Tethered TGF-β1 in a Hyaluronic Acid-Based Bioink for Bioprinting Cartilaginous Tissues

In 3D bioprinting for cartilage regeneration, bioinks that support chondrogenic development are of key importance. Growth factors covalently bound in non-printable hydrogels have been shown to effectively promote chondrogenesis. However, studies that investigate the functionality of tethered growth factors within 3D printable bioinks are still lacking. Therefore, in this study, we established a dual-stage crosslinked hyaluronic acid-based bioink that enabled covalent tethering of transforming growth factor-beta 1 (TGF‑β1). Bone marrow-derived mesenchymal stromal cells (MSCs) were cultured over three weeks in vitro, and chondrogenic differentiation of MSCs within bioink constructs with tethered TGF‑β1 was markedly enhanced, as compared to constructs with non-covalently incorporated TGF‑β1. This was substantiated with regard to early TGF‑β1 signaling, chondrogenic gene expression, qualitative and quantitative ECM deposition and distribution, and resulting construct stiffness. Furthermore, it was successfully demonstrated, in a comparative analysis of cast and printed bioinks, that covalently tethered TGF‑β1 maintained its functionality after 3D printing. Taken together, the presented ink composition enabled the generation of high-quality cartilaginous tissues without the need for continuous exogenous growth factor supply and, thus, bears great potential for future investigation towards cartilage regeneration. Furthermore, growth factor tethering within bioinks, potentially leading to superior tissue development, may also be explored for other biofabrication applications.

Effect of peripheral iridectomy on VEGF-A and TGF-β levels in rabbit aqueous humour

Background Peripheral iridectomy (PI), routinely performed during glaucoma filtration surgery, may contribute to scarring. This study aims to determine whether PI alters the concentrations of VEGF-A and TGF-β isoforms in the rabbit aqueous humour. Methods Anterior chamber paracentesis (ACP) was performed in both eyes of six New Zealand white rabbits, with additional surgical PI performed in the right eyes. Eyes were examined on postoperative days (PODs) 1, 7, 30 and 60 by means of the tonopen, slit-lamp biomicroscopy, and bead-based cytokine assays for TGF-β and VEGF-A concentrations in the aqueous humor. Results ACP caused a significant reduction in intraocular pressure (IOP) from mean preoperative 11.47 ± 1.01 mmHg to 5.67 ± 1.63 mmHg on POD 1 while PI did not cause further IOP reduction. Limbal conjunctival vasculature appeared slightly increased on POD 1 in both ACP and PI eyes with PI also causing mild bleeding from damaged iris vessels. Two PI eyes developed fibrinous anterior chamber reaction and/ or peripheral anterior synechiae. Aqueous VEGF-A levels were not significantly different between eyes treated with ACP and PI. Aqueous TGF-β concentrations distributed in the ratio of 4:800:1 for TGF-β1:TGF-β2:TGF-β3 respectively. While aqueous TGF-β2 was not significantly induced by either procedure at any time point, TGF-β1 and TGF-β3 were significantly induced above baseline levels by PI on POD 1. Conclusion PI increases the risk of inflammation. The combined induction of aqueous TGF-β1 and TGF-β3 by PI in glaucoma surgery may impact surgery success in glaucoma subtypes sensitive to these isoforms.

Comparative Metabolomics and Proteomics Reveal Vibrio parahaemolyticus Targets Hypoxia-Related Signaling Pathways of Takifugu obscurus

Coronavirus disease 2019 (COVID-19) raises the issue of how hypoxia destroys normal physiological function and host immunity against pathogens. However, there are few or no comprehensive omics studies on this effect. From an evolutionary perspective, animals living in complex and changeable marine environments might develop signaling pathways to address bacterial threats under hypoxia. In this study, the ancient genomic model animal Takifugu obscurus and widespread Vibrio parahaemolyticus were utilized to study the effect. T. obscurus was challenged by V. parahaemolyticus or (and) exposed to hypoxia. The effects of hypoxia and infection were identified, and a theoretical model of the host critical signaling pathway in response to hypoxia and infection was defined by methods of comparative metabolomics and proteomics on the entire liver. The changing trends of some differential metabolites and proteins under hypoxia, infection or double stressors were consistent. The model includes transforming growth factor-β1 (TGF-β1), hypoxia-inducible factor-1α (HIF-1α), and epidermal growth factor (EGF) signaling pathways, and the consistent changing trends indicated that the host liver tended toward cell proliferation. Hypoxia and infection caused tissue damage and fibrosis in the portal area of the liver, which may be related to TGF-β1 signal transduction. We propose that LRG (leucine-rich alpha-2-glycoprotein) is widely involved in the transition of the TGF-β1/Smad signaling pathway in response to hypoxia and pathogenic infection in vertebrates as a conserved molecule.

Protective effect of syringaresinol on rats with diabetic nephropathy via regulation of Nrf2/HO-1 and TGF- β1/Smads pathways

Purpose: To investigate the protective role of syringaresinol in a rat model of diabetic nephropathy (DN). Methods: Streptozotocin was injected intraperitoneally into rats to establish the diabetic model. Streptozotocin-induced rats were orally administered syringaresinol, and pathological changes in kidneys were assessed using hematoxylin and eosin staining. Enzyme-linked immunosorbent assay (ELISA) was used to determine kidney injury indicators, 24-h urine proteins, blood urea nitrogen (BUN), and serum creatinine (SCR). Blood glucose was measured using a blood glucose meter, while levels of malonaldehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX) in kidney were also measured using ELISA. Results: Pathological changes in the kidneys were observed in rats post-streptozotocin treatment. Administration of syringaresinol reduced the lesion degree, with improved pathological morphology in kidney. Syringaresinol administration significantly attenuated streptozotocin-increased levels of BUN, SCR, 24-h urine protein, and blood glucose (p < 0.01). Streptozotocin-induced oxidative stress, shown by enhanced MDA level and reduced levels of SOD, CAT, and GSH-PX, was reversed in rat kidneys following syringaresinol administration. However, the expression levels of nuclear factor erythropoietin- 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) proteins decreased, while transforming growth factor-beta 1 (TGF-β1) and signal transducer and transcriptional modulator (Smad) 2/3/7 proteins increased in rats post-streptozotocin treatment. Syringaresinol administration reversed the effects of streptozotocin on protein expression of Nrf2, HO-1, TGF-β1, and Smad 2/3/7. Conclusion: Syringaresinol exerted a protective effect against DN through activation of Nrf2 and inactivation of TGF-β1/Smad pathways. Thus, the compound can potentially be developed for management of diabetic nephropathy.

Recurrent Nephrotic Plasma Activates Pro-fibrotic Signalling Pathways Downstream of Protease-activated Receptor 1

Recurrence of steroid-resistant nephrotic syndrome (SRNS) is thought to be due to an unknown “circulating factor”, the identity of which has so far remained elusive. Our previous work suggests a signaling role for protease-activated receptor-1 (PAR-1), leading to impaired podocyte function. Here, we show that relapse nephrotic plasma (NP), but not paired remission plasma, induced a pro-fibrotic response. This change was inhibited by PAR-1 inhibitors, but not by TGF-β1 inhibition. Four PAR-1 inhibitors demonstrated distinct antagonistic properties. The phosphorylation of VASP and JNK in a 3D spheroid model (GlomSpheres) and kidney organoids corroborated the finding from a 2D ciPods model. Functionally, relapse NP induced podocyte motility, and podocyte loss from spheroids both of which were also selectively rescued by PAR-1 inhibitors. Also, it induced the loss of podocyte-specific markers in kidney organoids. We propose that the circulating factor acts as a pro-fibrotic effector by activating PAR-1, leading to increased podocyte injury.

Impact of the Plastein Reaction of Casein Hydrolysates in the Presence of Exogenous Amino Acids on Their Anti-Inflammatory Effect in the Lipopolysaccharide-Stimulated Macrophages

In this study, papain-generated casein hydrolysates (CH) with a degree of hydrolysis of 13.7% were subjected to a papain-mediated plastein reaction in the absence or presence of one of the exogenous amino acids—Gly, Pro, and Hyp—to prepare four plastein modifiers, or mixed with one of three amino acids to prepare three mixtures. The assay results confirmed that the reaction reduced free NH2 for the modifiers and caused amino acid incorporation and peptide condensation. When RAW264.7 macrophages were exposed to the CH, modifiers, and mixtures, these samples promoted macrophage growth and phagocytosis in a dose-dependent manner. In addition, the CH shared similar activity in the cells as the mixtures, while the modifiers (especially the PCH-Hyp prepared with Hyp addition) exerted higher potential than CH, the mixtures, and PCH (the modifier prepared without amino acid addition). The plastein reaction thus enhanced CH bioactivity in the cells. When RAW264.7 macrophages were stimulated with lipopolysaccharide (LPS), the inflammatory cells produced more lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) formation, and caused more four inflammatory mediators (NO, PGE2, TNF-α, and IL-6) and two anti-inflammatory mediators (TGF-β1 and IL-10). However, the PCH-Hyp, PCH, and CH at dose levels of 100 μg/mL could combat against the LPS-induced inflammation. Overall, the PCH-Hyp was more active than the CH and PCH in reducing LDH release, ROS formation, and the secretion of these inflammatory mediators, or in increasing the secretion of the anti-inflammatory mediators. The qPCR and Western blot analysis results further confirmed that these samples had anti-inflammatory effects on the stimulated cells by suppressing the LPS-induced activation of the NF-κB signaling pathway, via regulating the mRNA/miRNA expression of iNOS, IL-6, TNF-α, IL-1β, COX-2, TLR4, IL-10, TGF-β1, miR-181a, miR-30d, miR-155, and miR-148, as well as the protein expression of MyD88, p-IKKα, p-IκBα, p-NF-κB p65, and iNOS, involved in this signaling pathway. In addition, the immunofluorescence assay results revealed that these samples could block the LPS-mediated nuclear translocation of the p65 protein and displayed the same function as the NF-κB inhibitor BAY 11-7082. It was concluded that CH could be endowed with higher anti-inflammatory activity to the macrophages by performing a plastein reaction, particularly that in the presence of exogenous Hyp.