Tissue Explant Cultures Research Articles

Enhancing Bioluminescence Imaging of Cultured Tissue Explants Using Optical Telecompression.

Long-term observation of single-cell oscillations within tissue networks is now possible by combining bioluminescence reporters with stable tissue explant culture techniques. This method is particularly effective in revealing the network dynamics in systems with slow oscillations, such as circadian clocks. However, the low intensity of luciferase-based bioluminescence requires signal amplification using specialized cameras (e.g., I-CCDs and EM-CCDs) and prolonged exposure times, increasing baseline noise and reducing temporal resolution. To address this limitation, we implemented a cost-effective optical enhancement technique called telecompression, first used in astrophotography and now commonly used in digital photography. By combining a high numerical aperture objective lens with a magnification-reducing relay lens, we significantly increased the collection efficiency of the bioluminescence signal without raising the baseline CCD noise. This method allows for shorter exposure times in time-lapse imaging, enhancing temporal resolution and enabling more precise period estimations. Our implementation demonstrates the feasibility of telecompression for enhancing bioluminescence imaging for the tissue-level network observation of circadian clocks.

Importance of Media Composition and Explant Type in Cannabis sativa Tissue Culture.

Producing uniform Cannabis sativa (Cannabis) for medicinal/recreational flower production through sexual propagation has been problematic, leading to dominance of clonal propagation from "mother plants" in the cannabinoid industry, which also faces significant limitations. Cannabis tissue culture (TC) methods have been developed to overcome these challenges, but the long-term health and maintenance of Cannabis explants in TC have been largely overlooked in previous studies. The current study focused on the development of an efficient and optimized micropropagation protocol covering the entire process, with a specific focus on the health and performance in the multiplication stage. Multiplication media were formulated hormone-free to avoid longer-term vitrification issues, resulting in single-main-shoot cultures rather than multiple-shoot cultures. This instigated the use of stage II explant types different from the standard shoot tips previously used for multiple shoot cultures. Multiplication media were further improved from the basal salt composition via nitrogen and calcium additives. The optimized protocol was used on eight diverse Cannabis cultivars to test its applicability across various genetic backgrounds. Results indicated that the protocol was effective for conservation purposes across all cultivars and achieved good long-term multiplication rates for some but not all. The outcomes of this study mark a significant stride towards an efficient Cannabis TC methodology ready for more comprehensive industrial applications.

3D Culture Analysis of Cancer Cell Adherence to Ex Vivo Lung Microexplants.

Ex vivo 3D culture of human tissue explants addresses many limitations of traditional monolayer cell culture techniques, namely the lack of cellular heterogeneity and absence of 3D intercellular spatial relationships, but presents challenges with regard to repeatability owing to the difficulty of acquiring multiple tissue samples from the same donor. In this study, we used a cryopreserved bank of human lung microexplants, ∼1 mm3 fragments of peripheral lung from donors undergoing lung resection surgery, and a liquid-like solid 3D culture matrix to describe a method for the analysis of non-small-cell lung cancer adhesion to human lung tissue. H226 (squamous cell carcinoma), H441 (lung adenocarcinoma), and H460 (large cell carcinoma) cell lines were cocultured with lung microexplants. Confocal fluorescence microscopy was used to visualize the adherence of each cell line to lung microexplants. Adherent cancer cells were quantified following filtration of nonadherent cells, digestion of cultured microexplants, and flow cytometry. This method was used to evaluate the role of integrins in cancer cell adherence. A statistically significant decrease in the adherence of H460 cells to lung microexplants was observed when anti-integrins were administered to H460 cells before coculture with lung microexplants.

Inhalable spray-dried porous microparticles containing dehydroandrographolide succinate phospholipid complex capable of improving and prolonging pulmonary anti-inflammatory efficacy in mice.

Due to the unique physiological barriers within the lungs, there are considerable challenges in developing drug delivery systems enabling prolonged drug exposure to respiratory epithelial cells. Here, we report a PulmoSphere-based dry powder technology that incorporates a drug-phospholipid complex to promote intracellular retention of dehydroandrographolide succinate (DAS) in respiratory epithelial cells following pulmonary delivery. The DAS-phospholipid complex has the ability to self-assemble into nanoparticles. After spray-drying to produce PulmoSphere microparticles loaded with the drug-phospholipid complex, the rehydrated microparticles discharge the phospholipid complex without altering its physicochemical properties. The microparticles containing the DAS-phospholipid complex exhibit remarkable aerodynamic properties with a fine particle fraction of ∼ 60% and a mass median aerodynamic diameter of ∼ 2.3μm. These properties facilitate deposition in the alveolar region. In vitro cell culture and lung tissue explants experiments reveal that the drug-phospholipid complex prolongs intracellular residence time and lung tissue retention due to the slow intracellular disassociation of drug from the complex. Once deposited in the lungs, the DAS-phospholipid complex loaded microparticles increase and extend drug exposure to the lung tissues and the immune cells compared to the free DAS counterpart. The improved drug exposure to airway epithelial cells, but not immune cells, is related to a prolonged duration of pulmonary anti-inflammation at decreased doses in a mouse model of acute lung injury induced by lipopolysaccharide. Overall, the phospholipid complex loaded microparticles present a promising approach for improved treatment of respiratory diseases, e.g. pneumonia and acute respiratory distress syndrome.

GWAS determined genetic loci associated with callus induction in oil palm tissue culture.

GWAS identified six loci at 25kb downstream of WAK2, a crucial gene for cell wall and callus formation, enabling development of a SNP marker for enhanced callus induction potential. Efficient callus induction is vital for successful oil palm tissue culture, yet identifying genomic loci and markers for early detection of genotypes with high potential of callus induction remains unclear. In this study, immature male inflorescences from 198 oil palm accessions (dura, tenera and pisifera) were used as explants for tissue culture. Callus induction rates were collected at one-, two- and three-months after inoculation (C1, C2 and C3) as phenotypes. Resequencing generated 11,475,258 high quality single nucleotide polymorphisms (SNPs) as genotypes. GWAS was then performed, and correlation analysis revealed a positive association of C1 with both C2 (R = 0.81) and C3 (R = 0.50), indicating that C1 could be used as the major phenotype for callus induction rate. Therefore, only significant SNPs (P ≤ 0.05) in C1 were identified to develop markers for screening individuals with high potential of callus induction. Among 21 significant SNPs in C1, LD block analysis revealed six SNPs on chromosome 12 (Chr12) potentially linked to callus formation. Subsequently, 13 SNP markers were identified from these loci and electrophoresis results showed that marker C-12 at locus Chr12_12704856 can be used effectively to distinguish the GG allele, which showed the highest probability (69%) of callus induction. Furthermore, a rapid SNP variant detection method without electrophoresis was established via qPCR-based melting curve analysis. Our findings facilitated marker-assisted selection for specific palms with high potential of callus induction using immature male inflorescence as explant, aiding ortet palm selection in oil palm tissue culture.

Chitosan-Polyethylene Glycol Inspired Polyelectrolyte Complex Hydrogel Templates Favoring NEO-Tissue Formation for Cardiac Tissue Engineering.

Neo-tissue formation and host tissue regeneration determine the success of cardiac tissue engineering where functional hydrogel scaffolds act as cardiac (extracellular matrix) ECM mimic. Translationally, the hydrogel templates promoting neo-cardiac tissue formation are currently limited; however, they are highly demanding in cardiac tissue engineering. The current study focused on the development of a panel of four chitosan-based polyelectrolyte hydrogels as cardiac scaffolds facilitating neo-cardiac tissue formation to promote cardiac regeneration. Chitosan-PEG (CP), gelatin-chitosan-PEG (GCP), hyaluronic acid-chitosan-PEG (HACP), and combined CP (CoCP) polyelectrolyte hydrogels were engineered by solvent casting and assessed for physiochemical, thermal, electrical, biodegradable, mechanical, and biological properties. The CP, GCP, HACP, and CoCP hydrogels exhibited excellent porosity (4.24 ± 0.18, 13.089 ± 1.13, 12.53 ± 1.30 and 15.88 ± 1.10 for CP, GCP, HACP and CoCP, respectively), water profile, mechanical strength, and amphiphilicity suitable for cardiac tissue engineering. The hydrogels were hemocompatible as evident from the negligible hemolysis and RBC aggregation and increased adsorption of plasma albumin. The hydrogels were cytocompatible as evident from the increased viability by MTT (>94% for all the four hydrogels) assay and direct contact assay. Also, the hydrogels supported the adhesion, growth, spreading, and proliferation of H9c2 cells as unveiled by rhodamine staining. The hydrogels promoted neo-tissue formation that was proven using rat and swine myocardial tissue explant culture. Compared to GCP and CoCP, CP and HACP were superior owing to the cell viability, hemocompatibility, and conductance, resulting in the highest degree of cytoskeletal organization and neo-tissue formation. The physiochemical and biological performance of these hydrogels supported neo-cardiac tissue formation. Overall, the CP, GCP, HACP, and CoCP hydrogel systems promise novel translational opportunities in regenerative cardiology.

Injectable hydrogel induces regeneration of naturally degenerate human intervertebral discs in a loaded organ culture model

Low back pain resulting from disc degeneration is a leading cause of disability worldwide. However, to date few therapies target the cause and fail to repair the intervertebral disc (IVD). This study investigates the ability of an injectable hydrogel (NPgel), to inhibit catabolic protein expression and promote matrix expression in human nucleus pulposus (NP) cells within a tissue explant culture model isolated from degenerate discs. Furthermore, the injection capacity of NPgel into naturally degenerate whole human discs, effects on mechanical function, and resistance to extrusion during loading were investigated. Finally, the induction of potential regenerative effects in a physiologically loaded human organ culture system was investigated following injection of NPgel with or without bone marrow progenitor cells. Injection of NPgel into naturally degenerate human IVDs increased disc height and Young's modulus, and was retained during extrusion testing. Injection into cadaveric discs followed by culture under physiological loading increased MRI signal intensity, restored natural biomechanical properties and showed evidence of increased anabolism and decreased catabolism with tissue integration observed. These results provide essential proof of concept data supporting the use of NPgel as an injectable therapy for disc regeneration. Statement of significanceLow back pain resulting from disc degeneration is a leading cause of disability worldwide. However, to date few therapies target the cause and fail to repair the intervertebral disc. This study investigated the potential regenerative properties of an injectable hydrogel system (NPgel) within human tissue samples. To mimic the human in vivo conditions and the unique IVD niche, a dynamically loaded intact human disc culture system was utilised. NPgel improved the biomechanical properties, increased MRI intensity and decreased degree of degeneration. Furthermore, NPgel induced matrix production and decreased catabolic factors by the native cells of the disc. This manuscript provides evidence for the potential use of NPgel as a regenerative biomaterial for intervertebral disc degeneration.

Establishing surface sterilization protocol for clonal apple rootstock MM106

Surface sterilization is crucial in preparing viable and uncontaminated explants for tissue culture. Utilizing the right sterilizing agent in this procedure can efficiently eliminate the majority of surface contaminants. The present study aimed to establish the best sterilization procedure for clonal apple rootstock MM106 using shoot tips and nodal segments. Two important sterilizing agents, mercuric chloride (ranging from 0.05% to 0.3%) for various durations (2 to 6 minutes) and sodium hypochlorite (ranging from 3.0% to 12%) for different durations (10 to 30 minutes), were employed. The results indicated that the maximum aseptic conditions (80.00% and 80.67%) and survival rates of the cultures (60.66% and 67.33%) for shoot tips and nodal segments, respectively, were achieved through surface sterilization with 0.1% mercuric chloride for 4 minutes, specifically during April, in comparison to March and May of 2021 due to low phenol content and high meristematic activity. The results yielded valuable insights for efficiently propagating clonal apple rootstocks on a local scale, and they have the potential to offer guidance for establishing commercial facilities dedicated to producing these specific clonal apple rootstocks and varieties.

First report of yeast spot caused by Eremothecium coryli on soybean in South Korea

An ascomycete yeast was isolated from tissue cultures of soybean explants (cv. Williams 82) exhibiting blanching and discoloration. Stink bug damage was confirmed in soybean seeds that were grown and harvested simultaneously in the same field as the soybeans used for tissue culture, and the same yeast was isolated from areas of stink bug damage, indicating seed contamination. The seed infection rate was 20%, and all infected seeds had been damaged by stink bugs. The yeast was identified as Eremothecium coryli (Peglion) Kurtzman based on morphological and biochemical characteristics and homology analysis of the internal transcribed spacer sequence of the ribosomal RNA gene and the large ribosomal subunit D1/D2 domain regions. Disease symptoms were reproduced by inoculating this yeast into healthy soybeans (cv. Williams 82). Eremothecium coryli has been reported to cause yeast spot disease in soybeans, but has not been reported in Korea. Among the fungicides recommended for plant tissue culture, we recommend imazalil for addressing E. coryli contamination. The results of this study suggest that yeast spot caused by E. coryli presents a significant risk to soybean production.

Mechanical loading and hyperosmolarity as a daily resetting cue for skeletal circadian clocks

Daily rhythms in mammalian behaviour and physiology are generated by a multi-oscillator circadian system entrained through environmental cues (e.g. light and feeding). The presence of tissue niche-dependent physiological time cues has been proposed, allowing tissues the ability of circadian phase adjustment based on local signals. However, to date, such stimuli have remained elusive. Here we show that daily patterns of mechanical loading and associated osmotic challenge within physiological ranges reset circadian clock phase and amplitude in cartilage and intervertebral disc tissues in vivo and in tissue explant cultures. Hyperosmolarity (but not hypo-osmolarity) resets clocks in young and ageing skeletal tissues and induce genome-wide expression of rhythmic genes in cells. Mechanistically, RNAseq and biochemical analysis revealed the PLD2-mTORC2-AKT-GSK3β axis as a convergent pathway for both in vivo loading and hyperosmolarity-induced clock changes. These results reveal diurnal patterns of mechanical loading and consequent daily oscillations in osmolarity as a bona fide tissue niche-specific time cue to maintain skeletal circadian rhythms in sync.

Evaluation of the therapeutic effects of oestradiol on the systemic inflammatory response and on lung injury caused by the occlusion of the proximal descending aorta in male rats.

Ischaemia and reperfusion-induced microvascular dysfunction is a serious problem encountered during a variety surgical procedures, leading to systemic inflammation and affecting remote organs, specially the lungs. 17β-Oestradiol reduces pulmonary repercussions from various acute lung injury forms. Here, we focused on the 17β-oestradiol therapeutic effects after aortic ischaemia and reperfusion (I/R) by evaluating lung inflammation. Twenty-four Wistar rats were submitted to I/R by insufflation of a 2-F catheter in thoracic aorta for 20 min. Reperfusion took 4 h and 17β-oestradiol (280 µg/kg, i.v.) was administered after 1 h of reperfusion. Sham-operated rats were controls. Bronchoalveolar lavage was performed and lung samples were prepared for histopathological analysis and tissue culture (explant). Interleukin (IL)-1β, IL-10 and tumour necrosis factor-α were quantified. After I/R, higher number of leukocytes in bronchoalveolar lavage were reduced by 17β-oestradiol. The treatment also decreased leukocytes in lung tissue. I/R increased lung myeloperoxidase expression, with reduction by 17β-oestradiol. Serum cytokine-induced neutrophil chemoattractant 1 and IL-1β increased after I/R and 17β-oestradiol decreased cytokine-induced neutrophil chemoattractant 1. I/R increased IL-1β and IL-10 in lung explants, reduced by 17β-oestradiol. Our results showed that 17β-oestradiol treatment performed in the period of reperfusion, modulated the systemic response and the lung repercussions of I/R by thoracic aortic occlusion. Thus, we can suggest that 17β-oestradiol might be a supplementary approach leading the lung deterioration after aortic clamping in surgical procedures.

Efficacy of Neem Seed Extract in the Control of Fusarium Oxysporum of Ginger (Zingiber Officinale) Explants in Tissue Culture and Micropropagation

In spite the most stringent use of sterile technique during plants micro propagation, the nutrient in which the plants tissue is cultivated, is a good source of medium for microbial growth. These microbes compete adversely with the tissue culture material for nutrients. The contaminated plants culture remains a persistent problem that results to losses ranging from small number of cultures to the catastrophic lost of the whole batches of culture media and tissue cultures. The study shows the number of ginger explants initiated revealed that 62.5% were contaminated with Fusarium oxysporum which signified that these isolates constitute the major contaminants in the micropropagation of ginger which originated from the field or green house, 16.7% were contaminated with other organisms, while 20.8% uncontaminated culture tubes. The neem seed extract of water and ethanol extract at concentration of 0.5, 1.0, 1.5, 2.0 and 2.5mg/ml were compared against Benlate; a commercially available fungicide for their antifungal activities against mycelium growth of Fusarium oxysporum. The results shows that the concentrations at 2.5mg/ ml of both Benlate and ethanol neem seeds extracts were highly effective in inhibiting the mycelium growth of F. oxysporum of 56.0mm and 55.6mm respectively. This is significantly (P<0.05) higher than the water neem seed extracts across the concentration levels. The concentrations at 2.0mg/ml of Benlate and ethanol neem seeds extracts were significantly effective for inhibiting F. oxysporum than their corresponding water extracts with the highest inhibition of 28.0mm at 2.5mg/ml. The result thus, indicates ethanol neem seeds extracts at 2.5mg/ml could be used to inhibit mycelium growth of Fusarium oxysporum to substitute Benlate. The use of antibiotics to control latent bacterial contamination in tissue culture techniques has disadvantage, they are usually heat-labile and often phototoxic and only effective against bacteria not fungi. The addition of antibiotics to tissue culture medium causes reduction in vigour, chlorosis in propagated plantlets and capable of altering the behavior of culture medium. Therefore, the use of ethanol neem seed extracts also has an added advantage of been an organic material in the medium and effective with the occurring benefit of non toxicity to the growth of in- vitro cultures.

1499-P: Adipocyte Development from Mesenchymal Progenitor Cells Differ between Subjects with Normal Glucose Tolerance or Type 2 Diabetes

Subcutaneous adipose tissue protects from T2D by sequestering lipids and preventing lipotoxicity and insulin resistance. Adipose depots are maintained throughout the lifetime by the formation of new adipocytes from mesenchymal progenitor cells that reside within the tissue. In previous studies, we have found that mesenchymal progenitor cells from human adipose tissue can be expanded with little loss of multipotency by culturing tissue explants in 3-dimensional hydrogels under pro-angiogenic conditions. Mesenchymal progenitor cells obtained in this manner can be induced to differentiate into multiple adipocyte subtypes, including beige adipocytes characterized by their induction of UCP1 upon cAMP elevation. Using this approach, we explored whether mesenchymal progenitor cells from the subcutaneous abdominal (ABD) and gluteal (GLU) depots of subjects with normal glucose tolerance (NGT) or T2D would differ in their capacity to differentiate into adipocyte subtypes. Results from n=12 subjects (6 with NGT and 6 with T2D) revealed no significant differences between depots or glycemic states in the number of mesenchymal progenitor cells that can be expanded, in their proliferative rate upon subsequent passaging, or in their capacity to differentiate into either white or beige adipocytes. However, we found that cells from either the ABD or GLUT depot from NGT subjects displayed substantial spontaneous adipocyte differentiation even without adipogenic induction, but cells from subjects with T2D did not. This difference was highly significant, and potentially reflects a diminished capacity of mesenchymal progenitor cells to maintain subcutaneous adipose depots in-vivo in subjects with T2D. Further transcriptomic and epigenomic analyses of expanded progenitor cells, currently underway, has the potential to reveal cellular mechanisms of impaired spontaneous adipocyte differentiation in subjects with Type 2 Diabetes. Disclosure S.Corvera: None. T.A.Desouza: None. R.N.Ziegler: None. N.Rosano: None. M.J.Thompson: None.

Autophagy regulates sex steroid hormone synthesis through lysosomal degradation of lipid droplets in human ovary and testis

Autophagy is an evolutionarily conserved process that aims to maintain the energy homeostasis of the cell by recycling long-lived proteins and organelles. Previous studies documented the role of autophagy in sex steroid hormone biosynthesis in different animal models and human testis. Here we demonstrate in this study that sex steroid hormones estrogen and progesterone are produced through the same autophagy-mediated mechanism in the human ovary in addition to the human testis. In brief, pharmacological inhibition and genetic interruption of autophagy through silencing of autophagy genes (Beclin1 and ATG5) via siRNA and shRNA technologies significantly reduced basal and gonadotropin-stimulated estradiol (E2), progesterone (P4) and testosterone (T) production in the ex vivo explant tissue culture of ovary and testis and primary and immortalized granulosa cells. Consistent with the findings of the previous works, we observed that lipophagy, a special form of autophagy, mediates the association of the lipid droplets (LD)s with lysosome to deliver the lipid cargo within the LDs to lysosomes for degradation in order to release free cholesterol required for steroid synthesis. Gonadotropin hormones are likely to augment the production of sex steroid hormones by upregulating the expression of autophagy genes, accelerating autophagic flux and promoting the association of LDs with autophagosome and lysosome. Moreover, we detected some aberrations at different steps of lipophagy-mediated P4 production in the luteinized GCs of women with defective ovarian luteal function. The progression of autophagy and the fusion of the LDs with lysosome are markedly defective, along with reduced P4 production in these patients. Our data, together with the findings of the previous works, may have significant clinical implications by opening a new avenue in understanding and treatment of a wide range of diseases, from reproductive disorders to sex steroid-producing neoplasms, sex steroid-dependent malignancies (breast, endometrium, prostate) and benign disorders (endometriosis).

Evaluating the effect of gamma rays on Zamiifolia (Zamioculcas zamiifolia) plant in vitro and genetic diversity of the resulting genotypes using the ISSR marker

Zamiifolia (Zamioculcas sp.) is a perennial plant in the Araceae family and one of the new apartment plants in the world. In this study, in order to increase the effectiveness of the breeding program, tissue culture technique and explants of leaf parts were used. The results indicated that 2,4-D (1 mg/l) and BA (2 mg/l) hormones affected positively and significantly callus formation and simultaneous application of NAA and BA (both in 0.5 mg/l) caused the best results regarding seedling production and number, leaves, complete tubers, and root in tissue culture of Zaamifolia. In the study, three cultivars of Zamiifolia (green, black and Dutch) and 12 genotypes resulted from callus formation stage, irradiated with different gamma rays (0 to 175 Gy, with LD50 as 68 Gy) were selected and the presence of genetic diversity was investigated using 22 ISSR primers. Applying ISSR marker showed that the highest amount of PIC values related to the F19(0.47) and F20(0.38) primers, which persuasively isolated the studied genotypes. Moreover, the highest efficiency was detected for AK66 marker based on the MI parameter. The PCA and clustering categorization via UPGMA methodology based on molecular information and Dice index, differentiated the genotypes into 6 groups. Genotypes 1(callus), 2(100 Gy) and 3(cultivar from Holland) created separated groups. The 4th group included 6(callus), 8(0 Gy), 9(75 Gy), 11(90 Gy), 12(100 Gy) and 13(120 Gy) genotypes appearing as the largest group. The 5th group included 7(160 Gy), 10(80 Gy), 14(140 Gy) and 15(Zanziber gem black) genotypes. The last group included 4(mather plant) and 5(callus) genotypes. In this context, genotypes 1, 5, and 6 had probably somaclonal variation. Moreover, genotypes that received doses of 100 and 120 Gy, had a medium diversity. There is a high possibility of introducing a cultivar with a low dose and high genetic diversity in the whole group. Genotype 7 in this classification, received the highest dose of 160 Gy. In this population, the Dutch variety, was used as a new variety. As a result, the ISSR marker could correctly group the genotypes. This is an interesting finding, and it could be hypothesized that the ISSR marker could correctly differentiate Zaamifolia genotypes and probably other ornamental plants under the effect of gamma rays mutagenesis in order to achieve novel variants.

A Novel Tissue Explant Culture Model For Testing of Candidate Treatments for Inflammation of the Uterus in Pigs.

Abstract Background: Endometritis is an inflammatory condition of the uterus leading to complications with reproductive organs, miscarriage and infertility. The first-line treatment of endometritis in pigs are antibiotics, which do not always resolve inflammation and contribute to antibiotic resistance. There is an urgent need for the development of alternative treatments for endometritis. Here we propose and validate the first porcine tissue explant model for uterine inflammation and test naturally derived compounds for their effectiveness as anti-inflammatory therapies in porcine endometrial tissue. Methods: Uterine endometrial explants were harvested from uteri of sows sent to slaughter. Tissue biopsies were collected at follicular and luteal phases of the oestrous cycle. Biopsies were washed and these tissue ‘explants’ were cultured. Explants were treated at 24 hr with oxytocin (to stimulate PGF 2αproduction) or LPS (to mimic infection and induce inflammation. Explants were retained for RT-PCR analysis. Supernatants were harvested and concentrations of markers were measured by ELISA and Luminex. Results: The data generated thus far show a dose dependent response of IL-6 secretion to LPS stimulation, which demonstrates the validity of our model. Inflammation can be stimulated in an in vitrosetting to mimic porcine endometritis and we present data to show the change in cytokine levels in response to treatment with naturally derived compounds. Conclusions: This data shows that inflammation can be stimulated in an in vitrosetting to mimic porcine endometritis This model is a tool for testing of novel compounds and their potential anti-inflammatory effects on the porcine endometrium. Supported by an Innovate UK Grant (Project Reference: 98015) (https://gtr.ukri.org/projects?ref=98015)

Induction of Axillary Bud Swelling of Hevea brasiliensis to Regenerate Plants through Somatic Embryogenesis and Analysis of Genetic Stability.

To overcome rubber tree (RT) tissue culture explant source limitations, the current study aimed to establish a new Hevea brasiliensis somatic embryogenesis (SE) system, laying the technical foundation for the establishment of an axillary-bud-based seedling regeneration system. In this study, in vitro plantlets of Hevea brasiliensis Chinese Academy of Tropical Agricultural Sciences 917 (CATAS 917) were used as the experimental materials. Firstly, the optimum conditions for axillary bud swelling were studied; then, the effects of phenology, the swelling time of axillary buds (ABs), and medium of embryogenic callus induction were studied. Plantlets were obtained through somatic embryogenesis. Flow cytometry, inter-simple sequence repeat (ISSR molecular marker) and chromosome karyotype analysis were used to study the genetic stability of regenerated plants along with budding seedlings (BSs) and secondary somatic embryo seedlings (SSESs) as the control. The results show that the rubber tree's phenology period was mature, and the axillary bud induction rate was the highest in the 2 mg/L 6-benzyladenine (6-BA) medium (up to 85.83%). Later, 3-day-old swelling axillary buds were used as explants for callogenesis and somatic embryogenesis. The callus induction rate was optimum in MH (Medium in Hevea) + 1.5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) + 1.5 mg/L 1-naphthalene acetic acid (NAA) + 1.5 mg/L Kinetin (KT) + 70 g/L sucrose (56.55%). The regenerated plants were obtained after the 175-day culture of explants through callus induction, embryogenic callus induction, somatic embryo development, and plant regeneration. Compared with the secondary somatic embryo seedling control, axillary bud regeneration plants (ABRPs) were normal diploid plants at the cellular and molecular level, with a variation rate of 7.74%.

Ex vivo intervertebral disc cultures: degeneration-induction methods and their implications for clinical translation

Because low back pain is frequently a result of intervertebral disc degeneration (IVDD), strategies to regenerate or repair the IVD are currently being investigated. Often, ex vivo disc cultures of non-human IVD organs or tissue explants are used that usually do not exhibit natural IVDD. Therefore, degenerative changes mimicking those reported in human IVDD need to be induced. To support researchers in selecting ex vivo disc cultures, a systematic search was performed for them and their potential use for studying human IVDD reviewed. Five degeneration induction categories (proinflammatory cytokines, injury/damage, degenerative loading, enzyme, and other) were identified in 129 studies across 7 species. Methods to induce degeneration are diverse and can induce mild to severe degenerative changes that progress over time, as described for human IVDD. The induced degenerative changes are model-specific and there is no "one-fits-all" IVDD induction method. Nevertheless, specific aspects of human IVDD can be well mimicked. Currently, spontaneously degenerated disc cultures from large animals capture human IVDD in most aspects. Combinatorial approaches of several induction methods using discs derived from large animals are promising to recapitulate pathological changes on several levels, such as cellular behaviour, extracellular matrix composition, and biomechanical function, and therefore better mimic human IVDD. Future disc culture setups might increase in complexity, and mimic human IVDD even better. As ex vivo disc cultures have the potential to reduce and even replace animal trials, especially during preclinical development, advancement of such models is highly relevant for more efficient and cost-effective clinical translation from bench-to-bedside.

Proteomic Analysis of Mucosal and Systemic Responses to SARS-CoV-2 Antigen.

The mucosal environment of the upper respiratory tract is the first barrier of protection against SARS-CoV-2 transmission. However, the mucosal factors involved in viral transmission and potentially modulating the capacity to prevent such transmission have not fully been identified. In this pilot proteomics study, we compared mucosal and systemic compartments in a South African cohort of vaccinated and unvaccinated individuals undergoing maxillofacial surgery with previous history of COVID-19 or not. Inflammatory profiles were analyzed in plasma, nasopharyngeal swabs, and nasal and oral tissue explant cultures, using Olink and Luminex technologies. SARS-CoV-2-specific antibody levels were measured in serum and tissue explants. An increased pro-inflammatory proteomic profile was measured in the nasal compartment compared to plasma. However, IP-10 and MIG levels were higher in secretions than in nasal tissue, and the opposite was observed for TGF-β. Nasal anti-SARS-CoV-2 spike IgG correlated with mucosal MIG expression for all participants. A further positive correlation was found with IP-10 in BioNTech/Pfizer-vaccinated individuals. Systemic levels of anti-SARS-CoV-2 spike IgG elicited by this vaccine correlated with plasma IL-10, IL-6 and HBD4. Proteomic profiles measured in mucosal tissues and secretions using combined technologies could reveal correlates of protection at the mucosal portals of viral entry.

Exploring the Potential of PEG-Heparin Hydrogels to Support Long-Term Ex Vivo Culture of Patient-Derived Breast Explant Tissues.

Breast cancer is a complex, highly heterogenous, and dynamic disease and the leading cause of cancer-related death in women worldwide. Evaluation of the heterogeneity of breast cancer and its various subtypes is crucial to identify novel treatment strategies that can overcome the limitations of currently available options. Explant cultures of human mammary tissue have been known to provide important insights for the study of breast cancer structure and phenotype as they include the context of the surrounding microenvironment, allowing for the comprehensive exploration of patient heterogeneity. However, the major limitation of currently available techniques remains the short-term viability of the tissue owing to loss of structural integrity. Here, an ex vivo culture model using star-shaped poly(ethylene glycol) and maleimide-functionalized heparin (PEG-HM) hydrogels to provide structural support to the explant cultures is presented. The mechanical support allows the culture of the human mammary tissue for up to 3 weeks and prevent disintegration of the cellular structures including the epithelium and surrounding stromal tissue. Further, maintenance of epithelial phenotype and hormonal receptors is observed for up to 2 weeks of culture which makes them relevant for testing therapeutic interventions. Through this study, the importance of donor-to-donor variability and intra-patient tissue heterogeneity is reiterated.