Innovative Tissue-Engineered Strategies for Osteochondral Defect Repair and Regeneration: Current Progress and Challenges

Clinical treatments for the repair of osteochondral defects (OCD) are merely palliative, not completely curative, and thus enormously unfulfilled challenges. With the in-depth studies of biology, medicine, materials, and engineering technology, the conception of OCD repair and regeneration should be renewed. During the past decades, many innovative tissue-engineered approaches for repairing and regenerating damaged osteochondral units have been widely explored. Various scaffold-free and scaffold-based strategies, such as monophasic, biphasic, and currently fabricated multiphasic and gradient architectures have been proposed and evaluated. Meanwhile, progenitor cells and tissue-specific cells have also been intensively investigated in vivo as well as ex vivo. Concerning bioactive factors and drugs, they have been combined with scaffolds and/or living cells, and even released in a spatiotemporally controlled manner. Although tremendous progress has been achieved, further research and development (R&D) is needed to convert preclinical outcomes into clinical applications. Here, the osteochondral unit structure, its defect classifications, and diagnosis are summarized. Commonly used clinical reparative techniques, tissue-engineered strategies, emerging 3D-bioprinting technologies, and the status of their clinical applications are discussed. Existing challenges to translation are also discussed and potential solutions for future R&D directions are proposed.

Tectoridin Stimulates the Activity of Human Dermal Papilla Cells and Promotes Hair Shaft Elongation in Mouse Vibrissae Hair Follicle Culture

To search hair growth-promoting herbal extract, a screening platform of having HEK293T fibroblast being transfected with pTOPFLASH DNA construct was developed over a thousand of herbal extracts and phytochemicals were screened. One of the hits was ethanolic extract of Rhizoma Belamcandae, the rhizome of Belamcanda chinensis (L.) DC. Tectoridin, an isoflavone from Rhizoma Belamcandae, was shown to be responsible for this activation of promoter construct, inducing the transcription of pTOPFLASH in the transfected fibroblasts in a dose-dependent manner. The blockage by DKK-1 suggested the action of tectoridin could be mediated by the Wnt receptor. The hair growth-promoting effects of tectoridin were illustrated in human follicular dermal papilla cells and mouse vibrissae organ cultures. In tectoridin-treated dermal papilla cultures, an activation of Wnt signaling was demonstrated by various indicative markers, including TCF/LEF1 transcriptional activity, nuclear translocation of β-catenin, expressions level of mRNAs encoding axin-related protein, (AXIN2), β-catenin, lymphoid enhancer-binding factor-1 (LEF-1), insulin-like growth factor 1 (IGF-1) and alkaline phosphatase (ALP). In addition, an increase of hair shaft elongation was observed in cultured mouse vibrissae upon the treatment of tectoridin. Tectoridin, as well as the herbal extract of Rhizoma Belamcandae, possesses hair promoting activity, which deserves further development.

Predicting standardized absolute returns using rolling-sample textual modelling

Understanding how textual information impacts financial market volatility has been one of the growing topics in financial econometric research. In this paper, we aim to examine the relationship between the volatility measure that is extracted from GARCH modelling and textual news information both publicly available and from subscription, and the performances of the two datasets are compared. We utilize a latent Dirichlet allocation method to capture the dynamic features of the textual data overtime by summarizing their statistical outputs, such as topic distributions in documents and word distributions in topics. In addition, we transform various measures representing the popularity and diversity of topics to form predictors for a rolling regression model to assess the usefulness of textual information. The proposed method captures the statistical properties of textual information over different time periods and its performance is evaluated in an out-of-sample analysis. Our results show that the topic measures are more useful for predicting our volatility proxy, the unexplained variance from the GARCH model than the simple moving average. The finding indicates that our method is helpful in extracting significant textual information to improve the prediction of stock market volatility.

Aptamer-functionalized triptolide with release controllability as a promising targeted therapy against triple-negative breast cancer

Targeted delivery and precise release of toxins is a prospective strategy for the treatment of triple-negative breast cancer (TNBC), yet the flexibility to incorporate both properties simultaneously remains tremendously challenging in the X-drug conjugate fields. As critical components in conjugates, linkers could flourish in achieving optimal functionalities. Here, we pioneered a pH-hypersensitive tumor-targeting aptamer AS1411-triptolide conjugate (AS-TP) to achieve smart release of the toxin and targeted therapy against TNBC. The multifunctional acetal ester linker in the AS-TP site-specifically blocked triptolide toxicity, quantitatively sustained aptamer targeting, and ensured the circulating stability. Furthermore, the aptamer modification endowed triptolide with favorable water solubility and bioavailability and facilitated endocytosis of conjugated triptolide by TNBC cells in a nucleolin-dependent manner. The integrated superiorities of AS-TP promoted the preferential intra-tumor triptolide accumulation in xenografted TNBC mice and triggered the in-situ triptolide release in the weakly acidic tumor microenvironment, manifesting striking anti-TNBC efficacy and virtually eliminated toxic effects beyond clinical drugs. This study illustrated the therapeutic potential of AS-TP against TNBC and proposed a promising concept for the development of nucleic acid-based targeted anticancer drugs.

Acetylcholinesterase is regulated by exposure of ultraviolet B in skin keratinocytes: A potential inducer of cholinergic urticaria

Cholinergic urticaria is a dermatological disease characterized by the presence of large patches of red skin and transient hives triggered by factors, such as exercise, sweating, and psychological tension. This skin problem is hypothesized to be attributed to a reduced expression of acetylcholinesterase (AChE), an enzyme responsible for hydrolyzing acetylcholine (ACh). Consequently, ACh is thought to the leak from sympathetic nerves to skin epidermis. The redundant ACh stimulates the mast cells to release histamine, triggering immune responses in skin. Here, the exposure of ultraviolet B in skin suppressed the expression of AChE in keratinocytes, both in in vivo and in vitro models. The decrease of the enzyme was resulted from a declined transcription of ACHE gene mediated by micro-RNAs, that is, miR-132 and miR-212. The levels of miR-132 and miR-212 were markedly induced by exposure to ultraviolet B, which subsequently suppressed the transcriptional rate of ACHE. In the presence of low level of AChE, the overflow ACh caused the pro-inflammatory responses in skin epidermis, including increased secretion of cytokines and COX-2. These findings suggest that ultraviolet B exposure is one of the factors contributing to cholinergic urticaria in skin.

Design, Synthesis, and Biological Evaluations of a Novel Resveratrol-Type Analogue Against VEGF

Vascular endothelial growth factor (VEGF), also known as VEGF-A, has been reported to mediate various diseases, including cancer and wet age-related macular degeneration (wAMD). Despite the fact that VEGF inhibitors are commercially available and appear to be effective in clinical applications, adverse effects have been caused by these treatments. There is an unmet need for developing novel VEGF-targeted treatments against these diseases. Resveratrol, a phytochemical derived from fruits and vegetables, has shown promising potency in suppressing VEGF-mediated bioactivities through a series of in vitro and in vivo testing models. Herein, we report that RE-1, a synthetic resveratrol-type analog, displays robust inhibitory activities against VEGF and its downstream signaling pathways, surpassing its parental molecule, resveratrol. In addition, the drug capabilities of RE-1 were evaluated. As a newly synthesized chemical, RE-1 could be considered for subsequent pharmacological development targeting VEGF-related diseases.

Cholinergic Signaling Mediated by Muscarinic Receptors Triggers the Ultraviolet-Induced Release of Melanosome in Cultured Melanoma Cells

In skin, melanin is synthesized and stored in melanosomes. In epidermal melanocytes, melanosomes are transported to and internalized by the neighboring keratinocytes, subsequently leading to skin pigmentation. Ultraviolet (UV) radiation induces the release of acetylcholine (ACh) from keratinocytes, which in turn activates ACh receptors (AChRs) on nearby melanocytes, forming a proposed "skin synapse". Here, we illustrated that the UV-induced melanosome release from cultured B16F10 melanoma cells could be mediated by co-actions of ACh. In the cell cultures, UV exposure robustly elicited melanosome release. Applied bethanechol (BeCh), an agonist of muscarinic AChR (mAChR), could significantly enhance the release. In parallel, the intracellular Ca2+ mobilization was regulated. The applied antagonists of M1 and/or M3 mAChRs could block the UV-induced melanosome release and the mobilization of intracellular Ca2+. The phosphorylation of PKC, triggered by UV and BeCh treatments, could be suppressed by the applied mAChR antagonists. The expressions of tethering complex for exocytosis, for example, Sec8, Exo70, and Rab11b, as well as synaptotagmin, were increased under UV exposure together with mAChR agonist: The inductions were fully abolished by M1 or M3 antagonist. Here, we hypothesize that the cholinergic signaling is playing roles in UV-induced exocytosis of melanosomes.

A moving-window bayesian network model for assessing systemic risk in financial markets

Systemic risk refers to the uncertainty that arises due to the breakdown of a financial system. The concept of "too connected to fail" suggests that network connectedness plays an important role in measuring systemic risk. In this paper, we first recover a time series of Bayesian networks for stock returns, which allow the direction of links among stock returns to be formed with Markov properties in directed graphs. We rank the stocks in the time series of Bayesian networks based on the topological orders of the stocks in the learned Bayesian networks and develop an order distance, a new measure with which to assess the changes in the topological orders of the stocks. In an empirical study using stock data from the Hang Seng Index in Hong Kong and the Dow Jones Industrial Average, we use the order distance to predict the extreme absolute return, which is a proxy of extreme market risks, or a signal of systemic risks, using the LASSO regression model. Our results indicate that the network statistics of the time series of Bayesian networks and the order distance substantially improve the predictability of extreme absolute returns and provide insights into the assessment of systemic risk.

Platelet-Rich Plasma Extract Derived from Animals Shows Potential in Promoting Wound Healing and Suppressing Inflammatory Response in Skin Cells

Platelet-rich plasma (PRP) is an extract enriched with growth factors that facilitate skin regeneration and rejuvenation. Here, the functionalities of PRP derived from various animal sources have been investigated and compared, focusing on its potential therapeutic applications in skin regeneration. Total antioxidant capacity, wound closure, and melanin content in cultured keratinocytes were used to evaluate the efficacy of different animal PRP sources. The PRP derived from deer exhibited the highest performance and was selected for subsequent proteomic and metabolomic analyses. Our findings indicate that deer blood is an optimal source of animal-derived PRP, demonstrating significant properties in promoting wound healing, anti-inflammatory responses, and skin regeneration. This identified PRP from deer sources can be developed as a safe and effective product for skin rejuvenation and regeneration.