Managing Temporomandibular Joint Osteoarthritis by Dental Stem Cell Secretome

The potential therapeutic role of the Dental Pulp Stem Cells Secretome (SECR) in a rat model of experimentally induced Temporomandibular Joint (TMJ) Osteoarthritis (OA) was evaluated. Proteomic profiling of the human SECR under specific oxygen tension (5% O2) and stimulation with Tumor Necrosis Factor-alpha (TNF-α) was performed. SECR and respective cell lysates (CL) samples were collected and subjected to SDS-PAGE, followed by LC-MS/MS analysis. The identified proteins were analyzed with Bioinformatic tools. The anti-inflammatory properties of SECR were assessed via an in vitro murine macrophages model, and were further validated in vivo, in a rat model of chemically-induced TMJ-OA by weekly recording of the head withdrawal threshold, the food intake, and the weight change, and radiographically and histologically at 4- and 8-weeks post-treatment. SECR analysis revealed the presence of 50 proteins that were enriched and/or statistically significantly upregulated compared to CL, while many of those proteins were involved in pathways related to "extracellular matrix organization" and "immune system". SECR application in vitro led to a significant downregulation on the expression of pro-inflammatory genes (MMP-13, MMP-9, MMP-3 and MCP-1), while maintaining an increased expression of IL-10 and IL-6. SECR application in vivo had a significant positive effect on all the clinical parameters, resulting in improved food intake, weight, and pain suppression. Radiographically, SECR application had a significant positive effect on trabecular bone thickness and bone density compared to the saline-treated group. Histological analysis indicated that SECR administration reduced inflammation, enhanced ECM and subchondral bone repair and regeneration, thus alleviating TMJ degeneration.

Research progress and application prospect of adipose-derived stem cell secretome in diabetes foot ulcers healing

Diabetic foot ulcers (DFUs) are chronic wounds and one of the most common complications of diabetes, imposing significant physical and mental burdens on patients due to their poor prognosis and treatment efficacy. Adipose-derived stem cells (ADSCs) have been proven to promote wound healing, with studies increasingly attributing these beneficial effects to their paracrine actions. Consequently, research on ADSC secretome as a novel and promising alternative for DFU treatment has been extensively conducted. This article provides a comprehensive review of the mechanisms underlying refractory DFU wounds, the secretome of ADSCs, and its role in promoting wound healing in diabetes foot ulcers. And the review aims to provide reliable evidence for the clinical application of ADSC secretome in the treatment of refractory DFU wounds.

Proteomic analysis of the human amniotic mesenchymal stromal cell secretome by integrated approaches via filter-aided sample preparation

The immunomodulatory, anti-inflammatory and regenerative properties of the human amniotic mesenchymal stromal cells (hAMSCs) secretome are acknowledged but the understanding of the specific bioactive components remains incomplete. To address these limitations, the present investigation aimed to profile the proteins and peptides content of the hAMSC secretome through sample pretreatment and fractionation on 10 kDa molecular cut-off FASP (Filter Aided Sample Preparation) device and LC-MS analysis. The filter retained protein fraction underwent trypsin digestion, while the unretained was collected unchanged for intact small proteins and peptides analysis. This combined approach (C-FASP) collects in a single step two complementary fractions, advantageously saving sample volume and time of analysis. The bottom-up analysis of the C-FASP proteins fraction >10 kDa confirmed our previous findings, establishing a set of proteins consistently characterizing the hAMSC secretome. The analysis of the fraction <10 kDa, never been investigated to our knowledge, identified peptide fragments of thymosin beta 4 and beta 10, collagen alpha 1 chains I and III, alpha-enolase, and glyceraldehyde-3-phosphate dehydrogenase, involved in wound healing, anti-inflammatory response, tissue repair and regeneration, key biological activities of the secretome. C-FASP provided a comprehensive molecular profile of the hAMSC secretome offering new insights for enhanced therapeutic applications in regenerative medicine. SIGNIFICANCE: In this investigation we originally present the comprehensive proteomic investigation of the human amniotic mesenchymal stromal cell secretome by combining the analysis of the proteome and of the peptidome following sample pretreatment and fractionation by Filter Aided Sample Preparation (FASP) with 10 kDa molecular cut-off in coupling with LC-MS analysis. The proteome fraction retained by FASP filter was analyzed after enzymatic digestion, while the unretained fraction, below 10 kDa molecular mass, was analyzed unchanged in its intact form. This dual approach provides novel insights, previously unexplored, into the molecular components potentially responsible for the immunomodulatory and anti-inflammatory properties of the hAMSC secretome. These findings could significantly enhance the therapeutic potential of hAMSCs in regenerative medicine.

Profiling the Secretome of Glioblastoma Cells Under Histone Deacetylase Inhibition Using Mass Spectrometry

Glioblastoma (GBM) is the most aggressive brain tumor, and different efforts have been employed in the search for new drugs and therapeutic protocols for GBM. A label-free, mass spectrometry-based quantitative proteomics has been developed to identify and characterize proteins that are differentially expressed in GBM to gain a better understanding of the interactions and functions that lead to the pathological state focusing on the extracellular matrix (ECM). The main challenge in GBM research has been to identify novel molecular therapeutic targets and accurate diagnostic/prognostic biomarkers. To better investigate the GBM secretome upon in vitro treatment with histone deacetylase inhibitor (iHDAC), we employed a high-throughput label-free methodology of protein identification and quantification based on mass spectrometry followed by in silico studies. Our analysis revealed significant changes in the ECM protein profile, particularly those associated with the angiogenic matrisome. Proteins such as decorin, ADAM10, ADAM12, and ADAM15 were differentially regulated upon in silico analysis. In contrast, key angiogenesis markers such as VEGF and ECM proteins like fibronectin and integrins did not display significant changes. These results suggest that iHDAC inhibitors may modulate or suppress tumor behavior growth by targeting ECM proteins' secretion rather than directly inhibiting angiogenesis. Key features • Analysis of the secretome of U87MG glioblastoma cells. • Studies of mass spectrometry designed to modulate GBM biology and behavior focused on histone deacetylase inhibitors (iHDAC). • Mass spectrometry was developed to identify and characterize proteins that are differentially expressed in GBM.

Flagellin, a plant-defense-activating protein identified from Xanthomonas axonopodis pv. Dieffenbachiae invokes defense response in tobacco

BACKGROUND

Secretome analysis is a valuable tool to study host-pathogen protein interactions and to identify new proteins that are important for plant health. Microbial signatures elicit defense responses in plants, and by that, the plant immune system gets triggered prior to pathogen infection. Functional properties of secretory proteins from Xanthomonas axonopodis pv. dieffenbachiae (Xad1) involved in priming plant immunity was evaluated.

RESULTS

In this study, the secretome of Xad1 was analyzed under host plant extract-induced conditions, and mass spectroscopic analysis of differentially expressed protein was identified as plant-defense-activating protein viz., flagellin C (FliC). The flagellin and Flg22 peptides both elicited hypersensitive reaction (HR) in non-host tobacco, activated reactive oxygen species (ROS) scavenging enzymes, and increased pathogenesis-related (PR) gene expression viz., NPR1, PR1, and down-regulation of PR2 (β-1,3-glucanase). Protein docking studies revealed the Flg22 epitope of Xad1, a 22 amino acid peptide region in FliC that recognizes plant receptor FLS2 to initiate downstream defense signaling.

CONCLUSION

The flagellin or the Flg22 peptide from Xad1 was efficient in eliciting an HR in tobacco via salicylic acid (SA)-mediated defense signaling that subsequently triggers systemic immune response epigenetically. The insights from this study can be used for the development of bio-based products (small PAMPs) for plant immunity and health.

Secretome of Paenibacillus sp. S-12 provides an insight about its survival and possible pathogenicity

Our aim in this study was to characterize and investigate the secretome of Paenibacillus sp. S-12 by nanoLC-MS/MS tool-based analysis of trypsin digested culture supernatant proteins. Using a bioinformatics and combined approach of mass spectrometry, we identified 657 proteins in the secretome. Bioinformatic tools such as PREDLIPO, SecretomeP 2.0, SignalP 4.1, and PSORTb were used for the subcellular localization and categorization of secretome on basis of signal peptides. Among the identified proteins, more than 25% of the secretome proteins were associated with virulence proteins including flagellar, adherence, and immune modulators. Gene ontology analysis using Blast2GO tools categorized 60 proteins of the secretome into biological processes, cellular components, and molecular functions. KEGG pathway analysis identified the enzymes or proteins involved in various biosynthesis and degradation pathways. Functional analysis of secretomes reveals a large number of proteins involved in the uptake and exchange of nutrients, colonization, and chemotaxis. A good number of proteins were involved in survival and defense mechanism against oxidative stress, the production of toxins and antimicrobial compounds. The present study is the first report of the in-depth protein profiling of Paenibacillus bacterium. In summary, the current findings of Paenibacillus sp. S-12 secretome provide basic information to understand its survival and the possible pathogenic mechanism.

Extracellular proteins enhance Cupriavidus pauculus nickel tolerance and cell aggregate formation

Heavy metal-resistant bacteria secrete extracellular proteins (e-PNs). However, the role of e-PNs in heavy metal resistance remains elusive. Here Fourier Transform Infrared Spectroscopy implied that N-H, C = O and NH2-R played a crucial role in the adsorption and resistance of Ni2+ in the model organism Cuprividus pauculus 1490 (C. pauculus). Proteinase K treatment reduced Ni2+ resistance of C. pauculus underlining the essential role of e-PNs. Further three-dimension excitation-emission matrix fluorescence spectroscopy analysis demonstrated that tryptophan proteins as part of the e-PNs increased significantly with Ni2+ treatment. Proteomic and quantitative real-time polymerase chain reaction data indicated that major changes were induced in the metabolism of C. pauculus in response to Ni2+. Among those lipopolysaccharide biosynthesis, general secretion pathways, Ni2+-affiliated transporters and multidrug efflux play an essential role in Ni2+ resistance. Altogether the results provide a conceptual model for comprehending how e-PNs contribute to bacterial resistance and adsorption of Ni2+.

Frontiers in Plasma Proteome Profiling Platforms: Innovations and Applications

Biomarkers play a crucial role in advancing precision medicine by enabling more targeted and individualized approaches to diagnosis and treatment. Various biofluids, including serum, plasma, cerebrospinal fluid (CSF), saliva, tears, pancreatic cyst fluids, and urine, have been identified as rich sources of potential for the early detection of disease biomarkers in conditions such as cancer, cardiovascular diseases, and neurodegenerative disorders. The analysis of plasma and serum in proteomics research encounters challenges due to their high complexity and the wide dynamic range of protein abundance. These factors impede the sensitivity, coverage, and precision of protein detection when employing mass spectrometry, a widely utilized technology in discovery proteomics. Conventional approaches such as neat plasma workflow are inefficient in accurately quantifying low-abundant proteins, including those associated with tissue leakage, immune response molecules, interleukins, cytokines, and interferons. Moreover, the manual nature of the workflow poses a significant hurdle in conducting large cohort studies. In this study, our focus is on comparing workflows for plasma proteomic profiling to establish a methodology that is not only sensitive and reproducible but also applicable for large cohort studies in biomarker discovery. Our investigation revealed that the SeerProteographXT workflow outperforms other workflows in terms of plasma proteome depth, quantitative accuracy, and reproducibility while offering complete automation of sample preparation. Notably, SeerProteographXT demonstrates versatility by applying it to various types of biofluids. Additionally, the proteins quantified widely cover secretory proteins in peripheral blood, and the pathway analysis enriched with relevant components such as interleukins, tissue necrosis factors, chemokines, and B and T cell receptors provides valuable insights. These proteins, often challenging to quantify in complex biological samples, hold potential as early detection markers for various diseases, thereby contributing to the improvement of patient care quality.

Bidimensional Analyses of the Intra- and Extracellular Proteomes of Steroid Producer Mycobacteria

The importance of the pathogenic mycobacteria has mainly focused the omic analyses on different aspects of their clinical significance. However, those industrially relevant mycobacteria have received less attention, even though the steroid market sales in 2021 were estimated in $56.45 billion.The extracellular proteome, due to its relevance in the sterol processing and uptake, and the intracellular proteome, because of its role in steroids bioconversion, are the core of the present chapter. Both, monodimensional gels, as preparatory analysis, and bidimensional gels as proteome analysis are described. As a proof of concept, the protein extraction methods for both sub-proteomes of Mycobacterium are described. Thus, procedures and relevant key points of these proteome analyses are fully detailed.

Aspartyl protease in the secretome of honey bee trypanosomatid parasite contributes to infection of bees

BACKGROUND

The exoproteome, which consists of both secreted proteins and those originating from cell surfaces and lysed cells, is a critical component of trypanosomatid parasites, facilitating interactions with host cells and gut microbiota. However, its specific roles in the insect hosts of these parasites remain poorly understood.

METHODS

We conducted a comprehensive characterization of the exoproteome in Lotmaria passim, a trypanosomatid parasite infecting honey bees, under culture conditions. We further investigated the functions of two conventionally secreted proteins, aspartyl protease (LpAsp) and chitinase (LpCht), as representative models to elucidate the role of the secretome in L. passim infection of honey bees.

RESULTS

Approximately 48% of L. passim exoproteome proteins were found to share homologs with those found in seven Leishmania spp., suggesting the existence of a core exoproteome with conserved functions in the Leishmaniinae lineage. Bioinformatics analyses suggested that the L. passim exoproteome may play a pivotal role in interactions with both the host and its microbiota. Notably, the deletion of genes encoding two secretome proteins revealed the important role of LpAsp, but not LpCht, in L. passim development under culture conditions and its efficiency in infecting the honey bee gut.

CONCLUSIONS

Our results highlight the exoproteome as a valuable resource for unraveling the mechanisms employed by trypanosomatid parasites to infect insect hosts by interacting with the gut environment.

Double-layer dissolving microneedles for delivery of mesenchymal stem cell Secretome: Formulation, characterisation and skin irritation study

Regenerative therapy based on stem cells have been developed, focusing on either stem cell or secretome delivery. Most marketed cellular and gene therapy products are available as injectable dosage forms, leading to several limitations requiring alternative routes, such as the intradermal route. Microneedles, capable of penetratingthe stratum corneumbarrier, offer a potential alternative for intradermal delivery. This present study aimed to develop double-layer dissolving microneedles (DMN) for the delivery of freeze-dried mesenchymal stem cell secretome. DMNs were fabricated using a two-step casting method and composed of two polymer combinations: poly(vinyl pyrrolidone) (PVP) with poly(vinyl alcohol) (PVA) or PVP with sodium hyaluronate (SH). The manufactured DMNs underwent assessments for morphology, mechanical strength, in skin dissolution, protein content, in vitro permeation, in vivo skin irritation, and physical stability. Based on evaluations of morphology and mechanical strength, two formulas (F5 and F12) met acceptance criteria. Evaluation of protein content revealed that F12 (PVP-SH combination) had a higher protein content than F5 (PVP-PVA combination), 99.02 ± 3.24 μg and 78.36 ± 3.75 μg respectively. In vitro permeation studies showed that F5 delivered secretome protein by 100.84 ± 0.88%, while F12 delivered 99.63 ± 9.21% in 24 h. After four days of observation onSprague-Dawleyrat's skin, no signs of irritation, such as oedema and redness, was observed after applying both formulations. The safety of using PVP-PVA and PVP-SH combinations as excipients for DMN secretome delivery has been confirmed, promising significant advancements in biotherapeutic development in the future.

The secretome from human-derived mesenchymal stem cells augments the activity of antitumor plant extracts in vitro

Cancer is understood as a multifactorial disease that involve multiple cell types and phenotypes in the tumor microenvironment (TME). The components of the TME can interact directly or via soluble factors (cytokines, chemokines, growth factors, extracellular vesicles, etc.). Among the cells composing the TME, mesenchymal stem cells (MSCs) appear as a population with debated properties since it has been seen that they can both promote or attenuate tumor progression. For various authors, the main mechanism of interaction of MSCs is through their secretome, the set of molecules secreted into the extracellular milieu, recruiting, and influencing the behavior of other cells in inflammatory environments where they normally reside, such as wounds and tumors. Natural products have been studied as possible cancer treatments, appealing to synergisms between the molecules in their composition; thus, extracts obtained from Petiveria alliacea (Anamu-SC) and Caesalpinia spinosa (P2Et) have been produced and studied previously on different models, showing promising results. The effect of plant extracts on the MSC secretome has been poorly studied, especially in the context of the TME. Here, we studied the effect of Anamu-SC and P2Et extracts in the human adipose-derived MSC (hAMSC)-tumor cell interaction as a TME model. We also investigated the influence of the hAMSC secretome, in combination with these natural products, on tumor cell hallmarks such as viability, clonogenicity, and migration. In addition, hAMSC gene expression and protein synthesis were evaluated for some key factors in tumor progression in the presence of the extracts by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Multiplex, respectively. It was found that the presence of the hAMSC secretome did not affect the cytotoxic or clonogenicity-reducing activities of the natural extracts on cancer cells, and even this secretome can inhibit the migration of these tumor cells, in addition to the fact that the profile of molecules can be modified by natural products. Overall, our findings demonstrate that hAMSC secretome participation in TME interactions can favor the antitumor activities of natural products.

Sustained release of stem cell secretome from nano-villi chitosan microspheres for effective treatment of atopic dermatitis

Canine atopic dermatitis (AD) arises from hypersensitive immune reactions. AD symptoms entail severe pruritus and skin inflammation, with frequent relapses. Consequently, AD patients require continuous management, imposing financial burdens and mental fatigue on pet owners. In this study, we aimed to investigate the therapeutic relevance of secretome from canine adipose tissue-derived mesenchymal stem cells (MSCs), especially after encapsulation in nano-villi chitosan microspheres (CS-MS) to expect improved efficacy. Conditioned media (CM) from MSCs significantly inhibited the proliferation of splenocytes, induced the generation of regulatory T cells, and decreased mast cell degranulation. We found that beneficial soluble factors known to reduce AD symptoms, including transforming growth factor-beta 1, were detectable after sequential concentration and lyophilization of CM. The CS-MS, developed by a phase inversion regeneration method, showed high loading and sustained release of the secretome. Local injection of secretome-loaded CS-MS (ST/SC-MS) effectively reduced clinical severity compared to groups treated with secretome. Histological analysis revealed that ST/SC-MS potently suppressed epidermal hyperplasia, immunocyte infiltration and mast cell activation in the lesion. Taken together, this study presents a novel therapeutic approach exhibiting more potent and prolonged immunoregulatory efficacy of MSC secretome for canine AD treatment.

Dissection of paracrine/autocrine interplay in lung tumor microenvironment mimicking cancer cell-monocyte co-culture models reveals proteins that promote inflammation and metastasis

BACKGROUND

Tumor cell-monocyte interactions play crucial roles in shaping up the pro-tumorigenic phenotype and functional output of tumor-associated macrophages. Within the tumor microenvironment, such heterotypic cell-cell interactions are known to occur via secretory proteins. Secretory proteins establish a diabolic liaison between tumor cells and monocytes, leading to their recruitment, subsequent polarization and consequent tumor progression.

METHODS

We co-cultured model lung adenocarcinoma cell line A549 with model monocytes, THP-1 to delineate the interactions between them. The levels of prototypical pro-inflammatory cytokines like TNF-𝛼, IL-6 and anti-inflammatory cytokines like IL-10 were measured by ELISA. Migration, invasion and attachment independence of lung cancer cells was assessed by wound healing, transwell invasion and colony formation assays respectively. The status of EMT was evaluated by immunofluorescence. Identification of secretory proteins differentially expressed in monocultures and co-culture was carried out using SILAC LC-MS/MS. Various insilico tools like Cytoscape, Reacfoam, CHAT and Kaplan-Meier plotter were utilized for association studies, pathway analysis, functional classification, cancer hallmark relevance and predicting the prognostic potential of the candidate secretory proteins respectively.

RESULTS

Co-culture of A549 and THP-1 cells in 1:10 ratio showed early release of prototypical pro-inflammatory cytokines TNF-𝛼 and IL-6, however anti-inflammatory cytokine, IL-10 was observed to be released at the highest time point. The conditioned medium obtained from this co-culture ratio promoted the migration, invasion and colony formation as well as the EMT of A549 cells. Co-culturing of A549 with THP-1 cells modulated the secretion of proteins involved in cell proliferation, migration, invasion, EMT, inflammation, angiogenesis and inhibition of apoptosis. Among these proteins Versican, Tetranectin, IGFBP2, TUBB4B, C2 and IFI30 were found to correlate with the inflammatory and pro-metastatic milieu observed in our experimental setup. Furthermore, dysregulated expression of these proteins was found to be associated with poor prognosis and negative disease outcomes in lung adenocarcinoma compared to other cancer types. Pharmacological interventions targeting these proteins may serve as useful therapeutic approaches in lung adenocarcinoma.

CONCLUSION

In this study, we have demonstrated that the lung cancer cell-monocyte cross-talk modulates the secretion of IFI30, RNH1, CLEC3B, VCAN, IGFBP2, C2 and TUBB4B favoring tumor growth and metastasis.

A systematic review of mesenchymal stem cell secretome: Functional annotations, gene clusters and proteomics analyses for bone formation

The regenerative capacity of mesenchymal stem cells (MSCs) is now attributed to their ability to release paracrine factors into the extracellular matrix that boost tissue regeneration, reduce inflammation and encourage healing. Understanding the MSC secretome is crucial for shifting the prototypic conventional cell-based therapies to cell-free regenerative treatments. This systematic review aimed to analyse the functional annotations of the secretome of human adult adipose tissue and bone marrow MSCs and unveil the gene clusters responsible for bone formation. Bioinformatics tools were used to identify the biological processes, molecular functions, hallmarks and KEGG pathways of adipose and bone marrow MSC secretome proteins. We found a substantial overlap in the functional annotations and protein compositions of both adipose and bone marrow MSC secretome indicating that MSC source may be noninfluencial with regards to tissue regeneration. Additionally, a novel network pharmacology-based analysis of the secreted proteins revealed that the commonly secreted proteins within a single source interact with multiple drugable targets of bone diseases and regulate various KEGG pathway. This study unravels the secretome profile of human adult adipose and bone marrow MSCs based on the current literature and provides valuable insights into the therapeutic use of the MSC secretome for cell-free therapies.

Transforming growth factor β1-enriched secretome up-regulate osteogenic differentiation of dental pulp stem cells, and a potential therapeutic for gingival wound healing: A comparative proteomics study

OBJECTIVES

Current study aimed at comparing the human dental pulp-derived stem cell (hDPSC) secretome (Control secretome) and transforming growth factor beta1 (TGF-β1)-transfected hDPSC secretome (TGF-β1 Secretome), which have the potential to be therapeutic in terms of regenerative dentistry, in terms of osteogenesis, adipogenesis and gingival wound healing with proteomic analyses.

MATERIALS AND METHODS

pCMV-TGF-β1 plasmid was transfected into hDPSCs by electroporation. hDPSC and TGF-β1 transfected hDPSC secretomes were collected for LC-MS/MS. Protein contents in control secretome and TGF-β1 secretome were analyzed by tandem mass spectrometry-based shotgun proteomic method. Bioinformatic evaluations for canonical pathways, upstream regulators and networks were completed via Ingenuity Pathway Analysis (IPA, QIAGEN) software. Surface marker expressions between groups, treated secretome were measured by flow cytometry. To support the proteomic data morphologically, we performed osteogenic-adipogenic differentiation in hDPSCs treated with control secretome and TGF-β1 secretome, and scratch wound healing assay in gingival fibroblasts. Statistical analyses were performed by GraphPad Prism 8.02.

RESULTS

Venn diagram classification showed us 174 common proteins were identified from each group. In the control secretome 140 unique proteins were identified and 66 entries were exclusive for TGF-β1 secretome. TGF-β1 secretome was found to have therapeutic effect on MSC-specific immunophenotypes. TGF-β1 secretome was determined to up-regulate osteogenesis-related molecules and pathways while down-regulating adipogenesis-related pathways. Analysis of canonical pathways showed that TGF-β1 secretome is associated with the wound healing pathway.

CONCLUSION

Our study provided the first evidence that proteins identified in TGF-β1-transfected hDPSC secretomes are potential regulators of osteogenic/adipogenic differentiation and fibroblast wound healing.

CLINICAL SIGNIFICANCE

Based on these results, TGF-β1 secretome may have a therapeutic effect in repairing osteoporosis-related bone injuries, wound healing of oral mucosa and gingival tissue. TGF-β1 secretome may be a potential cell-free therapeutic in orthopedics and regenerative dentistry.

New era of mesenchymal stem cell-based medicine: basis, challenges and prospects

Stem cells of mesenchymal origin (MSC) arouse special interest due to their regenerative, anti-inflammatory, anti-apoptotic, anti-oxidative stress, antitumor or antimicrobial properties. However, its implementation in the clinic runs into drawbacks of cell therapy (immunological incompatibility, tumor formation, possible transmission of infections, entry into cellular senescence, difficult evaluation of safety, dose and potency; complex storage conditions, high economic cost or impractical clinical use). Considering that the positive effects of MSC are due, to a large extent, to the paracrine effects mediated by the set of substances they secrete (growth factors, cytokines, chemokines or microvesicles), the in vitro obtaining of these biological products makes possible a medicine cell-free regenerative therapy without the drawbacks of cell therapy. However, this new therapeutic innovation implies challenges, such as the recognition of the biological heterogeneity of MSC and the optimization and standardization of their secretome.

The epidermal integrin-mediated secretome regulates the skin microenvironment during tumorigenesis and repair

Integrins are cellular transmembrane receptors that physically connect the cytoskeleton with the extracellular matrix. As such, they are positioned to mediate cellular responses to microenvironmental cues. Importantly, integrins also regulate their own microenvironment through secreted factors, also known as the integrin-mediated secretome. Epidermal integrins, or integrins expressed by keratinocytes of the skin epidermis, regulate the cutaneous microenvironment through the contribution of matrix components, via proteolytic matrix remodeling, or by mediating factors like cytokines and growth factors that can promote support for nearby but distinct cells of the stroma, such as immune cells, endothelial cells, and fibroblasts. This role for integrins is enhanced during both pathological and repair tissue remodeling processes, such as tumor growth and progression and wound healing. This review will discuss examples of how the epithelial integrin-mediated secretome can regulate the tissue microenvironment. Although different epithelial integrins in various contexts will be explored, emphasis will be given to epidermal integrins that regulate the secretome during wound healing and cutaneous tumor progression. Epidermal integrin α3β1 is of particular focus as well, since this integrin has been revealed as a key regulator of the keratinocyte secretome.

Proteomic analysis of hypoxia and non-hypoxia secretome mesenchymal stem-like cells from human breastmilk

Introduction

Breastmilk contains proteins and cells which have stem cell properties. The human breastmilk stem cell mimick mesenchymal stem cells and expresses pluripotency genes. The protein level of breastmilk is high in colostrum and gradually subsides in the first year of lactation. The mesenchymal stem cells from breastmilk can be an alternative source of stem cells that can potentially affect cardiovascular therapy. This study aimed to identify the proteomic analysis of secretome mesenchymal stem-like cells under hypoxia compared to non-hypoxia from human breastmilk stem cells.

Material and methods

The human breastmilk was collected from six healthy breastfeeding women and transported to the laboratory under aseptic conditions. The breastmilk cells were isolated then cultured. After 72 h, the human breastmilk stem cells reached confluence then cleaned up and isolated in serum-free media (spheroid) to allow serial passaging every 48 h. The acquisition stem cell was made with flow cytometry. The cells were divided into hBSC secretomes under hypoxia (A) and non-hypoxia (B) and analyzed for LC-MS to identify the peptide structure.

Results

The human breastmilk cells contained several mesenchymal stem-like cells in density 2.4 × 10⁶ cell/mL for hypoxia and 2 × 10⁶ cell/mL for non-hypoxia conditions. The human breastmilk stem cell surface markers derived from the third cell passage process were 93.77% for CD44, 98.69% for CD73, 88.45% for CD90, and 96.30% for CD105. The protein level of secretome mesenchymal stem -like cells under hypoxia was measured at 5.56 μg/mL and 4.28 μg/mL for non-hypoxia. The liquid chromatography-mass spectrometry analysis identified 130 and 59 peptides from hypoxia and non-hypoxia of the human breastmilk stem cell secretome sequentially. Some important proteomics structures were found in the hypoxic human breastmilk stem cell secretome, such as transforming growth factor-β, VE-cadherin, and caspase.

Conclusion

The human breastmilk cells contain mesenchymal stem-like cells and a high concentration of CD44, CD73, CD90, and CD105 as surface markers at third passage culture. The hypoxic hBSC secretome produces a higher protein level compare to non-hypoxia. The transforming growth factor -β was found in the hypoxic hBSC secretome as a modulator of VEGF-mediated angiogenesis.

Substrate topographies modulate the secretory activity of human bone marrow mesenchymal stem cells

BACKGROUND

Mesenchymal stem cells (MSCs) secrete a diversity of factors with broad therapeutic potential, yet current culture methods limit potency outcomes. In this study, we used topographical cues on polystyrene films to investigate their impact on the secretory profile and potency of bone marrow-derived MSCs (hBM-MSCs). hBM-MSCs from four donors were cultured on topographic substrates depicting defined roughness, curvature, grooves and various levels of wettability.

METHODS

The topographical PS-based array was developed using razor printing, polishing and plasma treatment methods. hBM-MSCs from four donors were purchased from RoosterBio and used in co-culture with peripheral blood mononuclear cells (PBMCs) from Cell Applications Inc. in an immunopotency assay to measure immunosuppressive capacity. Cells were cultured on low serum (2%) for 24-48 h prior to analysis. Image-based analysis was used for cell quantification and morphology assessment. Metabolic activity of BM-hMSCs was measured as the mitochondrial oxygen consumption rate using an extracellular flux analyzer. Conditioned media samples of BM-hMSCs were used to quantify secreted factors, and the data were analyzed using R statistics. Enriched bioprocesses were identify using the Gene Ontology tool enrichGO from the clusterprofiler. One-way and two-way ANOVAs were carried out to identify significant changes between the conditions. Results were deemed statistically significant for combined P < 0.05 for at least three independent experiments.

RESULTS

Cell viability was not significantly affected in the topographical substrates, and cell elongation was enhanced at least twofold in microgrooves and surfaces with a low contact angle. Increased cell elongation correlated with a metabolic shift from oxidative phosphorylation to a glycolytic state which is indicative of a high-energy state. Differential protein expression and gene ontology analyses identified bioprocesses enriched across donors associated with immune modulation and tissue regeneration. The growth of peripheral blood mononuclear cells (PBMCs) was suppressed in hBM-MSCs co-cultures, confirming enhanced immunosuppressive potency. YAP/TAZ levels were found to be reduced on these topographies confirming a mechanosensing effect on cells and suggesting a potential role in the immunomodulatory function of hMSCs.

CONCLUSIONS

This work demonstrates the potential of topographical cues as a culture strategy to improve the secretory capacity and enrich for an immunomodulatory phenotype in hBM-MSCs.

Culturing Conditions Dictate the Composition and Pathways Enrichment of Human and Rat Perirenal Adipose-Derived Stromal Cells' Secretomes

Understanding the impact of various culturing strategies on the secretome composition of adipose-derived stromal cells (ASC) enhances their therapeutic potential. This study investigated changes in the secretome of perirenal ASC (prASC) under different conditions: normoxia, cytokine exposure, high glucose, hypoxia, and hypoxia with high glucose. Using mass spectrometry and enrichment clustering analysis, we found that normoxia enriched pathways related to extracellular matrix (ECM) organization, platelet degranulation, and insulin-like growth factor (IGF) transport and uptake. Cytokine exposure influenced metabolism, vascular development, and protein processing pathways. High glucose affected the immune system, metabolic processes, and IGF transport and uptake. Hypoxia impacted immune and metabolic processes and protein processing. Combined hypoxia and high glucose influenced the immune system, IGF transport and uptake, and ECM organization. Our findings highlight the potential of manipulating culturing conditions to produce secretomes with distinct protein and functional profiles, tailoring therapeutic strategies accordingly.

Pyrene remediation by Trametes maxima: an insight into secretome response and degradation pathway

The rapid pace of economic development has resulted in the release of several polycyclic aromatic hydrocarbons (PAHs) into the environment. Microbial degradation using white-rot fungi is a promising method for the removal of PAHs from the environment. In the present study, biodegradation of recalcitrant PAH by a white-rot fungus, Trametes maxima IIPLC-32, was investigated using pyrene. The pyrene concentration decreased by 79.80%, 65.37%, and 56.37% within 16 days from the initial levels of 10 mg L^-1, 25 mg L^-1, and 50 mg L^-1, respectively. Gas chromatographic-mass spectrometric identification of prominent metabolites 1-hydroxypyrene, 2-methyl-1-naphthyl acetic acid, di-n-butyl phthalate, and diethyl phthalate helped in determining the pyrene degradation pathway. The presence of 81 extracellular proteins was revealed by secretome analysis. The identified proteins up-regulated in response to pyrene degradation were classified into detoxification proteins (6.12%), redox proteins (6.12%), stress proteins (4.08%), metabolic-related proteins (26.53%), translation and transcriptional proteins (49%), catalytic proteins (49%), and other proteins (8.16%). Knowledge of secretome analysis in pyrene degradation helped to understand the degradation mechanism of pyrene. Also, the study suggests that T. maxima IIPLC-32 has the potential to be used in the bioremediation of PAH contaminated aquatic environment.

The secretome as a biomarker and functional agent in heart failure

Heart failure (HF) is a complex and multifactorial disease. Recent advances have been made in understanding the underlying molecular processes involved in HF pathogenesis. These scientific advancements have brought to light the importance of the secretome. This paper presents a thorough overview of the state of science regarding the secretome's involvement in the onset, progression, and possibility of improved diagnosis and therapeutic interventions in HF. We explore the various types of secreted factors, including novel proteins, growth factors, cytokines, and microRNAs. We also discuss how they affect cellular signaling, angiogenesis, fibrosis, pathological cardiac remodeling, and inflammation in HF. Furthermore, we examine the role of the secretome in cardioprotection and cardiotoxicity. This review emphasizes the potential of the secretome for biomarker discovery. This might enable better HF diagnosis, risk stratification, monitoring and treatment. The review also discusses the difficulties on investigating the role of secreted factors and novel directions on secretome research. It highlights its potential as a target for novel therapeutic approaches and biomarker development.

Whole genome sequencing of Wilsonomyces carpophilus, an incitant of shot hole disease in stone fruits: insights into secreted proteins of a necrotrophic fungal repository

BACKGROUND

Shot hole is one of the important fungal diseases in stone fruits viz., peach, plum, apricot and cherry caused by Wilsonomyces carpophilus and almond among nut crops. Fungicides significantly decrease the disease. Pathogenicity studies proved a wide host range of the pathogen infecting all stone fruits and almond among the nut crops, however, the mechanism underlying host-pathogen interaction is still unknown. Molecular detection of the pathogen using polymerase chain reaction (PCR) based simple sequence repeat (SSR) markers is also unknown due to the unavailability of the pathogen genome.

METHODS AND RESULTS

We examined the morphology, pathology and genomics of the Wilsonomyces carpophilus. Whole genome sequencing of the W. carpophilus was carried out by Illumina HiSeq and PacBio high throughput sequencing plate-forms through hybrid assembly. Constant selection pressure alters the molecular mechanism of the pathogen causing disease. The studies revealed that the necrotrophs are more lethal with a complex pathogenicity mechanism and little-understood effector repositories. The different isolates of necrotrophic fungus W. carpophilus causing shot hole in stone fruits namely peach, plum, apricot and cherry, and almonds among the nut crops showed a significant variation in their morphology, however, the probability value (p = 0.29) suggests in-significant difference in the pathogenicity. Here, we reported draft genome of W. carpophilus of size 29.9 Mb (Accession number: PRJNA791904). A total of 10,901 protein-coding genes were predicted, including heterokaryon incompatibility genes, cytochrome-p450 genes, kinases, sugar transporters among others. We found 2851 simple sequence repeats (SSRs), tRNAs, rRNAs and pseudogenes in the genome. The most prominent proteins showing necrotrophic lifestyle of the pathogen were hydrolases, polysaccharide-degrading enzymes, esterolytic, lipolytic, and proteolytic enzymes accounted for 225 released proteins. Among the 223 fungal species, top-hit species distribution revealed the majority of hits against the Pyrenochaeta species followed by Ascochyta rabiei and Alternaria alternata.

CONCLUSION

Draft genome of W. carpophilus is 29.9 Mb based on Illumina HiSeq and PacBio hybrid assembly. The necrotrophs are more lethal with a complex pathogenicity mechanism. A significant variation in morphology was observed in different pathogen isolates. A total of 10,901 protein-coding genes were predicted in the pathogen genome including heterokaryon incompatibility, cytochrome-p450 genes, kinases and sugar transporters. We found 2851 SSRs, tRNAs, rRNAs and pseudogenes, and prominent proteins showing necrotrophic lifestyle such as hydrolases, polysaccharide-degrading enzymes, esterolytic, lipolytic and proteolytic enzymes. The top-hit species distribution were against the Pyrenochaeta spp. followed by Ascochyta rabiei.

Comparative secretome analysis between salinity-tolerant and control Chlamydomonas reinhardtii strains

Secretome analysis of a salt-tolerant and control Chlamydomonas reinhardtii revealed 514 differentially expressed proteins. Membrane transport and trafficking, signal transduction and channel proteins were up-regulated in the ST secretome. Salinity is a major abiotic stress that limits crop production worldwide. Multiple adverse effects have been reported in many living organisms exposed to high-saline concentrations. Chlamydomonas reinhardtii is known for secreting proteins in response to many environmental stresses. A salinity-tolerant (ST) strain of Chlamydomonas has been developed, whose cells were able to grow at 300 mM NaCl. The current study analyzed the secretomes of ST grown in TAP medium supplemented with 300 mM NaCl and the laboratory strain CC-503 grown in TAP medium without NaCl supplement. In total, 514 secreted proteins were identified of which 203 were up-regulated and 110 were down-regulated. Bioinformatic analysis predicted 168 proteins to be secreted or in the conventional secretory pathway. Out of these, 70 were up-regulated, while 51 proteins were down-regulated. Proteins involved in membrane transport and trafficking, signal transduction and channel proteins were altered in their expression in the ST secretome, suggesting the response of saline stress acts toward not only the intracellular pool of proteins but also the extracellular proteins. This also suggested that the secreted proteins might have roles in the extracellular space. Signal peptide (SP) prediction revealed that almost 40% of the predicted secreted proteins contained a signal peptide; however, a high proportion of proteins lacked an SP, suggesting that these proteins might be secreted through an unconventional protein secretion pathway.