and the evidence of diastolic dysfunction. Markers of pro-fibrotic remodeling and histological evidence of CFs transformation were present in the heart immediately after treatment completion. Importantly, at the very beginning of the DOXO exposure, when cardiac function was normal and there was no histological evidence of increased fibrosis, the conversion of CFs to myofibroblasts, evidenced by SMA, was detected. Oxygen consumption rate and extracellular acidification, revealed the increased metabolic activity of CFs after DOX exposure and the switch to the glycolytic energy production. These effects were consistent in CFs isolated from the hearts of DOX-treated animals and in naive CFs exposed to DOX in vitro. The metabolic switch was paralleled with the phenotype change of CFs towards extracellular matrix-producing cells. Upon DOX, CFs upregulated markers of myofibroblast differentiation and the activation of pro-fibrotic signaling (aSMA, TGFb and phospho-SMAD). CFs maintained their functional properties in scratch assay. CFs upregulated also NOX2, indicating these cells as an intramyocardial source of reactive oxygen in the initial phase of the disease. Conclusion The metabolic switch and activation of CFs anticipate the onset of DOX-induced early diastolic dysfunction. The effect of DOX on the metabolic profile in CFs represents a novel and potentially targetable component of the very early phase of the pathogenesis of anthracycline cardiomyopathy.

Dual inhibitor targets fibroblast metabolism in RA.

Dual inhibitor targets fibroblast metabolism in RA.

Mechanical stiffness promotes skin fibrosis through Piezo1-mediated arginine and proline metabolism

The increased mechanics of fibrotic skin tissue continuously regulate fibroblast functions such as survival and differentiation. Although all these processes consume metabolites, it is unclear whether and how cells adapt their metabolic activity to increased matrix stiffness. Here, we show that transferring mouse dermal fibroblasts from soft to stiff substrates causes an up-regulation of arginine and proline metabolism. Increased matrix stiffness stimulates the expression and activity of key metabolic enzymes, leading to the synthesis of L-proline, a major source of collagen. In addition, the novel mechanosensitive channel Piezo1 was identified as a key regulator of arginine and proline metabolism in fibroblasts under increased stiffness. Consistently, targeting Piezo1 to dermal fibroblasts in vivo effectively reduces fibrosis and arginine-proline metabolism in mouse skin. Therefore, mechanical stiffness is a critical environmental cue for fibroblast metabolism and skin fibrosis progression.

Voltage-dependent anion channel 1 (VDAC1) overexpression alleviates cardiac fibroblast activation in cardiac fibrosis via regulating fatty acid metabolism

Cardiac fibrosis is characterized by the excessive deposition of extracellular matrix in the myocardium with cardiac fibroblast activation, leading to chronic cardiac remodeling and dysfunction. However, little is known about metabolic alterations in fibroblasts during cardiac fibrosis, and there is a lack of pharmaceutical treatments that target metabolic dysregulation. Here, we provided evidence that fatty acid β-oxidation (FAO) dysregulation contributes to fibroblast activation and cardiac fibrosis. With transcriptome, metabolome, and functional assays, we demonstrated that FAO was downregulated during fibroblast activation and cardiac fibrosis, and that perturbation of FAO reversely affected the fibroblast-to-myofibroblast transition. The decrease in FAO may be attributed to reduced long-chain fatty acid (LCFA) uptake. Voltage-dependent anion channel 1 (VDAC1), the main gatekeeper of the outer mitochondrial membrane (OMM), serves as the transporter of LCFA into the mitochondria for further utilization and has been shown to be decreased in myofibroblasts. In vitro, the addition of exogenous VDAC1 was shown to ameliorate cardiac fibroblast activation initiated by transforming growth factor beta 1 (TGF-β1) stimuli, and silencing of VDAC1 displayed the opposite effect. A mechanistic study revealed that VDAC1 exerts a protective effect by regulating LCFA uptake into the mitochondria, which is impaired by an inhibitor of carnitine palmitoyltransferase 1A. In vivo, AAV9-mediated overexpression of VDAC1 in myofibroblasts significantly alleviated transverse aortic constriction (TAC)-induced cardiac fibrosis and rescued cardiac function in mice. Finally, we treated mice with the VDAC1-derived R-Tf-D-LP4 peptide, and the results showed that R-Tf-D-LP4 prevented TAC-induced cardiac fibrosis and dysfunction in mice. In conclusion, this study provides evidence that VDAC1 maintains FAO metabolism in cardiac fibroblasts to repress fibroblast activation and cardiac fibrosis and suggests that the VDAC1 peptide is a promising drug for rescuing fibroblast metabolism and repressing cardiac fibrosis.

ABCD1 Transporter Deficiency Results in Altered Cholesterol Homeostasis.

X-linked adrenoleukodystrophy (X-ALD), the most common peroxisomal disorder, is caused by mutations in the peroxisomal transporter ABCD1, resulting in the accumulation of very long-chain fatty acids (VLCFA). Strongly affected cell types, such as oligodendrocytes, adrenocortical cells and macrophages, exhibit high cholesterol turnover. Here, we investigated how ABCD1 deficiency affects cholesterol metabolism in human X-ALD patient-derived fibroblasts and CNS tissues of Abcd1-deficient mice. Lipidome analyses revealed increased levels of cholesterol esters (CE), containing both saturated VLCFA and mono/polyunsaturated (V)LCFA. The elevated CE(26:0) and CE(26:1) levels remained unchanged in LXR agonist-treated Abcd1 KO mice despite reduced total C26:0. Under high-cholesterol loading, gene expression of SOAT1, converting cholesterol to CE and lipid droplet formation were increased in human X-ALD fibroblasts versus healthy control fibroblasts. However, the expression of NCEH1, catalysing CE hydrolysis and the cholesterol transporter ABCA1 and cholesterol efflux were also upregulated. Elevated Soat1 and Abca1 expression and lipid droplet content were confirmed in the spinal cord of X-ALD mice, where expression of the CNS cholesterol transporter Apoe was also elevated. The extent of peroxisome-lipid droplet co-localisation appeared low and was not impaired by ABCD1-deficiency in cholesterol-loaded primary fibroblasts. Finally, addressing steroidogenesis, progesterone-induced cortisol release was amplified in X-ALD fibroblasts. These results link VLCFA to cholesterol homeostasis and justify further consideration of therapeutic approaches towards reducing VLCFA and cholesterol levels in X-ALD.

Immunometabolism changes in fibrosis: from mechanisms to therapeutic strategies.

Immune cells are essential for initiating and developing the fibrotic process by releasing cytokines and growth factors that activate fibroblasts and promote extracellular matrix deposition. Immunometabolism describes how metabolic alterations affect the function of immune cells and how inflammation and immune responses regulate systemic metabolism. The disturbed immune cell function and their interactions with other cells in the tissue microenvironment lead to the origin and advancement of fibrosis. Understanding the dysregulated metabolic alterations and interactions between fibroblasts and the immune cells is critical for providing new therapeutic targets for fibrosis. This review provides an overview of recent advances in the pathophysiology of fibrosis from the immunometabolism aspect, highlighting the altered metabolic pathways in critical immune cell populations and the impact of inflammation on fibroblast metabolism during the development of fibrosis. We also discuss how this knowledge could be leveraged to develop novel therapeutic strategies for treating fibrotic diseases.

Autophagy modulators influence the content of important signalling molecules in PS-positive extracellular vesicles

Extracellular vesicles (EVs) are important mediators of intercellular communication in the tumour microenvironment. Many studies suggest that cancer cells release higher amounts of EVs exposing phosphatidylserine (PS) at the surface. There are lots of interconnections between EVs biogenesis and autophagy machinery. Modulation of autophagy can probably affect not only the quantity of EVs but also their content, which can deeply influence the resulting pro-tumourigenic or anticancer effect of autophagy modulators. In this study, we found that autophagy modulators autophinib, CPD18, EACC, bafilomycin A1 (BAFA1), 3-hydroxychloroquine (HCQ), rapamycin, NVP-BEZ235, Torin1, and starvation significantly alter the composition of the protein content of phosphatidylserine-positive EVs (PS-EVs) produced by cancer cells. The greatest impact had HCQ, BAFA1, CPD18, and starvation. The most abundant proteins in PS-EVs were proteins typical for extracellular exosomes, cytosol, cytoplasm, and cell surface involved in cell adhesion and angiogenesis. PS-EVs protein content involved mitochondrial proteins and signalling molecules such as SQSTM1 and TGFβ1 pro-protein. Interestingly, PS-EVs contained no commonly determined cytokines, such as IL-6, IL-8, GRO-α, MCP-1, RANTES, and GM-CSF, which indicates that secretion of these cytokines is not predominantly mediated through PS-EVs. Nevertheless, the altered protein content of PS-EVs can still participate in the modulation of the fibroblast metabolism and phenotype as p21 was accumulated in fibroblasts influenced by EVs derived from CPD18-treated FaDu cells. The altered protein content of PS-EVs (data are available via ProteomeXchange with identifier PXD037164) also provides information about the cellular compartments and processes that are affected by the applied autophagy modulators.AbyDEs_V2PATMNaEJqximCVideo

Abstract LB039: Ovarian cancer cell-derived exosomal UCA1 reprograms glucose metabolism in stromal fibroblasts

Abstract Tumor progression is stringently regulated by the co-ordinated signaling between the tumor cells and the tumor microenvironment (TME) through diverse autocrine, paracrine and exocrine signaling mechanisms. Recent studies have shown that the exosomes that play a crucial role in the transfer of oncogenic macromolecules and oncometabolites to different cellular components of the TME can be targeted for therapy. Therefore, with the focus on identifying the exosomal long non-coding RNA (lncRNA) that can be therapeutically targeted, we investigated the profile of ovarian cancer cell derived lncRNAs and their functional role in ovarian cancer pathophysiology. Analysis of exosomes derived from a panel of high grade serous ovarian cancer cell lines indicated that UCA1 (Urothelial Cancer Associated 1) is the most abundantly packaged lncRNA in the exosomes. Similarly, exosomes from patient-derived ovarian cancer cells exhibited higher levels of UCA1. Ascites from ovarian cancer patients also indicated high levels of UCA1 in the ascites-derived exosomes. Results using PKH67-labelled ovarian cancer cell-derived exosomes and MRC5 fibroblast cell line indicated the exosomal transfer of UCA1 to the fibroblasts. Since paracrine signaling has been shown to induce metabolic reprogramming of peritumoral fibroblasts, we interrogated whether exosomal transfer of UCA1 could reprogram the glucose metabolism in the fibroblasts. Results from the Agilent Seahorse glycolytic stress assay indicate that the exosomal UCA1 promotes reprogramming of glucose metabolism in fibroblast cells while depleting of UCA1 in the exosomes failed to induce such metabolic reprogramming. Results from the analysis of the key glycolytic enzymes in the stromal fibroblasts, post-exosomal UCA1 uptake also corroborate this conclusion. Thus our results provide primary evidence that the exosomal-UCA1 induces pro-tumorigenic metabolic reprogramming in peri-tumoral fibroblasts. Together with the known oncogenic role of UCA1 in many different cancer cells, our findings indicate that targeting UCA1 could form a productive precision cancer strategy in ovarian cancer, targeting both the tumor cells and tumor stromal cells. This research was supported by the Department of Defense Ovarian Cancer Research Program Award W81XWH-18-1-0066, W81XWH-22-1-0415, the National Institute of General Medical Sciences grant P20 GM103639 and The National Cancer Institute of the National Institutes of Health grant P30 CA225520. Citation Format: Revathy Nadhan, Ji Hee Ha, Muralidharan Jayaraman, Srishti Kashyap, Danny N. Dhanasekaran. Ovarian cancer cell-derived exosomal UCA1 reprograms glucose metabolism in stromal fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB039.