The generation of PD-L1 and PD-L2 in cancer cells: From nuclear chromatin reorganization to extracellular presentation

The immune checkpoint blockade (ICB) targeting on PD-1/PD-L1 has shown remarkable promise in treating cancers. However, the low response rate and frequently observed severe side effects limit its broad benefits. It is partially due to less understanding of the biological regulation of PD-L1. Here, we systematically and comprehensively summarized the regulation of PD-L1 from nuclear chromatin reorganization to extracellular presentation. In PD-L1 and PD-L2 highly expressed cancer cells, a new TAD (topologically associating domain) (chr9: 5,400,000-5,600,000) around CD274 and CD273 was discovered, which includes a reported super-enhancer to drive synchronous transcription of PD-L1 and PD-L2. The re-shaped TAD allows transcription factors such as STAT3 and IRF1 recruit to PD-L1 locus in order to guide the expression of PD-L1. After transcription, the PD-L1 is tightly regulated by miRNAs and RNA-binding proteins via the long 3'UTR. At translational level, PD-L1 protein and its membrane presentation are tightly regulated by post-translational modification such as glycosylation and ubiquitination. In addition, PD-L1 can be secreted via exosome to systematically inhibit immune response. Therefore, fully dissecting the regulation of PD-L1/PD-L2 and thoroughly detecting PD-L1/PD-L2 as well as their regulatory networks will bring more insights in ICB and ICB-based combinational therapy.

Bioresponsive immune-booster-based prodrug nanogel for cancer immunotherapy

The combination of chemotherapy and immunotherapy motivates a potent immune system by triggering immunogenic cell death (ICD), showing great potential in inhibiting tumor growth and improving the immunosuppressive tumor microenvironment (ITM). However, the therapeutic effectiveness has been restricted by inferior drug bioavailability. Herein, we reported a universal bioresponsive doxorubicin (DOX)-based nanogel to achieve tumor-specific co-delivery of drugs. DOX-based mannose nanogels (DM NGs) was designed and choosed as an example to elucidate the mechanism of combined chemo-immunotherapy. As expected, the DM NGs exhibited prominent micellar stability, selective drug release and prolonged survival time, benefited from the enhanced tumor permeability and prolonged blood circulation. We discovered that the DOX delivered by DM NGs could induce powerful anti-tumor immune response facilitated by promoting ICD. Meanwhile, the released mannose from DM NGs was proved as a powerful and synergetic treatment for breast cancer in vitro and in vivo, via damaging the glucose metabolism in glycolysis and the tricarboxylic acid cycle. Overall, the regulation of tumor microenvironment with DOX-based nanogel is expected to be an effectual candidate strategy to overcome the current limitations of ICD-based immunotherapy, offering a paradigm for the exploitation of immunomodulatory nanomedicines.

The biology, function, and applications of exosomes in cancer

Exosomes are cell-derived nanovesicles with diameters from 30 to 150 nm, released upon fusion of multivesicular bodies with the cell surface. They can transport nucleic acids, proteins, and lipids for intercellular communication and activate signaling pathways in target cells. In cancers, exosomes may participate in growth and metastasis of tumors by regulating the immune response, blocking the epithelial-mesenchymal transition, and promoting angiogenesis. They are also involved in the development of resistance to chemotherapeutic drugs. Exosomes in liquid biopsies can be used as non-invasive biomarkers for early detection and diagnosis of cancers. Because of their amphipathic structure, exosomes are natural drug delivery vehicles for cancer therapy.

Microneedle-based devices for point-of-care infectious disease diagnostics

Recent infectious disease outbreaks, such as COVID-19 and Ebola, have highlighted the need for rapid and accurate diagnosis to initiate treatment and curb transmission. Successful diagnostic strategies critically depend on the efficiency of biological sampling and timely analysis. However, current diagnostic techniques are invasive/intrusive and present a severe bottleneck by requiring specialist equipment and trained personnel. Moreover, centralised test facilities are poorly accessible and the requirement to travel may increase disease transmission. Self-administrable, point-of-care (PoC) microneedle diagnostic devices could provide a viable solution to these problems. These miniature needle arrays can detect biomarkers in/from the skin in a minimally invasive manner to provide (near-) real-time diagnosis. Few microneedle devices have been developed specifically for infectious disease diagnosis, though similar technologies are well established in other fields and generally adaptable for infectious disease diagnosis. These include microneedles for biofluid extraction, microneedle sensors and analyte-capturing microneedles, or combinations thereof. Analyte sampling/detection from both blood and dermal interstitial fluid is possible. These technologies are in their early stages of development for infectious disease diagnostics, and there is a vast scope for further development. In this review, we discuss the utility and future outlook of these microneedle technologies in infectious disease diagnosis.

Uptake and trafficking of different sized PLGA nanoparticles by dendritic cells in imiquimod-induced psoriasis-like mice model

Psoriasis is an autoimmune inflammatory disease, where dendritic cells (DCs) play an important role in its pathogenesis. In our previous work, we have demonstrated that topical delivery of curcumin-loaded poly (lactic-

Protective role of berberine on ulcerative colitis through modulating enteric glial cells-intestinal epithelial cells-immune cells interactions

Ulcerative colitis (UC) manifests as an etiologically complicated and relapsing gastrointestinal disease. The enteric nervous system (ENS) plays a pivotal role in rectifying and orchestrating the inflammatory responses in gut tract. Berberine, an isoquinoline alkaloid, is known as its anti-inflammatory and therapeutic effects in experimental colitis. However, little research focused on its regulatory function on ENS. Therefore, we set out to explore the pathological role of neurogenic inflammation in UC and the modulating effects of berberine on neuro-immune interactions. Functional defects of enteric glial cells (EGCs), with decreased glial fibrillary acidic protein (GFAP) and increased substance P expression, were observed in DSS-induced murine UC. Administration of berberine can obviously ameliorate the disease severity and restore the mucosal barrier homeostasis of UC, closely accompanying by maintaining the residence of EGCs and attenuating inflammatory infiltrations and immune cells overactivation. , berberine showed direct protective effects on monoculture of EGCs, bone marrow-derived dendritic cells (BMDCs), T cells, and intestinal epithelial cells (IECs) in the simulated inflammatory conditions. Furthermore, berberine could modulate gut EGCs-IECs-immune cell interactions in the co-culture systems. In summary, our study indicated the EGCs-IECs-immune cell interactions might function as a crucial paradigm in mucosal inflammation and provided an infusive mechanism of berberine in regulating enteric neurogenic inflammation.

Recent progress of hypoxia-modulated multifunctional nanomedicines to enhance photodynamic therapy: opportunities, challenges, and future development

Hypoxia, a salient feature of most solid tumors, confers invasiveness and resistance to the tumor cells. Oxygen-consumption photodynamic therapy (PDT) suffers from the undesirable impediment of local hypoxia in tumors. Moreover, PDT could further worsen hypoxia. Therefore, developing effective strategies for manipulating hypoxia and improving the effectiveness of PDT has been a focus on antitumor treatment. In this review, the mechanism and relationship of tumor hypoxia and PDT are discussed. Moreover, we highlight recent trends in the field of nanomedicines to modulate hypoxia for enhancing PDT, such as oxygen supply systems, down-regulation of oxygen consumption and hypoxia utilization. Finally, the opportunities and challenges are put forward to facilitate the development and clinical transformation of PDT.

Red blood cell membrane-camouflaged nanoparticles: a novel drug delivery system for antitumor application

Erythrocytes (red blood cells, RBCs) are the most abundant circulating cells in the blood and have been widely used in drug delivery systems (DDS) because of their features of biocompatibility, biodegradability, and long circulating half-life. Accordingly, a "camouflage" comprised of erythrocyte membranes renders nanoparticles as a platform that combines the advantages of native erythrocyte membranes with those of nanomaterials. Following injection into the blood of animal models, the coated nanoparticles imitate RBCs and interact with the surroundings to achieve long-term circulation. In this review, the biomimetic platform of erythrocyte membrane-coated nano-cores is described with regard to various aspects, with particular focus placed on the coating mechanism, preparation methods, verification methods, and the latest anti-tumor applications. Finally, further functional modifications of the erythrocyte membranes and attempts to fuse the surface properties of multiple cell membranes are discussed, providing a foundation to stimulate extensive research into multifunctional nano-biomimetic systems.