Engineering Pancreatic Islets to Transiently Codisplay on Their Surface Thrombomodulin and CD47 Immunomodulatory Proteins as a Means of Mitigating Instant Blood-Mediated Inflammatory Reaction following Intraportal Transplantation.

Most pancreatic islets are destroyed immediately after intraportal transplantation by an instant blood-mediated inflammatory reaction (IBMIR) generated through activation of coagulation, complement, and proinflammatory pathways. Thus, effective mitigation of IBMIR may be contingent on the combined use of agents targeting these pathways for modulation. CD47 and thrombomodulin (TM) are two molecules with distinct functions in regulating coagulation and proinflammatory responses. We previously reported that the islet surface can be modified with biotin for transient display of novel forms of these two molecules chimeric with streptavidin (SA), that is, thrombomodulin chimeric with SA (SA-TM) and CD47 chimeric with SA (SA-CD47), as single agents with improved engraftment following intraportal transplantation. This study aimed to test whether islets can be coengineered with SA-TM and SA-CD47 molecules as a combinatorial approach to improve engraftment by inhibiting IBMIR. Mouse islets were effectively coengineered with both molecules without a detectable negative impact on their viability and metabolic function. Coengineered islets were refractory to destruction by IBMIR ex vivo and showed enhanced engraftment and sustained function in a marginal mass syngeneic intraportal transplantation model. Improved engraftment correlated with a reduction in intragraft innate immune infiltrates, particularly neutrophils and M1 macrophages. Moreover, transcripts for various intragraft procoagulatory and proinflammatory agents, including tissue factor, HMGB1 (high-mobility group box-1), IL-1ß, IL-6, TNF-α, IFN-γ, and MIP-1α, were significantly reduced in coengineered islets. These data demonstrate that the transient codisplay of SA-TM and SA-CD47 proteins on the islet surface is a facile and effective platform to modulate procoagulatory and inflammatory responses with implications for both autologous and allogeneic islet transplantation.

Differential expression of programmed death 1 (PD-1) on various immune cells and its role in human leprosy.

Leprosy is a chronic bacterial disease caused by Mycobacterium leprae. Leprosy patients have been found to have defects in T cells activation, which is critical to the clearance of the bacilli. Treg cell suppression is mediated by inhibitory cytokines such as IL10, IL-35 and TGF-ß and its frequency is higher in leprosy patients. Activation and overexpression of programmed death 1 (PD-1) receptor is considered to one of the pathways to inhibit T-cell response in human leprosy. In the current study we address the effect of PD-1 on Tregs function and its immuno-suppressive function in leprosy patients. Flow cytometry was used to evaluate the expression of PD-1 and its ligands on various immune cells T cells, B cells, Tregs and monocytes. We observed higher expression of PD-1 on Tregs is associated with lower production of IL-10 in leprosy patients. PD-1 ligands on T cells, B cells, Tregs and monocytes found to be higher in the leprosy patients as compared to healthy controls. Furthermore, in vitro blocking of PD-1 restores the Tregs mediated suppression of Teff and increase secretion of immunosuppressive cytokine IL-10. Moreover, overexpression of PD-1 positively correlates with disease severity as well as Bacteriological Index (BI) among leprosy patients. Collectively, our data suggested that PD-1 overexpression on various immune cells is associated with disease severity in human leprosy. Manipulation and inhibition of PD-1 signaling pathway on Tregs alter and restore the Treg cell suppression activity in leprosy patients.

Engineering pancreatic islets with a novel form of thrombomodulin protein to overcome early graft loss triggered by instant blood-mediated inflammatory reaction.

The instant blood-mediated inflammatory reaction (IBMIR) is initiated by innate immune responses that cause substantial islet loss after intraportal transplantation. Thrombomodulin (TM) is a multifaceted innate immune modulator. In this study, we report the generation of a chimeric form of thrombomodulin with streptavidin (SA-TM) for transient display on the surface of islets modified with biotin to mitigate IBMIR. SA-TM protein expressed in insect cells showed the expected structural and functional features. SA-TM converted protein C into activated protein C, blocked phagocytosis of xenogeneic cells by mouse macrophages and inhibited neutrophil activation. SA-TM was effectively displayed on the surface of biotinylated islets without a negative effect on their viability or function. Islets engineered with SA-TM showed improved engraftment and established euglycemia in 83% of diabetic recipients when compared with 29% of recipients transplanted with SA-engineered islets as control in a syngeneic minimal mass intraportal transplantation model. Enhanced engraftment and function of SA-TM-engineered islets were associated with the inhibition of intragraft proinflammatory innate cellular and soluble mediators of IBMIR, such as macrophages, neutrophils, high-mobility group box 1, tissue factor, macrophage chemoattractant protein-1, interleukin-1ß, interleukin-6, tumor necrosis factor-α, interferon-γ. Transient display of SA-TM protein on the islet surface to modulate innate immune responses causing islet graft destruction has clinical potential for autologous and allogeneic islet transplantation.

Engineering donor lymphocytes with Fas ligand protein effectively prevents acute graft-versus-host disease.

Alloreactive T-effector cells (Teffs) are the major culprit of acute graft-versus-host disease (aGVHD) associated with hematopoietic stem cell transplantation. Ex vivo nonspecific depletion of T cells from the donor graft impedes stem cell engraftment and posttransplant immune reconstitution. Teffs upregulate Fas after activation and undergo Fas ligand (FasL)-mediated restimulation-induced cell death (RICD), an important mechanism of immune homeostasis. We targeted RICD as a means to eliminate host-reactive Teffs in vivo for the prevention of aGVHD. A novel form of FasL protein chimeric with streptavidin (SA-FasL) was transiently displayed on the surface of biotinylated lymphocytes, taking advantage of the high-affinity interaction between biotin and streptavidin. SA-FasL-engineered mouse and human T cells underwent apoptosis after activation in response to alloantigens in vitro and in vivo. SA-FasL on splenocytes was effective in preventing aGVHD in >70% of lethally irradiated haploidentical mouse recipients after cotransplantation with bone marrow cells, whereas all controls that underwent transplantation with nonengineered splenocytes developed aGVHD. Prevention of aGVHD was associated with an increased ratio of CD4+CD25+FoxP3+ T regulatory (Tregs) to Teffs and significantly reduced transcripts for proinflammatory cytokines in the lymphoid organs and target tissues. Depletion of Tregs from the donor graft abrogated the protection conferred by SA-FasL. This approach was also effective in a xenogeneic aGVHD setting where SA-FasL-engineered human PBMCs were transplanted into NSG mice. Direct display of SA-FasL protein on donor cells as an effective means of eliminating alloreactive Teffs in the host represents a practical approach with significant translation potential for the prevention of aGVHD.

Membrane-coated nanoparticles for direct recognition by T cells.

The direct modulation of T cell responses is an emerging therapeutic strategy with the potential to modulate undesired immune responses including, autoimmune disease, and allogeneic cells transplantation. We have previously demonstrated that poly(lactide-co-glycolide) particles were able to modulate T cell responses indirectly through antigen-presenting cells (APCs). In this report, we investigated the design of nanoparticles that can directly interact and modulate T cells by coating the membranes from APCs onto nanoparticles to form membrane-coated nanoparticles (MCNPs). Proteins within the membranes of the APCs, such as Major Histocompatibility Complex class II and co-stimulatory factors, were effectively transferred to the MCNP. Using alloreactive T cell models, MCNP derived from allogeneic dendritic cells were able to stimulate proliferation, which was not observed with membranes from syngeneic dendritic cells and influenced cytokine secretion. Furthermore, we investigated the engineering of the membranes either on the dendritic cells or postfabrication of MCNP. Engineered membranes could be to promote antigen-specific responses, to differentially activate T cells, or to directly induce apoptosis. Collectively, MCNPs represent a tunable platform that can directly interact with and modulate T cell responses.

A modified surgical procedure using minimally invasive ileocolic vein perfusion in a mouse intrahepatic islet transplant model.

Murine intrahepatic islet transplantation is a clinically relevant but technically challenging surgical procedure because of frequent lethal postoperative bleeding. Here, we describe a protocol for mouse pancreatic islet isolation, purification, and culture. Besides, we also describe a protocol for intrahepatic islet transplantation through the ileocolic vein. Intrahepatic islet transplantation through the ileocolic vein, as opposed to traditional islet perfusion via the main portal vein, has the advantage of improving recovery after surgery and may facilitate islet survival and function in preclinical settings. For complete details on the use and execution of this protocol, please refer to Shrestha et al. (2020).

Effect of drying methods on nut quality of hazelnuts (Corylus avellana L.).

This study was conducted to determine the effects of hazelnut drying machine (DM1 and DM2; at 45 °C and 50 °C, respectively) and sun-drying (concrete ground and grass ground) methods on the chemical properties of Tombul, Palaz, and Ordu Levant hazelnuts. For this purpose, protein, lipid and moisture content, water activity, free fatty acid (FFA), peroxide value (PV), rancimat value (RV) and fatty acid composition were analyzed. As expected, it was observed that monounsaturated fatty acid (MUFA) was the main fatty acid group (81.58-84.80%) followed by polyunsaturated (PUFA; 9.53-11.42%) and saturated fatty acids (SFA; 5.87-6.92%), and the major group constituted ~ 99.00% of the total fatty acids, whereas the minor group constituted ~ 0.5% of these acids. However, caproic (C6: 0), caprylic (C8: 0), capric (C10: 0), lauric (C12: 0), eicosadienoic (20: 2), erucic (22: 1), docosadienoic (22: 2), and lignoceric (C24: 0) fatty acids were below limit of detection (< 0.001%). Samples dried in DM1 and DM2 had more MUFA (84.49%, 84.80, respectively), and lower SFA and PUFA than those using sun-drying methods. Following the drying process, the lowest FFA and PV (0.04-0.17%, 0.00-0.27 meq O2 kg-1, respectively) and the highest RV (5.46-6.05 h) were recorded in the DM1 method. Furthermore, it was also observed that as the heat increased (DM1 and DM2; 45-50 °C, respectively), oleic/linoleic acidity ratio, FFA, and PV increased and iodine value and RV decreased. Therefore, DM1 was thought to be a promising method for hazelnut drying.

The combination of thymoquinone and paclitaxel shows anti-tumor activity through the interplay with apoptosis network in triple-negative breast cancer.

Thymoquinone (TQ) is the active ingredient of Nigella sativa which has a therapeutic potential in cancer therapy and prevention. In this study, TQ has been shown to induce specific cytotoxicity and apoptosis and to inhibit wound healing in triple-negative breast cancer cell line. TQ also inhibited cancer growth in a mouse tumor model. Moreover, TQ and paclitaxel (Pac) combination inhibited cancer growth in cell culture and in mice. Genes involved in TQ and TQ-Pac-mediated cytotoxicity were studied using focused real-time PCR arrays. After bioinformatic analysis, genes in apoptosis, cytokine, and p53 signaling categories were found to be modulated with a high significance in TQ-treated cells (p < 10(-28), p < 10(-8), and p < 10(-6), respectively). Important to note, TQ has been found to regulate the genes involved in the induction of apoptosis through death receptors (p = 5.5 × 10(-5)). Additionally, tumor suppressor genes such as p21, Brca1, and Hic1 were highly upregulated by TQ and TQ-Pac combination. Interestingly, when cells were treated with high dose TQ, several growth factors such as Vegf and Egf were upregulated and several pro-apoptotic factors such as caspases were downregulated possibly pointing out key pathways manipulated by cancer cells to resist against TQ. In cells treated with the combination of TQ and Pac, genes in apoptosis cascade (p < 10(-12)), p53 signaling (p = 10(-5)), and JAK-STAT signaling (p < 10(-3)) were differentially expressed. TQ has also been shown to induce protein levels of cleaved Caspase-3, Caspase-7, and Caspase-12 and PARP and to reduce phosphorylated p65 and Akt1. The in vivo therapeutic potential of TQ-Pac combination and the genetic network involved in this synergy have been shown for the first time to the best of our knowledge.

The Effects of the Angiotensin Converting Enzyme Inhibitor Enalapril and the Angiotensin II Type 1 Receptor Blocker Losartan on Fracture Healing in Rats.

PURPOSE: Angiotensin converting enzyme inhibitors (ACEI) and type I angiotensin receptor blockers (ARB) have been shown to exert significant effects on bone tissue via a local renin-angiotensin-aldosterone system (RAS). The aim of our study was to delineate their influences on fracture healing process. METHODS: Sixty adult male Wistar Albino rats were divided into three groups. After undergoing surgical femoral fracture and fixation, the ACEI group received 10 mg/kg of Enalapril, the ARB group received 10 mg/kg of Losartan and the Control group did not receive any medication. Fracture healing was evaluated at second and fifth postoperative weeks by the Lane-Sandhu radiological staging system and by histological scoring system of Huoet al. ACE expression in fracture callus was studied by immunohistochemistry. RESULTS: Both ACEI and ARB groups showed less fibrous tissue in the fracture area at the second week, but the histologic score differences were significant only between Control and ARB groups. At the fifth week, however, both radiological and histological scores for the ACEI group were significantly higher than both ARB and Control groups, while the scores for ARB and Control groups were similar. The presence of ACE expression in fracture callus was also observed. CONCLUSION: ACEIs had significant positive effects on fracture repair. Losartan failed to display these stimulatory effects, which suggests that local RAS in bone tissue exerts its actions via alternative receptors or pathways than the AT1 receptor.