Origin Of Myofibroblasts Research Articles

The Dynamic Role Of Myofibroblasts In Oral Tissue Homeostasis And Disease

Myofibroblasts are specialized cells that play a crucial role in maintaining the structural integrity and function of oral tissues. These cells exhibit a unique phenotype marked by the expression of alpha-smooth muscle actin (α-SMA), and possess the ability to contract and produce extracellular matrix components. In healthy oral tissues, myofibroblasts contribute to tissue homeostasis by mediating wound healing, tissue remodeling, and matrix turnover. However, the dysregulation of myofibroblast function can lead to pathological conditions such as fibrosis, scarring, and oral cancer. This review aims to explore the dynamic role of myofibroblasts in oral tissue homeostasis and disease. It begins by examining the origin of myofibroblasts in the oral cavity, their phenotypic characteristics, and their interactions with other cell types, including epithelial cells, immune cells, and endothelial cells. The review further highlights the role of myofibroblasts in various oral diseases, such as oral submucous fibrosis, periodontal disease, and oral cancer, and discusses potential therapeutic strategies targeting myofibroblast function. Understanding the dynamic role of myofibroblasts in oral tissue homeostasis and disease is essential for developing innovative therapeutic approaches to modulate myofibroblast function and improve the management of oral diseases.

New tools to study renal fibrogenesis.

Kidney fibrosis is a key pathological aspect and outcome of chronic kidney disease (CKD). The advent of multiomic analyses using human kidney tissue, enabled by technological advances, marks a new chapter of discovery in fibrosis research of the kidney. This review highlights the rapid advancements of single-cell and spatial multiomic techniques that offer new avenues for exploring research questions related to human kidney fibrosis development. We recently focused on understanding the origin and transition of myofibroblasts in kidney fibrosis using single-cell RNA sequencing (scRNA-seq) [1] . We analysed cells from healthy human kidneys and compared them to patient samples with CKD. We identified PDGFRα+/PDGFRβ+ mesenchymal cells as the primary cellular source of extracellular matrix (ECM) in human kidney fibrosis. We found several commonly shared cell states of fibroblasts and myofibroblasts and provided insights into molecular regulators. Novel single-cell and spatial multiomics tools are now available to shed light on cell lineages, the plasticity of kidney cells and cell-cell communication in fibrosis. As further single-cell and spatial multiomic approaches are being developed, opportunities to apply these methods to human kidney tissues expand similarly. Careful design and optimisation of the multiomic experiments are needed to answer questions related to cell lineages, plasticity and cell-cell communication in kidney fibrosis.

Morphological and immunohistochemical features can potentially help with the differential diagnosis of rare oral mesenchymal tumors

ObjectiveThe aim of this study was to evaluate the features of rare oral and maxillofacial benign and malignant tumors of fibroblastic, myofibroblastic and fibrohistiocytic origin in an attempt to contribute to the diagnosis of these tumors. MethodsThe sample consisted of 16 cases of benign fibrohistiocytic (BFH) tumor, myofibroma (MF), solitary fibrous tumor (SFT), fibrosarcoma (FS), dermatofibrosarcoma protuberans (DFSP), and myofibroblastic sarcoma (MFS), obtained from a laboratory of oral pathology. They were submitted to morphological, histochemical (Masson’s trichrome), and immunohistochemical (α-SMA, vimentin, desmin, CD34, Bcl-2, S100, CD68, CD99, and Ki-67) analysis. ResultsMorphological analysis revealed variable features in the tumors studied. Masson’s trichrome resulted in blue staining in most cases. Regarding the immunohistochemical features, all cases were positive for vimentin and negative for desmin. The BFH tumors exhibited positive staining for CD68 and S100, while MFs were positive for α-SMA and SFTs were positive for CD34, CD99 and Bcl-2. With respect to malignant tumors, DFSP was positive for CD34 and Bcl-2 and MFS was positive for α-SMA and Bcl-2, while FS was negative for most of the antibodies analyzed. A higher proliferation index (Ki-67) was observed in malignant tumors. ConclusionsConsidering their similarity, the use of auxiliary techniques might help in the differential diagnosis of these tumors.

Role of macrophage-to-myofibroblast transition in chronic liver injury and liver fibrosis

BackgroundChronic liver injury contributes to liver fibrosis, which is characterized by the excessive deposition of extracellular matrix (ECM) components. ECM is mainly composed of myofibroblasts. Recently, macrophage-to-myofibroblasts transition (MMT), has been identified as a novel origin for myofibroblasts. However, the potential functions of MMT in chronic liver injury and liver fibrosis remain unknown.MethodsTo clarify the transformation of fibrotic cells in hepatic fibrosis, liver specimens were collected from people at different stages in the progression of hepatic fibrosis and stained with immunofluorescence. Models of hepatic fibrosis such as the CCL4 model, HFD-induced NAFLD model, MCD-induced NAFLD model and ethanol-induced AFLD model were demonstrated and were stained with immunofluorescence.ResultsHere, we uncovered macrophages underwent MMT in clinical liver fibrosis tissue samples and multiple animal models of chronic liver injury. MMT cells were found in specimens from patients with liver fibrosis on the basis of co-expression of macrophage (CD68) and myofibroblast (a-SMA) markers. Moreover, macrophages could transform into myofibroblasts in CCL4-induced liver fibrosis model, high-fat diet (HFD) and methionine-choline-deficient diet (MCD)-induced nonalcoholic fatty liver diseases (NAFLD) model, and ethanol-induced alcoholic fatty liver diseases (AFLD) model. In addition, we highlighted that MMT cells mainly had a predominant M2 phenotype in both human and experimental chronic liver injury.ConclusionsTaken together, MMT acts a crucial role in chronic liver injury and liver fibrosis.

Infraorbital Myofibroma of Infra-orbital Region: A Rare Case Report

Introduction Infantile myofibroma is a rare tumor of myofibroblastic origin that can affect soft tissue, bones, or internal organs. The aim of the current study is to report a rare case of a solitary infra-orbital infantile myofibroma. Case presentation An 11-month-girl presented with progressive swelling of the left infra-ocular region for two weeks. On examination, there was a well-defined swelling with a localized border that was firm, non-mobile, tender, fixed to the underlying bone, and non-adherent to the superficial skin. Under general anesthesia, the right infraorbital mass was excised. The wound was closed by layers, and the histopathological examination revealed a 3 cm myofibroblastic mass that invaded the margins at multiple spots. Conclusion Infraorbital myofibroma is an extremely rare type of myofibroma. Excision with primary closure is the definitive management therapy.

NO-sensitive guanylyl cyclase discriminates pericyte-derived interstitial from intra-alveolar myofibroblasts in murine pulmonary fibrosis

BackgroundThe origin of αSMA-positive myofibroblasts, key players within organ fibrosis, is still not fully elucidated. Pericytes have been discussed as myofibroblast progenitors in several organs including the lung.MethodsUsing tamoxifen-inducible PDGFRβ-tdTomato mice (PDGFRβ-CreERT2; R26tdTomato) lineage of lung pericytes was traced. To induce lung fibrosis, a single orotracheal dose of bleomycin was given. Lung tissue was investigated by immunofluorescence analyses, hydroxyproline collagen assay and RT-qPCR.ResultsLineage tracing combined with immunofluorescence for nitric oxide-sensitive guanylyl cyclase (NO-GC) as marker for PDGFRβ-positive pericytes allows differentiating two types of αSMA-expressing myofibroblasts in murine pulmonary fibrosis: (1) interstitial myofibroblasts that localize in the alveolar wall, derive from PDGFRβ+ pericytes, express NO-GC and produce collagen 1. (2) intra-alveolar myofibroblasts which do not derive from pericytes (but express PDGFRβ de novo after injury), are negative for NO-GC, have a large multipolar shape and appear to spread over several alveoli within the injured areas. Moreover, NO-GC expression is reduced during fibrosis, i.e., after pericyte-to-myofibroblast transition.ConclusionIn summary, αSMA/PDGFRβ-positive myofibroblasts should not be addressed as a homogeneous target cell type within pulmonary fibrosis.

#3685 PERICYTE AND CXCL12 PLAY CRUCIAL ROLE IN THE RECOVERY OF ACUTE KIDNEY INJURY

Abstract Background and Aims Pericytes are mesenchyme-derived perivascular cells attached to the abluminal surface of capillaries as well as the major origin of myofibroblasts in the animal model of unilateral ureteral obstruction (UUO) and ischemia-reperfusion injury (IRI). Although previous studies reported that myofibroblasts may be beneficial during acute kidney injury (AKI) via growth factor secretion, reconstitution and stabilization of the collagen framework for tubular cell regeneration, lack of solid evidence and definite mechanism make the role of pericyte/myofibroblast in AKI remain controversial. Method To clarify this, we used platelet-derived growth factor receptor β (PDGFRβ)-specific antibody following AKI in C57BL/6 mice to inhibit pericytes. In the meantime, We used Gli1-CreERT2;Cxcl12fl/fl genetically modified mice to conditionally knockout CXCL12 specifically in pericytes before IRI. Results The expression of PDGFRβ on pericytes increased after IRI. In group of administration of PDGFRβ antibody, proliferation and transition to myofibroblasts of pericytes were inhibited. Inflammation became worse and renal recovery was impeded after AKI. The chemokine stromal cell-derived factor-1 (SDF-1) which is also known as the C-X-C-type chemokine CXCL12 decreased as well. Furthermore, we demonstrated that CXCL12 was secreted mainly by pericytes and its receptor CXCR4 was expressed on tubular cell during IRI by in situ hybridization. When knockout of CXCL12 was performed before IRI, the renal microvascular rarefaction was noted after AKI and the recovery of renal function was impaired. Renal tubular cell proliferation decreased and apoptosis increased as well. Conclusion In summary, these findings demonstrated that pericytes contribute to renal repair after IRI through CXCL12 secretion.

Wound infiltrating adipocytes are not myofibroblasts

The origins of wound myofibroblasts and scar tissue remains unclear, but it is assumed to involve conversion of adipocytes into myofibroblasts. Here, we directly explore the potential plasticity of adipocytes and fibroblasts after skin injury. Using genetic lineage tracing and live imaging in explants and in wounded animals, we observe that injury induces a transient migratory state in adipocytes with vastly distinct cell migration patterns and behaviours from fibroblasts. Furthermore, migratory adipocytes, do not contribute to scar formation and remain non-fibrogenic in vitro, in vivo and upon transplantation into wounds in animals. Using single-cell and bulk transcriptomics we confirm that wound adipocytes do not convert into fibrogenic myofibroblasts. In summary, the injury-induced migratory adipocytes remain lineage-restricted and do not converge or reprogram into a fibrosing phenotype. These findings broadly impact basic and translational strategies in the regenerative medicine field, including clinical interventions for wound repair, diabetes, and fibrotic pathologies.

Neutralization of excessive levels of active TGF-β1 reduces MSC recruitment and differentiation to mitigate peritendinous adhesion

Peritendinous adhesion formation (PAF) can substantially limit the range of motion of digits. However, the origin of myofibroblasts in PAF tissues is still unclear. In this study, we found that the concentration of active TGF-β1 and the numbers of macrophages, mesenchymal stromal cells (MSCs), and myofibroblasts in human and mouse adhesion tissues were increased. Furthermore, knockout of TGF-β1 in macrophages or TGF-β1R2 in MSCs inhibited PAF by reducing MSC and myofibroblast infiltration and collagen I and III deposition, respectively. Moreover, we found that MSCs differentiated into myofibroblasts to form adhesion tissues. Systemic injection of the TGF-β–neutralizing antibody 1D11 during the granulation formation stage of PAF significantly reduced the infiltration of MSCs and myofibroblasts and, subsequently, PAF. These results suggest that macrophage-derived TGF-β1 recruits MSCs to form myofibroblasts in peritendinous adhesions. An improved understanding of PAF mechanisms could help identify a potential therapeutic strategy.

Origins of pathological myofibroblasts in lung fibrosis: insights from lineage tracing mouse models in the single-cell RNA sequencing era.

Idiopathic pulmonary fibrosis (IPF) is a rare interstitial lung disease with a poor prognosis. Chronic microinjuries, mainly caused by environmental factors to an aging alveolar epithelium, would lead to the aberrant differentiation and accumulation of aberrant mesenchymal cells with a contractile phenotype, known as fibrosis-associated myofibroblasts, which trigger abnormal extracellular matrix accumulation and fibrosis. The origin of those pathological myofibroblasts in pulmonary fibrosis is not fully understood to date. Lineage tracing methods using mouse models have opened new avenues for studying cell fate in a pathological context. This review aims to present a nonexhaustive list of different potential sources of those harmful myofibroblasts during lung fibrosis, based on these in vivo approaches, and considering the normal and fibrotic lung cellular atlas recently established by single-cell RNA sequencing.

Therapeutic effects of TMF and catechol in pulmonary fibrosis: in vitro and in vivo analysis

Idiopathic pulmonary fibrosis is a fatal lung disorder characterized by abnormal deposition of extracellular matrix (ECM), which is secreted by activated myofibroblasts. While the origin of myofibroblasts has been discussed, epithelial-mesenchymal transition (EMT) is being noticed as one of the mechanisms of myofibroblast activation. Recent studies have shown that reactive oxygen species appear to induce not only EMT but also fibrotic progression and maintenance. Therefore, we tested chemicals that have antioxidant capacity as drugs for fibrosis. To evaluate the effects of 4′,6,7-trimethoxyisoflavone (TMF) and catechol (CAT) on EMT and fibrosis, we used an in vitro transforming growth factor (TGF)-β1 or bleomycin-induced model and an in vivo BLM-induced model. The results showed that the co-administration of TMF/CAT ameliorated pulmonary fibrosis by decreasing EMT and ECM accumulation by hindering both Smad and non-Smad TGF-β signalling cascades. Furthermore, significant increases in the number of total immune cells (especially lymphocytes) were observed in BLM-treated animals treated with TMF/CAT. Our findings suggest that co-intervention with TMF/CAT may be a potential treatment for fibrosis.

Solitary, adult-onset, intraosseous myofibroma of the rib: a case report and literature review

Myofibromas are rare benign tumors with myofibroblastic origin. They occur especially in cutis and subcutaneous tissue of the head and the neck, less frequently on the extremities. Myofibromas grow very slowly and are often painless, which is why patients often present relatively late. In the literature, there were many reports about intraosseous myofibromas of the craniofascial bones but reports of the trunk and extremities in adults are very rare. The authors present a very rare case of an intraosseous myofibroma of the ribs resulting in pathological fracture, including a research of literature from other cases of intraosseous myofibromas of the trunk or extremities.

Mandibular Solitary Intraosseous Myofibroma: A Case Report and Review of Literature

Abstract Introduction/Objective Myofibroma (MF) is a benign soft tissue neoplasm of myofibroblastic origin, which frequently occurs in children and rarely presents as an intraosseous neoplasm. Other benign mesenchymal lesions and other low-grade malignant soft tissue neoplasms mimic morphologically to MF, thus making the diagnosis of MF challenging and crucial. Methods/Case Report Herein, we describe a 9-year-old female who was referred to an oral surgeon by her dentist, for evaluation of a radiolucent lesion on her left mandible associated with impacted tooth #21 and 22, which had slightly increased in size over 2 weeks. Her medical history was non-contributory other than asthma. Clinical examination revealed a large 5x4 cm firm mass slightly tender and causing expansion along the buccal as well as lingual aspects of the mandible in the canine and first premolar region. A radiograph CBCT of the mandible revealed malposed tooth #21 and 22 and unilocular radiolucency associated with the crowns #21 and 22. No evidence of calcifications within the lucency was noted. The patient underwent an incisional biopsy of the mandibular lesion, which showed a benign tumor composed of bland spindled cells arranged in fascicles with scattered thin walled blood vessels. Mitotic figures were inconspicuous and there was no discernible necrosis. Immunohistochemical stains show that the lesional cells are positive for SMA and Vimentin (Fig. 1 A-D, H&E, SMA, Ki-67, Vimentin) and negative for S100, desmin and CD34. Ki-67 (proliferative index) is interpreted to be low (<5%). Results (if a Case Study enter NA) NA Conclusion Mandibular intraosseous MF is extremely rare. Clinico-pathologic correlation, immunohistochemical features and sometimes molecular studies are essential for correct diagnosis and to rule out other benign and low-grade soft tissue neoplasms that mimic MF morphologically and radiographically. Thus MF, though rare neoplasm should be considered in the differential diagnosis of unilocular or multilocular radiolucent lesions of the jaws.

Cardiac Inflammatory Myofibroblastic Tumours in Three Young Adult Cats

Inflammatory myofibroblastic tumours (IMTs) of the heart are described in three young adult cats (case 1, 3.5 years old; case 2, 2.7 years old; case 3, 1.8 years old) that died due to pleural and pericardial effusions resulting from congestive heart failure. At necropsy, cardiac masses, measuring 4×3×2.5cm (case 1), 3.5×2.5×2cm (case 2) and 3×2.5×2cm (case 3), were located mainly in the right auricle (case 1) and atrial septum (cases 2 and 3) with variable extension into the surrounding tissue. Histologically, the atrial masses in all three cats comprised proliferation of spindloid mesenchymal cells and an inflammatory infiltrate of plasma cells and lymphocytes in variable amounts of myxoid background. The spindloid cells were uniform and characterized by pale eosinophilic cytoplasm and a vesicular nucleus containing prominent nucleoli, with no remarkable cytological atypia or mitotic activity. Immunohistochemically, these cells were positive for vimentin and α-smooth muscle actin in all cases, supporting a myofibroblastic origin. The histopathological and immunohistochemical features were consistent with those of IMTs in humans and animals. There have been no previous reports of such tumours occurring in the heart of the cat.

The Role of Mesothelin in Activation of Portal Fibroblasts in Cholestatic Liver Injury.

Fibrosis is a common consequence of abnormal wound healing, which is characterized by infiltration of myofibroblasts and formation of fibrous scar. In liver fibrosis, activated Hepatic Stellate Cells (aHSCs) and activated Portal Fibroblasts (aPFs) are the major contributors to the origin of hepatic myofibroblasts. aPFs are significantly involved in the pathogenesis of cholestatic fibrosis, suggesting that aPFs may be a primary target for anti-fibrotic therapy in cholestatic injury. aPFs are distinguishable from aHSCs by specific markers including mesothelin (Msln), Mucin 16 (Muc16), and Thymus cell antigen 1 (Thy1, CD90) as well as fibulin 2, elastin, Gremlin 1, ecto-ATPase nucleoside triphosphate diphosphohydrolase 2. Msln plays a critical role in activation of PFs, via formation of Msln-Muc16-Thy1 complex that regulates TGFβ1/TGFβRI-mediated fibrogenic signaling. The opposing pro- and anti-fibrogenic effects of Msln and Thy1 are key components of the TGFβ1-induced activation pathway in aPFs. In addition, aPFs and activated lung and kidney fibroblasts share similarities across different organs with expression of common markers and activation cascade including Msln-Thy1 interaction. Here, we summarize the potential function of Msln in activation of PFs and development of cholestatic fibrosis, offering a novel perspective for anti-fibrotic therapy targeting Msln.

MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL FINDINGS OF UNUSUAL ORAL MESENCHYMAL TUMORS

<h3>Objectives</h3> To evaluate the features of uncommon oral benign and malignant tumors of fibroblastic, myofibroblastic, and fibrohistiocytic origin to better understand the diagnostic challenges of these tumors. <h3>Study Design</h3> This study evaluated benign fibrohistiocytic tumor (BFH; <i>n</i> = 4), myofibroma (MF; <i>n</i> = 2), solitary fibrous tumor (SFT; <i>n</i> = 6), fibrosarcoma (FS; <i>n</i> = 2), dermatofibrosarcoma protuberans (DFSP; <i>n</i> = 1), and myofibroblastic sarcoma (MFS; <i>n</i> = 1) obtained from a diagnostic service. We carried out morphologic and immunohistochemical (αSMA, vimentin, desmin, CD34, Bcl2, S100, CD68, CD99) analyses. <h3>Results</h3> Morphologic analysis showed several features in tumor cells and stroma of the tumors (multinucleated cells, clear cells, hypercellular and hypocellular areas). Immunohistochemistry demonstrated that all cases were positive for vimentin and negative for desmin. BFH tumors exhibited immunopositivity for CD68 and S100, whereas MFs were positive for αSMA and SFTs for CD34, CD99, and Bcl2. Regarding malignant tumors, DFSP was positive for CD34 and Bcl2, and MFS was positive for αSMA and Bcl2, whereas FS was negative for most of the antibodies analyzed. Furthermore, malignant tumors exhibit a higher proliferation index (Ki-67 > 10%). <h3>Conclusions</h3> Considering their morphologic similarity, the use of immunohistochemistry is of great value to help in the differential diagnosis of these tumors.

IMMUNOHISTOCHEMICAL MARKERS FOR THE DIAGNOSIS OF ORAL SPINDLE CELL LESIONS: A REVIEW

<h3>Objectives</h3> To review the useful immunohistochemical markers in the diagnosis of spindle cell lesions of the oral cavity. <h3>Study Design</h3> A narrative review of the literature was carried out in PubMed and Portal Periódicos CAPES databases. Immunohistochemical profiles of myofibroblastic (myofibroma, inflammatory myofibroblastic tumor, low-grade myofibroblastic sarcoma), fibroblastic (solitary fibrous tumor, fibromatosis, nodular fasciitis, fibrosarcoma), and muscular (leiomyoma, angioleiomyoma, leiomyosarcoma) lesions was collected. <h3>Results</h3> A graphic summary of the results was elaborated. Of notice, h-caldesmon and smooth muscle myosin are helpful to differentiate myofibroblastic and muscular lesions. CD34, bcl-2, and CD99 are useful for diagnosing solitary fibrous tumor. The lack of desmin expression in myofibroma may help in the differentiation from leiomyoma. p53 and Ki-67 may help in the diagnosis of malignant lesions. <h3>Conclusions</h3> Immunohistochemistry is often useful to stablish the histopathologic diagnosis of oral spindle cell lesions of myofibroblastic, fibroblastic, and muscular origin, though a large panel can be necessary. H-caldesmon, smooth muscle actin, smooth muscle myosin, desmin, and muscle-specific actin are of great importance. Other markers such as CD99 and ALK-1 are useful for specific lesions.

P36-12 A case of progressing mesenteric desmoid fibromatosis: A diagnostic and therapeutic challenge

Desmoid fibromatoses are rare, benign neoplasms of myofibroblast origin that lack metastatic potential but can be locally invasive. Diagnosis and management is challenging as it is based on factors such as symptomatology, tumor location, risk or recurrence and the possibility of treatment-induced morbidity.

NHE1 as a Target to Block Lung Fibrosis Progression

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing interstitial pneumonia of unknown origin. Fibrosis, a wound healing process, occurs when fibroblasts increase proliferation, convert to myofibroblasts, and secrete extracellular matrix (ECM) proteins. As a result, tissue becomes scarred, reducing lung compliance and ultimately leads to organ dysfunction and death. IFP is characterized by profibrotic agonists and alpha‐smooth muscle actin (α‐SMA) expression. TGF‐β, IL‐1β, LPA, 5‐HT are agonists involved in cell migration regulation, proliferation, and cytokine production. Chronic agonists exposure causes α‐SMA expression which stiffens fibrotic tissue alongside ECM proteins. Prior studies have shown that the sodium hydrogen exchanger isoform 1 (NHE1) is a key regulator in cell migration and pathophysiological development of cancer. The characteristics of IFP are similar to that of cancer (i.e., response to growth signals, myofibroblast origin and behavior, altered cellular communications, and intercellular signaling pathways). Due to these similarities, we hypothesize that NHE1 plays a key role in IFP progression. Results show fibroblast to myofibroblast differentiation is induced in the presence of NHE1 and can also be blocked by the NHE1 inhibitor (EIPA) in mammalian hamster cells. Cells treated with agonists showed some to high α‐SMA expression. Cells treated with agonist and EIPA had no expression of α‐SMA (TGF‐β/EIPA: 35.67 ± 1.76; IL‐1β/EIPA: 11.67 ± 2.03, LPA/EIPA: 33.33 ± 2.19, 5HT/EIPA: 30.00 ± 1.15), and is comparable to the untreated control (20.83 ± 3.12). This improves our understanding of NHE1's role in IPF, and how NHE1 can be a target to impede or hopefully reverse myofibroblast differentiation in IPF patients.

Mesenchymal Stem Cells Ameliorate Fibrosis by Enhancing Autophagy via Inhibiting Galectin-3/Akt/mTOR Pathway and by Alleviating the EMT via Inhibiting Galectin-3/Akt/GSK3β/Snail Pathway in NRK-52E Fibrosis.

Epithelial-Mesenchymal transition (EMT) is one of the origins of myofibroblasts in renal interstitial fibrosis. Mesenchymal stem cells (MSCs) alleviating EMT has been proved, but the concrete mechanism is unclear. To explore the mechanism, serum-free MSCs conditioned medium (SF-MSCs-CM) was used to treat rat renal tubular epithelial cells (NRK-52E) fibrosis induced by transforming growth factor-β1 (TGF-β1) which ameliorated EMT. Galectin-3 knockdown (Gal-3 KD) and overexpression (Gal-3 OE) lentiviral vectors were established and transfected into NRK-52E. NRK-52E fibrosis model was induced by TGF-β1 and treated with the SF-MSCs-CM for 24 h after modelling. Fibrosis and autophagy related indexes were detected by western blot and immunocytochemistry. In model group, the expressions of α-smooth muscle actin (α-SMA), fibronectin (FN), Galectin-3, Snail, Kim-1, and the ratios of P-Akt/Akt, P-GSK3β/GSK3β, P-PI3K/PI3K, P-mTOR/mTOR, TIMP1/MMP9, and LC3B-II/I were obviously increased, and E-Cadherin (E-cad) and P62 decreased significantly compared with control group. SF-MSCs-CM showed an opposite trend after treatment compared with model group. Whether in Gal-3 KD or Gal-3 OE NRK-52E cells, SF-MSCs-CM also showed similar trends. However, the effects of anti-fibrosis and enhanced autophagy in Gal-3 KD cells were more obvious than those in Gal-3 OE cells. SF-MSCs-CM probably alleviated the EMT via inhibiting Galectin-3/Akt/GSK3β/Snail pathway. Meanwhile, Gal-3 KD possibly enhanced autophagy via inhibiting Galectin-3/Akt/mTOR pathway, which synergistically ameliorated renal fibrosis. Targeting galectin-3 may be a potential target for the treatment of renal fibrosis.