Lysosomal Degradation Pathway Research Articles

Platinum‐Metformin Conjugates Acting as Promising PD‐L1 Inhibitors through the AMP‐Activated Protein Kinase Mediated Lysosomal Degradation Pathway

AbstractWith the development of metalloimmunology, the potential of platinum drugs in cancer immunotherapy has attracted extensive attention. Although immunochemotherapy combining PD‐1/PD−L1 antibodies with platinum drugs has achieved great success in the clinic, combination therapy commonly brings new problems. Herein, we have developed a platinum‐metformin conjugate as a promising alternative to antibody‐based PD−L1 inhibitors, not only disrupting PD‐1/PD−L1 axis on cell surface but also down‐regulating the total PD−L1 levels in non‐small cell lung cancer (NSCLC) cells comprehensively, thus achieving highly efficient immunochemotherapy by a single small molecule. Mechanism studies demonstrate that Pt‐metformin conjugate can selectively accumulate in lysosomes, promote lysosomal‐dependent PD−L1 degradation via the AMPK‐TFEB pathway, and modulate the upstream regulatory proteins related to PD−L1 expression (e.g. HIF‐1α and NF‐κB), eventually decreasing the total abundance of PD−L1 in NSCLC, overcoming tumor hypoxia, and activating anti‐tumor immunity in vivo. This work suggests an AMPK‐mediated lysosomal degradation pathway of PD−L1 for the first time and provides a unique design perspective for the development of novel platinum drugs for immunochemotherapy.

Pharmacology of natural bioactive compounds used for management of Huntington diseases: An overview

Huntington's disease (HtD), an inherited genetic neurodegenerative disorder, posed threat to elderly population world-wide. HtD is caused by the repetition of cytosine-adenine-guanine (CAG) in HtD gene, which further leads to the formation of a mutant Huntington (mHtt) protein that is responsible for neuronal dysfunction and cell death. Symptoms of HtD usually begin in adulthood and progress slowly, resulting in psychiatric disturbances, motor deficits and cognitive dysfunction. The medium spiny neurons of the striatum and cortex are mainly affected in HtD. Multiple hypotheses have been proposed to elucidate the underlying mechanisms that lead to neuronal dysfunction and cell death. This typically includes molecular genetics, oxidative stress (OS), excitotoxicity, mitochondrial impairment etc. Natural bioactives are a diverse group of compounds derived from plants, animals and microorganisms. They have been found to modulate multiple signaling pathways involved in the development of HtD and have potentials in reducing OS, neuroinflammation, and neuronal death, which are key pathological processes in HtD.Mostly natural bioactive offers protection either by down-regulating the OS, excitotoxicity, mitochondrial dysfunctions, microglial inactivation, neuroinflammation and/or by upregulating ubiquitin-proteasome system, autophagy & lysosomal degradation pathway, apoptotic pathway, purinergic signaling pathway.In this chapter, we have summarized various natural bioactives that exhibit therapeutic potential against HtD. Furthermore, we have discussed the opportunities and challenges associated with the development of safe and effective natural bioactives-based therapies against HtD.

Apache is a neuronal player in autophagy required for retrograde axonal transport of autophagosomes

Neurons are dependent on efficient quality control mechanisms to maintain cellular homeostasis and function due to their polarization and long-life span. Autophagy is a lysosomal degradative pathway that provides nutrients during starvation and recycles damaged and/or aged proteins and organelles. In neurons, autophagosomes constitutively form in distal axons and at synapses and are trafficked retrogradely to the cell soma to fuse with lysosomes for cargo degradation. How the neuronal autophagy pathway is organized and controlled remains poorly understood. Several presynaptic endocytic proteins have been shown to regulate both synaptic vesicle recycling and autophagy. Here, by combining electron, fluorescence, and live imaging microscopy with biochemical analysis, we show that the neuron-specific protein APache, a presynaptic AP-2 interactor, functions in neurons as an important player in the autophagy process, regulating the retrograde transport of autophagosomes. We found that APache colocalizes and co-traffics with autophagosomes in primary cortical neurons and that induction of autophagy by mTOR inhibition increases LC3 and APache protein levels at synaptic boutons. APache silencing causes a blockade of autophagic flux preventing the clearance of p62/SQSTM1, leading to a severe accumulation of autophagosomes and amphisomes at synaptic terminals and along neurites due to defective retrograde transport of TrkB-containing signaling amphisomes along the axons. Together, our data identify APache as a regulator of the autophagic cycle, potentially in cooperation with AP-2, and hypothesize that its dysfunctions contribute to the early synaptic impairments in neurodegenerative conditions associated with impaired autophagy.

Platinum-Metformin Conjugates Acting as Promising PD-L1 Inhibitors through the AMP-Activated Protein Kinase Mediated Lysosomal Degradation Pathway.

With the development of metalloimmunology, the potential of platinum drugs in cancer immunotherapy has attracted extensive attention. Although immunochemotherapy combining PD-1/PD-L1 antibodies with platinum drugs has achieved great success in the clinic, combination therapy commonly brings new problems. Herein, we have developed a platinum-metformin conjugate as a promising alternative to antibody-based PD-L1 inhibitors, not only disrupting PD-1/PD-L1 axis on cell surface but also down-regulating the total PD-L1 levels in non-small cell lung cancer (NSCLC) cells comprehensively, thus achieving highly efficient immunochemotherapy by a single small molecule. Mechanism studies demonstrate that Pt-metformin conjugate can selectively accumulate in lysosomes, promote lysosomal-dependent PD-L1 degradation via the AMPK-TFEB pathway, and modulate the upstream regulatory proteins related to PD-L1 expression (e.g. HIF-1α and NF-κB), eventually decreasing the total abundance of PD-L1 in NSCLC, overcoming tumor hypoxia, and activating anti-tumor immunity in vivo. This work suggests an AMPK-mediated lysosomal degradation pathway of PD-L1 for the first time and provides a unique design perspective for the development of novel platinum drugs for immunochemotherapy.

Reconstitution of BNIP3/NIX-mediated autophagy reveals two pathways and hierarchical flexibility of the initiation machinery.

Selective autophagy is a lysosomal degradation pathway that is critical for maintaining cellular homeostasis by disposing of harmful cellular material. While the mechanisms by which soluble cargo receptors recruit the autophagy machinery are becoming increasingly clear, the principles governing how organelle-localized transmembrane cargo receptors initiate selective autophagy remain poorly understood. Here, we demonstrate that transmembrane cargo receptors can initiate autophagosome biogenesis not only by recruiting the upstream FIP200/ULK1 complex but also via a WIPI-ATG13 complex. This latter pathway is employed by the BNIP3/NIX receptors to trigger mitophagy. Additionally, other transmembrane mitophagy receptors, including FUNDC1 and BCL2L13, exclusively use the FIP200/ULK1 complex, while FKBP8 and the ER-phagy receptor TEX264 are capable of utilizing both pathways to initiate autophagy. Our study defines the molecular rules for initiation by transmembrane cargo receptors, revealing remarkable flexibility in the assembly and activation of the autophagy machinery, with significant implications for therapeutic interventions.

A PIKfyve modulator combined with an integrated stress response inhibitor to treat lysosomal storage diseases

Lysosomal degradation pathways coordinate the clearance of superfluous and damaged cellular components. Compromised lysosomal degradation is a hallmark of many degenerative diseases, including lysosomal storage diseases (LSDs), which are caused by loss-of-function mutations within both alleles of a lysosomal hydrolase, leading to lysosomal substrate accumulation. Gaucher's disease, characterized by <15% of normal glucocerebrosidase function, is the most common LSD and is a prominent risk factor for developing Parkinson's disease. Here, we show that either of two structurally distinct small molecules that modulate PIKfyve activity, identified in a high-throughput cellular lipid droplet clearance screen, can improve glucocerebrosidase function in Gaucher patient-derived fibroblasts through an MiT/TFE transcription factor that promotes lysosomal gene translation. An integrated stress response (ISR) antagonist used in combination with a PIKfyve modulator further improves cellular glucocerebrosidase activity, likely because ISR signaling appears to also be slightly activated by treatment by either small molecule at the higher doses employed. This strategy of combining a PIKfyve modulator with an ISR inhibitor improves mutant lysosomal hydrolase function in cellular models of additional LSD.

Targeted degradation of membrane and extracellular proteins with LYTACs.

Targeted protein degradation technology has gained substantial momentum over the past two decades as a revolutionary strategy for eliminating pathogenic proteins that are otherwise refractory to treatment. Among the various approaches developed to harness the body's innate protein homeostasis mechanisms for this purpose, lysosome targeting chimeras (LYTACs) that exploit the lysosomal degradation pathway by coupling the target proteins with lysosome-trafficking receptors represent the latest innovation. These chimeras are uniquely tailored to degrade proteins that are membrane-bound and extracellular, encompassing approximately 40% of all proteome. Several novel LYTAC formulas have been developed recently, providing valuable insights for the design and development of therapeutic degraders. This review delineates the recent progresses of LYTAC technology, its practical applications, and the factors that dictate target degradation efficiency. The potential and emerging trends of this technology are discussed as well. LYTAC technology offers a promising avenue for targeted protein degradation, potentially revolutionizing the therapeutic landscape for numerous diseases.

Functional OmpA of Salmonella Typhimurium provides protection from lysosomal degradation and inhibits autophagic processes in macrophages.

Our previous study showed that OmpA-deficient Salmonella Typhimurium (STM) failed to retain LAMP-1, quit Salmonella-containing vacuole (SCV) and escaped to the host cytosol. Here we show that the cytosolic population of STM ΔompA sequestered autophagic markers, syntaxin17 and LC3B in a sseL-dependent manner and initiated lysosomal fusion. Moreover, inhibition of autophagy using bafilomycinA1 restored its intracellular proliferation. Ectopic overexpression of OmpA in STM ΔsifA restored its vacuolar niche and increased interaction of LAMP-1, suggesting a sifA-independent role of OmpA in maintaining an intact SCV. The OmpA extracellular loops impaired the LAMP-1 recruitment to SCV and caused bacterial release into the cytosol of macrophages, but unlike STM ΔompA, they retained their outer membrane stability and didn't activate the lysosomal degradation pathway aiding in their intra-macrophage survival. Finally, OmpA extracellular loop mutations protected the cytosolic STM ΔsifA from the lysosomal surveillance, revealing a unique OmpA-dependent strategy of STM for its intracellular survival.

The journey of STING: Guiding immune signaling through membrane trafficking

Stimulator of Interferon Genes (STING) serves as a pivotal mediator in the innate immune signaling pathway, transducing signals from various DNA receptors and playing a crucial role in natural immune processes. During cellular quiescence, STING protein resides in the endoplasmic reticulum (ER), and its activation typically occurs through the cGAS-STING signaling pathway. Upon activation, STING protein is transported to the Golgi apparatus, thereby initiating downstream signaling cascades. Vesicular transport serves as the primary mechanism for STING protein trafficking between the ER and Golgi apparatus, with COPII mediating anterograde transport from the ER to Golgi apparatus, while COPI is responsible for retrograde transport. Numerous factors influence these transport processes, thereby exerting either promoting or inhibitory effects on STING protein expression. Upon reaching the Golgi apparatus, to prevent over-activation, STING protein is transported to post-Golgi compartments for degradation. In addition to the conventional lysosomal degradation pathway, ESCRT has also been identified as one of the degradation pathways for STING protein. This review summarizes the recent findings on the membrane trafficking pathways of STING, highlighting their contributions to the regulation of cytokine production, the activation of immune cells, and the coordination of immune signaling pathways.

SNX32 Regulates Sorting and Trafficking of Activated EGFR to the Lysosomal Degradation Pathway.

SNX32 is a member of the evolutionarily conserved Phox (PX) homology domain- and Bin/Amphiphysin/Rvs (BAR) domain-containing sorting nexin (SNX-BAR) family of proteins, which play important roles in sorting and membrane trafficking of endosomal cargoes. Although SNX32 shares the highest amino acid sequence homology with SNX6, and has been believed to function redundantly with SNX5 and SNX6 in retrieval of the cation-independent mannose-6-phosphate receptor (CI-MPR) from endosomes to the trans-Golgi network (TGN), its role(s) in intracellular protein trafficking remains largely unexplored. Here, we report that it functions in parallel with SNX1 in mediating epidermal growth factor (EGF)-stimulated postendocytic trafficking of the epidermal growth factor receptor (EGFR). Moreover, SNX32 interacts directly with EGFR, and recruits SNX5 to promote sorting of EGF-EGFR into multivesicular bodies (MVBs) for lysosomal degradation. Thus, SNX32 functions distinctively from other SNX-BAR proteins to mediate signaling-coupled endolysosomal trafficking of EGFR.

Targeted protein degradation combined with PET imaging reveals the role of host PD-L1 in determining anti-PD-1 therapy efficacy.

Immunohistochemical staining of programmed death-ligand 1 (PD-L1) in tumor biopsies acquired through invasive procedures is routinely employed in clinical practice to identify patients who are most likely to benefit from anti-programmed cell death protein 1 (PD-1) therapy. Nevertheless, PD-L1 expression is observed in various cellular subsets within tumors and their microenvironments, including tumor cells, dendritic cells, and macrophages. The impact of PD-L1 expression across these different cell types on the responsiveness to anti-PD-1 treatment is yet to be fully understood. We synthesized polymer-based lysosome-targeting chimeras (LYTACs) that incorporate both PD-L1-targeting motifs and liver cell-specific asialoglycoprotein receptor (ASGPR) recognition elements. Small-animal positron emission tomography (PET) imaging of PD-L1 expression was also conducted using a PD-L1-specific radiotracer 89Zr-αPD-L1/Fab. The PD-L1 LYTAC platform was capable of specifically degrading PD-L1 expressed on liver cancer cells through the lysosomal degradation pathway via ASGPR without impacting the PD-L1 expression on host cells. When coupled with whole-body PD-L1 PET imaging, our studies revealed that host cell PD-L1, rather than tumor cell PD-L1, is pivotal in the antitumor response to anti-PD-1 therapy in a mouse model of liver cancer. The LYTAC strategy, enhanced by PET imaging, has the potential to surmount the limitations of knockout mouse models and to provide a versatile approach for the selective degradation of target proteins in vivo. This could significantly aid in the investigation of the roles and mechanisms of protein functions associated with specific cell subsets in living subjects.

Hypoxia and oxidative stress impair autophagy and cell death mechanisms in trophoblast cells and reduce placental effciency in rodents

Introduction: Hypoxia and oxidative stress can activate autophagy, a lysosomal degradation pathway that maintains cellular homeostasis. Impairments in autophagy mechanisms have been observed in placentas from obstetric complications associated with placental hypoxia and oxidative stress, such as preeclampsia and intrauterine growth restriction. The objective of this study was to investigate the effects of hypoxia and oxidative stress on placental cell autophagy. We hypothesized that exposure to oxidative stress and hypoxia would alter the balance between cytotoxic and cytoprotective mechanisms in human trophoblast cells and rat placentas and would adversely affect placental effciency. Methods: We used an in vitro model incorporating human trophoblast cells (BeWo cells) exposed to an oxidative stressor, antimycin A (10, 100, 320 μM) or vehicle for 4 hours. Trophoblast cell death and autophagy mechanisms were assessed via flow cytometry and western blotting. Additionally, we used a rodent model of gestational sleep apnea, a pregnancy complication associated with placental hypoxia. Long Evans timed-pregnant dams were exposed to chronic intermittent hypoxia (CIH; n=6-8) or normoxia (NX; n=8-9) during their sleep cycle from gestational day (GD) 15 to 20 (term=21-23 days). Results: In trophoblast cells (n=5-9 independent experiments), antimycin A increased necrosis and LC3 A/B II/I ratio (autophagy marker) at 100 μM compared to vehicle (p≤0.015). At antimycin A 320 μM, necrosis remained elevated, while BAX (pro-apoptotic marker) and p62 (autophagosomal flux marker) were reduced compared to vehicle (p&lt;0.0001), and LC3 A/B II/I ratio returned to vehicle levels (p&gt;0.05 vs. vehicle). Placental weights from CIH exposed dams were greater (NX: 0.51±0.02 g vs. CIH: 0.60±0.03 g, p=0.015) and fetal to placental weight ratios (marker of placental effciency) were reduced compared to control pregnancies (NX: 5.25±0.13 vs. CIH: 4.43±0.14, p=0.0006) on GD20. Gestational CIH did not affect (p&gt;0.05) fetal weights (NX: 2.76±0.06 g vs. CIH: 2.61±0.06 g), crown to rump length (NX: 3.32±0.03 cm vs. CIH: 3.18±0.12 cm), abdominal girth (NX: 3.22±0.06 cm vs. CIH: 3.32±0.12 cm), or litter size (NX: 11.9±0.90 vs. CIH: 10.5±0.82). Conclusion: Oxidative stress alters the balance between cytotoxic and cytoprotective mechanisms in trophoblast cells, promoting cell necrosis. Although assessment of autophagy machinery and cell death in placentas from hypoxic pregnancies is ongoing, our results indicate that gestational CIH adversely affects placental effciency. NIH R01 HL146562, AHA 22PRE-900431, T32 AG020494, AHA 22POST-903250. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Phenotyping adult mice with inducible depletion of sequestosome-1 (p62) in endothelial cells

Macroautophagy (autophagy) maintains intracellular homeostasis by targeting damaged / dysregulated organelles for their transport to and degradation by the lysosome. Autophagy regulated gene 3 ( Atg3) enables autophagosome maturation which is required for the process of autophagy to occur. We reported that inducible depletion of Atg3 specifically in endothelial cells (ECs) impairs arterial function in the absence of metabolic disruptions (Cho et al., Cardiovasc Res, 2023). Sequestosome-1 (p62/SQSTM1) tethers proteins into the autophagic pathway for subsequent lysosomal degradation. The contribution from EC p62 to arterial and metabolic function is unknown and we addressed this. Adult male and female C57BL/6 mice with tamoxifen inducible depletion of p62 specifically in ECs ( p62EC−/−) were compared to littermate controls ( p62EC+/+). p62/18S mRNA expression was lower (p&lt;0.05) in ECs but not vascular smooth muscle cells (VSM) from p62EC−/− [n=6] vs. p62EC+/+ [n=9] mice, whereas Beclin-1/18S was similar in ECs and VSM from both groups. Neither body composition, glucose disposal nor insulin tolerance were impacted by EC specific p62 depletion. Vascular contractile responses to: (i) phenylephrine mediated α1-activation and (ii) potassium chloride evoked L-type Ca2+ channel opening; and relaxation responses to (iii) acetylcholine (endothelium-dependent) and (iv) sodium nitroprusside (endothelium-independent); were similar between groups in mesenteric resistance arteries (isometric myography) and middle cerebral arteries (isobaric myography). Further, intrinsic arterial stiffness was not different between p62EC−/− [n=6] and p62EC+/+ [n=9] mice i.e., neither the elastic modulus nor stress vs. strain curves generated using segments of thoracic aorta were altered. These findings indicate EC specific p62 depletion does not impact arterial function or the indexes of systemic metabolism we measured. Because p62 is upregulated during cellular stress, it is possible that a challenge (e.g., hypoxia, ischemia) might be required to unmask a protective role for intact EC p62 and studies are ongoing to test this. Supported by AHA23PRE1025910 (SM); Rural and Underserved Utah Training Experience T32 (CG), Pacific Islander Research Internship Program (LG), NIHR01HL149870-01A1 (SB) and NIHRO1HL141540 (JDS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Altered Plasma Membrane Lipid Composition in Hypertensive Neutrophils Impacts Epithelial Sodium Channel (ENaC) Endocytosis.

Biological membranes are composed of a lipid bilayer with embedded proteins, including ion channels like the epithelial sodium channel (ENaC), which are critical for sodium homeostasis and implicated in arterial hypertension (HTN). Changes in the lipid composition of the plasma membrane can significantly impact cellular processes related to physiological functions. We hypothesized that the observed overexpression of ENaC in neutrophils from HTN patients might result from alterations in the structuring domains within the plasma membrane, disrupting the endocytic processes responsible for ENaC retrieval. This study assessed the structural lipid composition of neutrophil plasma membranes from HTN patients along with the expression patterns of key elements regulating ENaC at the plasma membrane. Our findings suggest alterations in microdomain structure and SGK1 kinase activity, which could prolong ENaC presence on the plasma membrane. Additionally, we propose that the proteasomal and lysosomal degradation pathways are insufficient to diminish ENaC presence at the plasma membrane in HTN. These results highlight the importance of understanding ENaC retrieval mechanisms and suggest that targeting these mechanisms could provide insights for developing drugs to prevent and treat HTN.

Targeted Degradation of Cell‐Surface Proteins via Chaperone‐Mediated Autophagy by Using Peptide‐Conjugated Antibodies

AbstractCell‐surface proteins are important drug targets but historically have posed big challenges for the complete elimination of their functions. Herein, we report antibody–peptide conjugates (Ab‐CMAs) in which a peptide targeting chaperone‐mediated autophagy (CMA) was conjugated with commercially available monoclonal antibodies for specific cell‐surface protein degradation by taking advantage of lysosomal degradation pathways. Unique features of Ab‐CMAs, including cell‐surface receptor‐ and E3 ligase‐independent degradation, feasibility towards different cell‐surface proteins (e.g., epidermal growth factor receptor (EGFR), programmed cell death ligand 1 (PD‐L1), human epidermal growth factor receptor 2 (HER2)) by a simple change of the antibody, and successful tumor inhibition in vivo, make them attractive protein degraders for biomedical research and therapeutic applications. As the first example employing CMA to degrade proteins from the outside in, our findings may also shed new light on CMA, a degradation pathway typically targeting cytosolic proteins.

Targeted Degradation of Cell-Surface Proteins via Chaperone-Mediated Autophagy by Using Peptide-Conjugated Antibodies.

Cell-surface proteins are important drug targets but historically have posed big challenges for the complete elimination of their functions. Herein, we report antibody-peptide conjugates (Ab-CMAs) in which a peptide targeting chaperone-mediated autophagy (CMA) was conjugated with commercially available monoclonal antibodies for specific cell-surface protein degradation by taking advantage of lysosomal degradation pathways. Unique features of Ab-CMAs, including cell-surface receptor- and E3 ligase-independent degradation, feasibility towards different cell-surface proteins (e.g., epidermal growth factor receptor (EGFR), programmed cell death ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2)) by a simple change of the antibody, and successful tumor inhibition in vivo, make them attractive protein degraders for biomedical research and therapeutic applications. As the first example employing CMA to degrade proteins from the outside in, our findings may also shed new light on CMA, a degradation pathway typically targeting cytosolic proteins.

Degradation meets development: Implications in β-cell development and diabetes.

Pancreatic development is orchestrated by timely synthesis and degradation of stage-specific transcription factors (TFs). The transition from one stage to another stage is dependent on the precise expression of the developmentally relevant TFs. Persistent expression of particular TF would impede the exit from the progenitor stage to the matured cell type. Intracellular protein degradation-mediated protein turnover contributes to a major extent to the turnover of these TFs and thereby dictates the development of different tissues. Since even subtle changes in the crucial cellular pathways would dramatically impact pancreatic β-cell performance, it is generally acknowledged that the biological activity of these pathways is tightly regulated by protein synthesis and degradation process. Intracellular protein degradation is executed majorly by the ubiquitin proteasome system (UPS) and Lysosomal degradation pathway. As more than 90% of the TFs are targeted to proteasomal degradation, this review aims to examine the crucial role of UPS in normal pancreatic β-cell development and how dysfunction of these pathways manifests in metabolic syndromes such as diabetes. Such understanding would facilitate designing a faithful approach to obtain a therapeutic quality of β-cells from stem cells.

Bitter Taste Receptor T2R14 and Autophagy Flux in Gingival Epithelial Cells.

Macroautophagy (hereafter autophagy) is a lysosomal degradation pathway that functions in nutrient recycling and as a mechanism of innate immunity. Previously, we reported a novel host-bacteria interaction between cariogenic S. mutans and bitter taste receptor (T2R14) in gingival epithelial cells (GECs), leading to an innate immune response. Further, S. mutans might be using the host immune system to inhibit other Gram-positive bacteria, such as S. aureus. To determine whether these bacteria exploit the autophagic machinery of GEC, it is first necessary to evaluate the role of T2R14 in modulating autophagic flux. So far, the role of T2R14 in the regulation of autophagy is not well characterized. Therefore, in this study, for the first time, we report that T2R14 downregulates autophagy flux in GECs, and T2R14 knockout increases acidic vacuoles. However, the treatments of GEC WT with a T2R14 agonist and antagonist did not lead to a significant change in acidic vacuole formation. Transmission electron microscopy morphometric results also suggested an increased number of autophagic vesicles in T2R14-knockout GEC. Further, our results suggest that S. mutans competence stimulating peptide CSP-1 showed robust intracellular calcium release and this effect is both T2R14- and autophagy protein 7-dependent. In this study, we provide the first evidence that T2R14 modulates autophagy flux in GEC. The results of the current study could help in identifying the impact of T2R in regulation of the immuno-microenvironment of GEC and subsequently oral health.

14-3-3 proteins-a moonlight protein complex with therapeutic potential in neurological disorder: in-depth review with Alzheimer's disease.

Alzheimer's disease (AD) affects millions of people worldwide and is a gradually worsening neurodegenerative condition. The accumulation of abnormal proteins, such as tau and beta-amyloid, in the brain is a hallmark of AD pathology. 14-3-3 proteins have been implicated in AD pathology in several ways. One proposed mechanism is that 14-3-3 proteins interact with tau protein and modulate its phosphorylation, aggregation, and toxicity. Tau is a protein associated with microtubules, playing a role in maintaining the structural integrity of neuronal cytoskeleton. However, in the context of Alzheimer's disease (AD), an abnormal increase in its phosphorylation occurs. This leads to the aggregation of tau into neurofibrillary tangles, which is a distinctive feature of this condition. Studies have shown that 14-3-3 proteins can bind to phosphorylated tau and regulate its function and stability. In addition, 14-3-3 proteins have been shown to interact with beta-amyloid (Aβ), the primary component of amyloid plaques in AD. 14-3-3 proteins can regulate the clearance of Aβ through the lysosomal degradation pathway by interacting with the lysosomal membrane protein LAMP2A. Dysfunction of lysosomal degradation pathway is thought to contribute to the accumulation of Aβ in the brain and the progression of AD. Furthermore, 14-3-3 proteins have been found to be downregulated in the brains of AD patients, suggesting that their dysregulation may contribute to AD pathology. For example, decreased levels of 14-3-3 proteins in cerebrospinal fluid have been suggested as a biomarker for AD. Overall, these findings suggest that 14-3-3 proteins may play an important role in AD pathology and may represent a potential therapeutic target for the disease. However, further research is needed to fully understand the mechanisms underlying the involvement of 14-3-3 proteins in AD and to explore their potential as a therapeutic target.

Self-Assembly of Erlotinib-Platinum(II) Complexes for Epidermal Growth Factor Receptor-Targeted Photodynamic Therapy.

Due to cell mutation and self-adaptation, the application of clinical drugs with early epidermal growth factor receptor (EGFR)-targeted inhibitors is severely limited. To overcome this limitation, herein, the synthesis and in-depth biological evaluation of an erlotinib-platinum(II) complex as an EGFR-targeted anticancer agent is reported. The metal complex is able to self-assemble inside an aqueous solution and readily form nanostructures with strong photophysical properties. While being poorly toxic toward healthy cells and upon treatment in the dark, the compound was able to induce a cytotoxic effect in the very low micromolar range upon irradiation against EGFR overexpressing (drug resistant) human lung cancer cells as well as multicellular tumor spheroids. Mechanistic insights revealed that the compound was able to selectively degrade the EGFR using the lysosomal degradation pathway upon generation of singlet oxygen at the EGFR. We are confident that this work will open new avenues for the treatment of EGFR-overexpressing tumors.