Dictyostelium discoideum is a single-celled protist that undergoes multicellular development in response to nutrient deprivation. For close to a century, D. discoideum has been used as a model system for studying conserved cellular and developmental processes such as chemotaxis, cell adhesion, and cell differentiation. In the later decades of the 20th century, intensive research efforts examined the synthesis, trafficking, and activity of lysosomal enzymes in D. discoideum. Subsequent work has revealed that lysosomes are essential for all stages of the D. discoideum life cycle and the genome encodes dozens of homologs of human lysosomal enzymes, including those associated with lysosomal storage diseases. Additionally, protocols for examining the trafficking and activity of lysosomal enzymes in D. discoideum are well-established. Here, we provide a comprehensive up-to-date review that summarizes our current knowledge of lysosomal enzyme processing and trafficking in D. discoideum, with an eye towards re-establishing D. discoideum as a model eukaryote for studying the functions of conserved lysosomal enzymes and the pathways that regulate their trafficking.

Intramuscular adipose tissue is associated with an increased risk for the development of metabolic syndrome. A cellular model of adipogenesis in muscular tissues would be an invaluable tool for studying regulatory factors in this important process. Cellular stress can impact the homeostasis of various metabolic pathways including lipid metabolism. In this study, a porcine intramuscular preadipocyte cell line was established which displayed mature adipocyte attributes such as lipid accumulation and increased expression of adipogenic gene markers. Since it is well established that endoplasmic reticulum (ER) and Golgi stress impact adipogenesis, we sought to investigate the effects of ER/Golgi stress and an associated protein, CREB3, in this cell line model. We found that this novel model maintains robust adipogenic capabilities, and that ER stress can negatively affect adipogenic markers. Overall, these findings demonstrate the strength of the new cell model for studying adipogenesis, and highlight the impact of ER stress on lipid metabolism.

The chromatin remodeler SRCAP plays a critical role in depositing the histone variant H2A.Z, which is essential for transcriptional regulation, chromatin accessibility, and neurodevelopmental processes. Despite its known importance, the mechanisms by which SRCAP regulates H2A.Z dynamics during neuronal differentiation remain poorly understood. Here, we investigated the impact of Srcap knockdown on H2A.Z incorporation and transcriptional regulation in N2A cells. Chromatin immunoprecipitation (ChIP) revealed reduced H2A.Z occupancy at activity-dependent and neurodevelopmental genes upon Srcap knockdown, confirming Srcap's role in H2A.Z deposition. Interestingly, CBP recruitment and global histone H3 acetylation were unaffected by Srcap knockdown at steady-state conditions, suggesting an H2A.Z-specific function of Srcap. We also observed that retinoic acid-induced neuronal differentiation leads to dynamic changes in H2A.Z levels at developmental loci, which are disrupted in Srcap-deficient cells. Gene expression analysis revealed altered expression of neurodevelopmental genes in the absence of Srcap, correlating with reduced H2A.Z occupancy. Together, these findings demonstrate that Srcap is essential for regulating H2A.Z dynamics and gene expression during neuronal differentiation, offering new insights into its role in chromatin remodelling and its potential involvement in neurodevelopmental disorders.

Lactoferrin (Lf) is a multifunctional iron-binding glycoprotein, involved in a wide range of bioactivities, including immunomodulatory and antiviral activities. Lf in human milk and bovine Lf added to infant formula may provide some protection against viral infections. However, functions of Lfs from different sources may differ due to varying manufacturing processes and posttranslational modifications. Here, effects of Lfs (11 commercial bovine milk Lfs, 2 recombinant Lfs, and native human/bovine milk Lf) on cytokine responses to virus infection were examined by infecting human intestinal epithelial cells (Caco-2 cells) with rotavirus (naked) or normal human bronchial epithelial cells (BEAS-2B cells) with respiratory syncytial virus (RSV, enveloped) or SARS-CoV-2 spike protein 1. Effects of Lf on viral infection were evaluated by qRT-PCR analysis of transcripts of cytokines/chemokines (TNF-α, IL-1 β, IL-6, IL-8, IL-10, IFN-β, and CXCL10). Our results show that viral infection changes transcription of these cytokines and that Lfs significantly and variously influence immune responses to rotavirus, RSV, and SARS-CoV-2 in vitro. Thus, Lf may provide protection against virus infection by down-regulating pro‑inflammatory cytokine/chemokine responses. Recombinant bovine and human Lf show similar effects as bovine milk Lfs suggesting that different posttranslational modifications do not affect the antiviral activity on cytokine response.

Estrogen (E2) regulates the differentiation and proliferation of mammary progenitor cells by modulating the transcription of multiple genes. One of the genes that is downregulated by E2 is SOX2, a transcription factor associated with stem and progenitor cells that is overexpressed during breast tumourigenesis. To elucidate the mechanisms underlying E2-mediated SOX2 repression, we investigated epigenome and transcriptome changes following short- and long-term E2 exposure in breast cancer cells. We found that short-term E2 exposure reduces chromatin accessibility at the downstream SOX2 SRR134 enhancer, decreasing SOX2 expression. In contrast, long-term E2 exposure completely represses SOX2 transcription while maintaining accessibility at the SRR124-134 enhancer cluster, keeping it poised for reactivation. This repression was accompanied by widespread epigenome and transcriptome changes associated with commitment towards a more differentiated and less invasive luminal phenotype. Finally, we identified a role for the transcription factor NFIB in this process, suggesting it collaborates with the estrogen receptor to mediate SOX2 repression and genome-wide epigenome accessibility changes.

Chronic inflammation is a driving factor in diseases like obesity and type 2 diabetes. Enhanced cellular glucose metabolism may contribute to heightened immune activation. A human supplementation trial showed that the n-3 PUFA α-linolenic acid (ALA) reduced oxidative phosphorylation in monocytes. Our objective here is to assess the direct effects of ALA and docosahexaenoic acid (DHA) on glucose metabolism in a cell culture model and to explore possible molecular mechanisms. THP-1 monocytes were treated with 10-40 µmol/L of ALA or DHA and compared with vehicle and oleic acid controls. The Seahorse XFe24 and Oroboros Ok Oxygraph systems were used to approximate catabolic rates in the presence of glucose. Both ALA and DHA reduced oxidative phosphorylation. We identified pyruvate dehydrogenase kinase 4 (PDK4) as a possible mechanistic candidate explaining the effect of DHA. Additionally, both n-3 PUFAs reduced lipopolysaccharides-induced IL-1β production, while only DHA increased reactive oxygen species to a small but significant extent. Our data suggest that ALA and DHA trigger a re-wiring of bioenergetic pathways in monocytes, possibly via the upregulation of PDK4. Given the close relationship between cell metabolism and immune cell activation, this may represent a novel mechanism by which n-3 fatty acids modulate immune function and inflammation.

Doxorubicin is a chemotherapeutic drug for cancer that intercalates into nucleosome-free regions at promoters. Doxorubicin was reported to result in loss of histone H3 trimethylated lysine 4 (H3K4me3). To further explore doxorubicin's mechanism of action, we determined the genomic location of the binding sites of doxorubicin in leukemic cells. The effect of doxorubicin intercalation into the chromatin of leukemic cells on histone modifications was also determined. We show that doxorubicin binding sites were present in the nucleosome-free regions associated with regulatory regions (promoters, enhancers, and super-enhancers) and in the gene body (introns). Doxorubicin treatment did not alter the levels of H3K4me3 and many other histone modifications but significantly lowered H2B ubiquitinated at lysine 120 (H2BK120ub), an elongation-dependent modification. Lastly, we demonstrate that doxorubicin results in the degradation of the largest subunit (RPB1) of RNA polymerase II.

The paper aimed to reveal the impacts and the possible mechanism of action of lectin mannose-binding 2 protein (LMAN2) in HER2-positive breast cancer (BC). The expression, prognostic potential of LMAN2, and the correlation between LMAN2 and HEAT repeat containing 3 (HEATR3) in BC were analyzed in TCGA database. Intact, Mentha, and BioGrid databases predicted LMAN2-HEATR3 interactions. Reverse transcription-quantitative PCR and Western blot examined LMAN2 expression. Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine staining, wound healing, and transwell assays, respectively, detected the aggressive cellular biological behaviors including proliferation, migration, and invasion. Western blot analyzed the expression of matrix metalloproteinases, HEATR3, and protein kinase B (Akt)/extracellular signal-regulated kinase (ERK)/nuclear factor-kappaB (NF-κB) signaling-related proteins. Co-immunoprecipitation assay was used to prove the relationship of LMAN2 with HEATR3. Enzyme-linked immunosorbent assay detected inflammatory cytokine levels. LMAN2 was overexpressed in HER2-positive BC tissues and cells and indicated unfavorable prognosis of BC patients. LMAN2 knockdown suppressed HER2-positive BC cell proliferation, migration, and invasion. LMAN2 interacted with and had a positive correlation with HEATR3. HEATR3 up-regulation reversed the repressive role of LMAN2 interference in the progression of HER2-positive BC, Akt/ERK/NF-κB signaling, and inflammatory response. Altogether, LMAN2 silencing might exert anti-tumor and anti-inflammatory properties and inactivate Akt/ERK/NF-κB signaling in HER2-positive BC via binding to HEATR3.

Idiopathic pulmonary fibrosis (IPF) is a progressive and irreversible lung disease with high mortality and limited treatment options. While single-dose bleomycin-induced models are commonly used to investigate the pathogenesis of IPF, they fail to adequately replicate the complex pathological features in human patients, thereby hindering comprehensive investigations. Previous studies utilizing repetitive bleomycin injections have demonstrated a closer resemblance to human IPF pathology; however, the time- and resource-intensive nature of this approach presents significant drawbacks. Here, we propose a novel methodology involving twice-repeated oropharyngeal administration of bleomycin in mice, which closely mirrors the pathological manifestations observed in IPF patients. This model exhibited the honeycomb-like cyst formation, fibroblastic foci, bronchiolization of alveolar epithelium, emergence of metaplastic alveolar KRT5 basal cells, and sustainability of these fibrotic phenotypes, thereby providing a robust model for IPF. Our findings establish a more efficient and translatable preclinical platform for investigating IPF pathogenesis and exploring potential therapeutic strategies.

Pediatric infections account for approximately one-third of all deaths in children under 5 years globally. Lactoferrin (LF) supplementation has the potential to reduce infection-related morbidity due to its antimicrobial, anti-inflammatory, and immunoregulatory properties. We conducted a systematic review and meta-analysis of oral LF supplementation randomized controlled trials in population under 18 years old. The primary outcomes were infection-associated outcomes: late onset sepsis (LOS), diarrhea, and upper respiratory infections (URIs). We also analyzed mortality among LOS studies. Of 1594 citations identified, 25 studies met eligibility criteria, including 10 studies of LOS, 14 of diarrhea, and 8 of URI. LF supplementation was associated with fewer patients with culture-proven or probable neonatal LOS compared to placebo (odds ratio (OR): 0.60; 95% confidence interval (CI): 0.42-0.86), with fewer patients with diarrhea compared to placebo in children (OR: 0.56; 95% CI: 0.41-0.75), and no significant fewer patients with URI (OR: 0.61; 95% CI: 0.27-1.40). Before LF can be used as a public health intervention, it is necessary to refine some aspects of the design of future trials. Ideally these trials should be conducted in countries with the highest burden of infections, where the potential benefit is expected to have the largest impact.

WD repeat domain 4 (WDR4) has been reported to promote tumor metastasis in various cancers. However, its precise function in colorectal cancer (CRC) has not been reported yet. Herein, the expression pattern of WDR4 in CRC was determined by analyzing Gene Expression Omnibus datasets (GSE110225, GSE127069, GSE156355, and GSE184093) and GEPIA online dataset. In vitro and in vivo experiments, including CCK-8, colony formation, flow cytometry, wound healing, transwell assays, and xenograft mouse models, were used to investigate the role of WDR4 in CRC. Firstly, data from Kaplan-Meier database showed that high expression of WDR4 was associated with the poor prognosis of CRC patients. Then, upregulation of WDR4 was confirmed in clinical CRC tissues. In vitro functional experiments suggested that overexpression of WDR4 promoted cell proliferation, migration, and invasion, while knockdown of WDR4 has the opposite effects. Also, the oncogenic role of WDR4 was also verified in in vivo experiments. CO-IP-LC/MS analysis uncovered that glycogen synthase kinase 3β (GSK3β) is the central protein that binds to WDR4. Mechanistically, WDR4 activated the β-catenin pathway by promoting GSK3β phosphorylation. This study demonstrates that WDR4 promotes CRC progression through activating GSK3β/β-catenin pathway, indicating that WDR4 might be a potential therapeutic target for CRC treatment.

Surface receptors in Gram-negative bacteria that bind and extract iron from the host glycoproteins transferrin (Tf) or lactoferrin (Lf) was discovered 35 years ago in pathogenic species and subsequently was discovered in other pathogens of humans and food production animals. These bacterial species reside exclusively on the mucosal surfaces of the respiratory or genitourinary tract of their mammalian host and rely on their host specific Tf and Lf receptors to acquire iron for survival. Since the specificity of the bacterial Tf receptors was shown to be due to selective pressures on the host Tf, their presence in bacteria that reside in both mammals and birds indicates that they arose over 320 million years ago. Once Lf arose in mammals due to a gene duplication event, Lf receptors subsequently arose from Tf receptors. The focus on pathogens for discovery of these receptors has led to a limited understanding of how prevalent the Tf and Lf receptors are in commensal species and raises the question whether they are present in additional bacterial lineages. Since the Lf receptor provides a secondary iron acquisition system plus can provide protection from cationic peptides its presence varies in bacterial lineages.

Methyl CpG binding protein 2 (MeCP2) is a chromatin-associated protein that remains enigmatic despite more than 30 years of research, primarily due to the ever-growing list of its molecular functions, and, consequently, its related pathologies. Loss of function mutations cause the neurodevelopmental disorder Rett syndrome (RTT); in addition, dysregulation of MeCP2 expression and/ or function are involved in numerous other pathologies, but the mechanisms of MeCP2 regulation are unclear. Advancing technologies and burgeoning mechanistic theories assist our understanding of the complexity of MeCP2 but may inadvertently cloud it if not rigorously tested. Here, rather than focus on RTT, we examine relatively underexplored aspects of MeCP2, such as its dosage homeostasis at the gene and protein levels, its controversial participation in phase separation, and its overlooked role in depression and oxidative stress. All these factors may be essential to understanding the full scope of MeCP2 function in healthy and diseased states, but are relatively infrequently studied and require further criticism. The aim of this review is to discuss the esoteric facets of MeCP2 at the molecular and pathological levels and to consider to what extent they may be necessary for general MeCP2 function.