Tilapia-Derived Granular Hydrogel as a 3D Scaffold Promoting Rapid Wound Healing.

The skin, a crucial organ that protects the body, is vulnerable to external damage. Traditional tissue regeneration methods, including bulk hydrogels, aim to facilitate wound healing by interacting with host cells and providing a conducive environment. However, the nanoscale porosity of conventional hydrogels limits cell penetration and tissue regeneration. To overcome this, hydrogels composed of microgels have emerged as promising alternatives. In this study, we propose a granular hydrogel using decellularized tilapia skin. The tilapia skin-based microgels are cost-effective, immune-friendly, and have a high collagen content. Microgels based on the decellularized extracellular matrix of tilapia were successfully fabricated by using microfluidics. Through the assembly of these microgels using adhesive hyaluronic acid-catechol, the resulting 3D granular hydrogel scaffold facilitated enhanced cell growth, accelerated cell differentiation, and successful healing of full-thickness wounds in a mouse model. This study reveals the potential of tilapia skin-based granular hydrogel assembly in wound healing, overcoming conventional hydrogel limits.

Adipose Lipolysis Regulates Cardiac Glucose Uptake and Function in Mice under Cold Stress.

The heart primarily uses fatty acids as energy substrates. Adipose lipolysis is a major source of fatty acids, particularly under stress conditions. In this study, we showed that mice with selective inactivation of the lipolytic coactivator comparative gene identification-58 (CGI-58) in adipose tissue (FAT-KO mice), relative to their littermate controls, had lower circulating FA levels in the fed and fasted states due to impaired adipose lipolysis. They preferentially utilized carbohydrates as energy fuels and were more insulin sensitive and glucose tolerant. Under cold stress, FAT-KO versus control mice had >10-fold increases in glucose uptake in the hearts but no increases in other tissues examined. Plasma concentrations of atrial natriuretic peptide and cardiac mRNAs for atrial and brain-type natriuretic peptides, two sensitive markers of cardiac remodeling, were also elevated. After one week of cold exposure, FAT-KO mice showed reduced cardiac expression of several mitochondrial oxidative phosphorylation proteins. After one month of cold exposure, hearts of these animals showed depressed functions, reduced SERCA2 protein, and increased proteins for MHC-ß, collagen I proteins, Glut1, Glut4 and phospho-AMPK. Thus, CGI-58-dependent adipose lipolysis critically regulates cardiac metabolism and function, especially during cold adaptation. The adipose-heart axis may be targeted for the management of cardiac dysfunction.

Hepatic NPC1L1 promotes hyperlipidemia in LDL receptor deficient mice.

BACKGROUND AND AIMS: Niemann-Pick C1-like1 (NPC1L1), a crucial cholesterol absorption receptor expressed in human intestine and liver. But in mouse it is only expressed in intestine. Previous studies elucidated that expression of human NPC1L1 in mouse liver led to increase of plasma cholesterol due to activation of absorption from bile. However, hepatic NPC1L1 function was not elucidated in LDL receptor deficient mouse (LDLR-/-) in which LDL was a main lipoprotein as in human. METHODS AND RESULTS: L1-Tg/LDLR-/- mouse was created by crossing liver-specific NPC1L1 transgenic mouse (L1-Tg) with LDLR-/-. L1-Tg/LDLR-/- mice developed hyperlipidemia when fed with atherogenic diet (AD) containing 0.2% cholesterol for 21days. Compared with control mice, biliary cholesterol level in L1-Tg/LDLR-/- mice was significantly lower, plasma cholesterol level was significantly higher in L1-Tg/LDLR-/- mice under both chow diet and AD feeding. New finding in this study is augmentations of plasma TAG L1-Tg/LDLR-/- mice fed with AD. Results were shown that very low density lipoprotein (VLDL) secretion was elevated in L1-Tg/LDLR-/- mice after AD fed. The increase of VLDL secretion was further confirmed by higher expression of hepatic triacylglycerol hydrolase (TGH) and microsomal triglyceride transfer protein (MTP). CONCLUSION: L1-Tg/LDLR-/- mouse is a humanized model to study cholesterol absorption and transportation. The results obtained from L1-Tg/LDLR-/- mouse indicated no feedback mechanism to inhibit NPC1L1 function in liver and hepatic expression of NPC1L1 correlated with VLDL secretion in hypercholesterolemia state.

A test of current models for the mechanism of milk-lipid droplet secretion.

Milk lipid is secreted by a unique process, during which triacylglycerol droplets bud from mammary cells coated with an outer bilayer of apical membrane. In all current schemes, the integral protein butyrophilin 1A1 (BTN) is postulated to serve as a transmembrane scaffold, which interacts either with itself or with the peripheral proteins, xanthine oxidoreductase (XOR) and possibly perilipin-2 (PLIN2), to form an immobile bridging complex between the droplet and apical surface. In one such scheme, BTN on the surface of cytoplasmic lipid droplets interacts directly with BTN in the apical membrane without binding to either XOR or PLIN2. We tested these models using both biochemical and morphological approaches. BTN was concentrated in the apical membrane in all species examined and contained mature N-linked glycans. We found no evidence for the association of unprocessed BTN with intracellular lipid droplets. BTN-enhanced green fluorescent protein was highly mobile in areas of mouse milk-lipid droplets that had not undergone post-secretion changes, and endogenous mouse BTN comprised only 0.5-0.7% (w/w) of the total protein, i.e. over 50-fold less than in the milk-lipid droplets of cow and other species. These data are incompatible with models of milk-lipid secretion in which BTN is the major component of an immobile global adhesive complex and suggest that interactions between BTN and other proteins at the time of secretion are more transient than previously predicted. The high mobility of BTN in lipid droplets marks it as a potential mobile signaling molecule in milk.

NPC1L1 knockout protects against colitis-associated tumorigenesis in mice.

BACKGROUND: Colorectal cancer is strongly associated with lipid metabolism. NPC1L1, a sterol transporter, plays a key role in modulating lipid homeostasis in vivo. Its inhibitor, ezetimibe, began to be used clinically to lower cholesterol and this caused the great debate on its role in causing carcinogenesis. Here we explored the role of NPC1L1 in colorectal tumorigenesis. METHODS: Wild-type mice and NPC1L1(-/-) (NPC1L1 knockout) mice were treated with azoxymethane (AOM)-dextran sodium sulfate (DSS) to induce colitis-associated colorectal tumorigenesis. Mice were sacrificed 10, 15, 18 or 20 weeks after AOM treatment, respectively. Colorectal tumors were counted and analyzed. Plasma lipid concentrations were measured using enzymatic reagent kit. Protein expression level was assayed by western blot. RESULTS: NPC1L1(-/-) mice significantly had fewer tumors than wild-type. The ratio of malignant/tumor in NPC1L1(-/-) mice was significantly lower than in wild-type 20 weeks after AOM-DSS treatment. NPC1L1 was highly expressed in the small intestine of wild-type mice but its expression was undetectable in colorectal mucous membranes or tumors in either group. NPC1L1 knockout decreased plasma total cholesterol and phospholipid. NPC1L1(-/-) mice had significant lower intestinal inflammation scores and expressed inflammatory markers p-c-Jun, p-ERK and Caspase-1 p20 lower than wild-type. NPC1L1 knockout also reduced lymphadenectasis what may be caused by inflammation. NPC1L1 knockout in mice decreased ß-catenin in tumors and regulated TGF-ß and p-gp in adjacent colons or tumors. There was not detectable change of p53 by NPC1L1 knockout. CONCLUSIONS: Our results provide the first evidence that NPC1L1 knockout protects against colitis-associated tumorigenesis. NPC1L1 knockout decreasing plasma lipid, especially cholesterol, to reduce inflammation and decreasing ß-catenin, p-c-Jun and p-ERK may be involved in the mechanism.

ROS-Scavenging Lignin-Based Tolerogenic Nanoparticle Vaccine for Treatment of Multiple Sclerosis.

Multiple sclerosis (MS) is a demyelinating autoimmune disease, in which the immune system attacks myelin. Although systemic immunosuppressive agents have been used to treat MS, long-term treatment with these drugs causes undesirable side effects such as altered glucose metabolism, insomnia, and hypertension. Herein, we propose a tolerogenic therapeutic vaccine to treat MS based on lignin nanoparticles (LNP) with intrinsic reactive oxygen species (ROS)-scavenging capacity derived from their phenolic moieties. The LNP loaded with autoantigens of MS allowed for inducing tolerogenic DCs with low-level expression of costimulatory molecules while presenting antigenic peptides. Intravenous injection of an LNP-based tolerogenic vaccine into an experimental autoimmune encephalomyelitis (EAE) model led to durable antigen-specific immune tolerance via inducing regulatory T cells (Tregs). Autoreactive T helper type 1 cells, T helper type 17 cells, and inflammatory antigen presentation cells (APCs) were suppressed in the central nervous system (CNS), ameliorating ongoing MS in early and late disease states. Additionally, the incorporation of dexamethasone into an LNP-based tolerogenic nanovaccine could further improve the recovery of EAE mice in the severe chronic stage. As lignin is the most abundant biomass and waste byproduct in the pulping industry, a lignin-based tolerogenic vaccine could be a novel, cost-effective, high-value vaccine platform with potent therapeutic efficiency in treating autoimmune diseases.

Efficient triplet exciton confinement of blue- and white-organic light emitting diodes using a new host material.

We have demonstrated lower driving voltage and efficient blue phosphorescent organic light emitting diodes (PHOLEDs) using iridium(III) bis[(4,6-di-fluoropheny)-pyridinato-N,C2] picolinate (Flrpic) doped in new host material 9-(4-(triphenylsilyl)phenyl)-9H-carbazole (SPC) and 2,2',2"-(1,3,5-benzenetryl)tris(1-phenyl)-1H-benzimidazol (TPBi) as double-emitting layer (D-EML) system. The D-EML was employed to have good electron transportability and exciton confinement. Additionally, we fabricated white organic light-emitting diode (WOLED) using a phosphorescent red emitter; bis(2-phenylquinolinato)-acetylacetonate iridium III (Ir(pq)2acac) doped in SPC and TPBi as D-EML. The properties of white device exhibited a maximum luminous efficiency of 19.03 cd/A, a maximum external quantum efficiency of 9.91%, and a maximum power efficiency of 12.30 lm/W. It also showed white emission with CIE(x,y) coordinates of (x = 0.38, y = 0.37) at 8 V.

Nanoparticle-based non-viral CRISPR delivery for enhanced immunotherapy.

The CRISPR Cas9 system has received considerable attention due to its simplicity, efficiency, and high precision for gene editing. The development of various therapeutic applications of the CRISPR system is under active research. In particular, its proven effects and promise in immunotherapy are of note. CRISPR/Cas9 components can be transported in various forms, such as plasmid DNA, mRNA of the Cas9 protein with gRNA, or a ribonucleoprotein complex. Even with its proven gene editing superiority, there are limitations in delivering the CRISPR system to target cells. CRISPR systems can be delivered via physical methods, viral vectors, or non-viral carriers. The development of diverse types of nanoparticles that could be used as non-viral carriers could overcome the disadvantages of physical techniques and viral vectors such as low cell viability, induction of immune response, limited loading capacity, and lack of targeting ability. Herein, we review the recent developments in applications of CRISPR system-mediated non-viral carriers in immunotherapy, depending on the targeting cell types, and discuss future research directions.

A mouse pancreatic organoid model to compare PD-L1 blocking antibodies.

Immune checkpoint inhibitors (ICIs) have changed the therapeutic landscape for cancer patients, but diabetes, a rare, severe immune-related endocrinopathy, is linked to ICI therapy. It is unclear whether glycosylation of ICIs may play a role in the development of this adverse event and how the physiological effects of different ICIs on pancreatic cells should be evaluated. We used a mouse pancreatic organoid model to compare three PD-L1 blocking antibodies in the presence or absence of IFNγ using a metabolic bioanalyzer. Modulation of ICI glycosylation altered its metabolic effects on mouse pancreatic organoids, suggesting that this model could be used to monitor and compare ICIs and to study the mechanisms underlying the development of IC-mediated diabetes.

Superstrong, superstiff, and conductive alginate hydrogels.

For the practical use of synthetic hydrogels as artificial biological tissues, flexible electronics, and conductive membranes, achieving requirements for specific mechanical properties is one of the most prominent issues. Here, we demonstrate superstrong, superstiff, and conductive alginate hydrogels with densely interconnecting networks implemented via simple reconstructing processes, consisting of anisotropic densification of pre-gel and a subsequent ionic crosslinking with rehydration. The reconstructed hydrogel exhibits broad ranges of exceptional tensile strengths (8-57 MPa) and elastic moduli (94-1,290 MPa) depending on crosslinking ions. This hydrogel can hold sufficient cations (e.g., Li+) within its gel matrix without compromising the mechanical performance and exhibits high ionic conductivity enough to be utilized as a gel electrolyte membrane. Further, this strategy can be applied to prepare mechanically outstanding, ionic-/electrical-conductive hydrogels by incorporating conducting polymer within the hydrogel matrix. Such hydrogels are easily laminated with strong interfacial adhesion by superficial de- and re-crosslinking processes, and the resulting layered hydrogel can act as a stable gel electrolyte membrane for an aqueous supercapacitor.

Immunosuppressive biomaterial-based therapeutic vaccine to treat multiple sclerosis via re-establishing immune tolerance.

Current therapies for autoimmune diseases, such as multiple sclerosis (MS), induce broad suppression of the immune system, potentially promoting opportunistic infections. Here, we report an immunosuppressive biomaterial-based therapeutic vaccine carrying self-antigen and tolerance-inducing inorganic nanoparticles to treat experimental autoimmune encephalomyelitis (EAE), a mouse model mimicking human MS. Immunization with self-antigen-loaded mesoporous nanoparticles generates Foxp3+ regulatory T-cells in spleen and systemic immune tolerance in EAE mice, reducing central nervous system-infiltrating antigen-presenting cells (APCs) and autoreactive CD4+ T-cells. Introducing reactive oxygen species (ROS)-scavenging cerium oxide nanoparticles (CeNP) to self-antigen-loaded nanovaccine additionally suppresses activation of APCs and enhances antigen-specific immune tolerance, inducing recovery in mice from complete paralysis at the late, chronic stage of EAE, which shows similarity to chronic human MS. This study clearly shows that the ROS-scavenging capability of catalytic inorganic nanoparticles could be utilized to enhance tolerogenic features in APCs, leading to antigen-specific immune tolerance, which could be exploited in treating MS.

Targeting specificity of APOBEC-based cytosine base editor in human iPSCs determined by whole genome sequencing.

DNA base editors have enabled genome editing without generating DNA double strand breaks. The applications of this technology have been reported in a variety of animal and plant systems, however, their editing specificity in human stem cells has not been studied by unbiased genome-wide analysis. Here we investigate the fidelity of cytidine deaminase-mediated base editing in human induced pluripotent stem cells (iPSCs) by whole genome sequencing after sustained or transient base editor expression. While base-edited iPSC clones without significant off-target modifications are identified, this study also reveals the potential of APOBEC-based base editors in inducing unintended point mutations outside of likely in silico-predicted CRISPR-Cas9 off-targets. The majority of the off-target mutations are C:G->T:A transitions or C:G->G:C transversions enriched for the APOBEC mutagenesis signature. These results demonstrate that cytosine base editor-mediated editing may result in unintended genetic modifications with distinct patterns from that of the conventional CRISPR-Cas nucleases.

What activates thermogenesis when lipid droplet lipolysis is absent in brown adipocytes?

Cold exposure activates the sympathetic nervous system. It is generally thought that this sympathetic activation induces heat production by stimulating lipolysis of cytosolic lipid droplets (LDs) in brown adipocytes. However, this concept was not examined in vivo due to lack of appropriate animal models. Recently, we and others have demonstrated that LD lipolysis in brown adipocytes is not required for cold-induced nonshivering thermogenesis. Our studies uncovered an essential role of white adipose tissue (WAT) lipolysis in fueling thermogenesis during fasting. In addition, we showed that lipolysis deficiency in brown adipose tissue (BAT) induces WAT browning. This commentary further discusses the significance of our findings and how whole body may be heated up without BAT lipolysis.

Lipolysis in Brown Adipocytes Is Not Essential for Cold-Induced Thermogenesis in Mice.

Lipid droplet (LD) lipolysis in brown adipose tissue (BAT) is generally considered to be required for cold-induced nonshivering thermogenesis. Here, we show that mice lacking BAT Comparative Gene Identification-58 (CGI-58), a lipolytic activator essential for the stimulated LD lipolysis, have normal thermogenic capacity and are not cold sensitive. Relative to littermate controls, these animals had higher body temperatures when they were provided food during cold exposure. The increase in body temperature in the fed, cold-exposed knockout mice was associated with increased energy expenditure and with increased sympathetic innervation and browning of white adipose tissue (WAT). Mice lacking CGI-58 in both BAT and WAT were cold sensitive, but only in the fasted state. Thus, LD lipolysis in BAT is not essential for cold-induced nonshivering thermogenesis in vivo. Rather, CGI-58-dependent LD lipolysis in BAT regulates WAT thermogenesis, and our data uncover an essential role of WAT lipolysis in fueling thermogenesis during fasting.