Evaluating the capability of soybean peptides as calcium ion carriers: a study through sequence analysis and molecular dynamics simulations.

Calcium homeostasis imbalance in the body can lead to a variety of chronic diseases. Supplement efficiency is essential. Peptide calcium chelate, a fourth-generation calcium supplement, offers easy absorption and minimal side effects. Its effectiveness relies on peptide's calcium binding capacity. However, research on amino acid sequences in peptides with high calcium binding capacity (HCBC) is limited, affecting the efficient identification of such peptides. This study used soybean peptides (SP), separated and purified by gel chromatography, to obtain HCBC peptide (137.45 µg mg-1) and normal peptide (≤95.78 µg mg-1). Mass spectrometry identified the sequences of these peptides, and an analysis of the positional distribution of characteristic amino acids followed. Two HCBC peptides with sequences GGDLVS (271.55 µg mg-1) and YEGVIL (272.54 µg mg-1) were discovered. Molecular dynamics showed that when either aspartic acid is located near the N-terminal's middle, or glutamic acid is near the end, or in cases of continuous Asp or Glu, the binding speed, probability, and strength between the peptide and calcium ions are superior compared to those at other locations. The study's goal was to clarify how the positions of characteristic amino acids in peptides affect calcium binding, aiding in developing peptide calcium chelates as a novel calcium supplement.

Fluorine-Functionalized Covalent Organic Framework Superhydrophobic Modified Melamine Sponge for Efficient oil-water Separation.

Hydrophobic sponges have attracted significant interest in oil spills and water-oil separation as potential absorption materials due to their desirable absorptivity, selectivity, and elasticity. In this paper, a hydrophilic melamine sponge (MS) is transferred into a superhydrophobic sponge via polydimethylsiloxane (PDMS) modification followed by in situ growth of fluorine-functionalized covalent organic framework (denoted as TFA-COF) nanoparticles. Therefore, the PDMS@TFA-COF@MS sponge was successfully prepared for efficient oil-water separation. The resultant PDMS@TFA-COF@MS exhibits superhydrophobic properties with a water contact angle of 156.7°. The superhydrophobic sponge has selectivity adsorption for different organic solvents and oils from water as well as oil-water separation efficiency (96% after 30 cycles) and oil absorption capacity (12 646% after 30 cycles). Meanwhile, the PDMS@TFA-COF@MS sponge exhibits strong thermal stability and flame retardancy in addition to having exceptional resistance to chemical corrosion in acidic, alkaline, and salt solutions. Moreover, the surfactant-stabilized oil-in-water emulsion could be efficiently separated by the sponge. Therefore, the prepared superhydrophobic PDMS@TFA-COF@MS sponge demonstrates possible uses for long-life oil-water separation applications.

A core-shell structured AuNPs@ZnCo-MOF SERS substrate for sensitive and selective detection of thiram.

Surface-enhanced Raman scattering (SERS) enables pesticide residue monitoring to become facile and efficient. In this study, a core-shell structured gold nanoparticles@ZnCo metal-organic framework (AuNPs@ZnCo-MOF) SERS substrate was designed and successfully synthesized for efficient and selective detection of thiram. The bimetallic ZnCo-MOF shell can not only enrich the targeted molecules in the electromagnetic field because of its excellent absorptive capacity, but also act as a stabilized matrix for protecting the AuNPs from aggregation. The AuNPs@ZnCo-MOFs exhibited a high enhancement factor (EF) of 3.51 × 106 and a low detection limit of 1 × 10-7 mol L-1. Besides, the substrate material showed exceptional stability for up to 28 days at room temperature. The AuNPs@ZnCo-MOFs were used to detect thiram which displayed wide linearity (1 × 10-7 to 1 × 10-4 mol L-1) and high recoveries (83.45-99.61%). Moreover, the AuNPs@ZnCo-MOF SERS substrate exhibited excellent anti-interference ability and size selectivity for the target molecules. These indicate that the AuNPs@ZnCo-MOF substrate has great potential for the detection of thiram residues in practical applications.

Modulation of the vitamin D/vitamin D receptor system in osteoporosis pathogenesis: insights and therapeutic approaches.

Osteoporosis is a prevalent bone disorder characterized by low bone mineral density (BMD) and deteriorated bone microarchitecture, leading to an increased risk of fractures. Vitamin D (VD), an essential nutrient for skeletal health, plays a vital role in maintaining bone homeostasis. The biological effects of VD are primarily mediated through the vitamin D receptor (VDR), a nuclear receptor that regulates the transcription of target genes involved in calcium and phosphate metabolism, bone mineralization, and bone remodeling. In this review article, we conduct a thorough literature search of the PubMed and EMBASE databases, spanning from January 2000 to September 2023. Utilizing the keywords "vitamin D," "vitamin D receptor," "osteoporosis," and "therapy," we aim to provide an exhaustive overview of the role of the VD/VDR system in osteoporosis pathogenesis, highlighting the most recent findings in this field. We explore the molecular mechanisms underlying VDR's effects on bone cells, including osteoblasts and osteoclasts, and discuss the impact of VDR polymorphisms on BMD and fracture risk. Additionally, we examine the interplay between VDR and other factors, such as hormonal regulation, genetic variants, and epigenetic modifications, that contribute to osteoporosis susceptibility. The therapeutic implications of targeting the VDR pathway for osteoporosis management are also discussed. By bringing together these diverse aspects, this review enhances our understanding of the VD/VDR system's critical role in the pathogenesis of osteoporosis and highlights its significance as a potential therapeutic target.

The putative maintaining mechanism of gut bacterial ecosystem in giant pandas and its potential application in conservation.

Animals living in captivity and the wild show differences in the internal structure of their gut microbiomes. Here, we performed a meta-analysis of the microbial data of about 494 fecal samples obtained from giant pandas (captive and wild giant pandas). Our results show that the modular structures and topological features of the captive giant panda gut microbiome differ from those of the wild populations. The co-occurrence network of wild giant pandas also contained more nodes and edges, indicating a higher complexity and stability compared to that of captive giant pandas. Keystone species analysis revealed the differences between geographically different wild populations, indicating the potential effect of geography on the internal modular structure. When combining all the giant panda samples for module analysis, we found that the abundant taxa (e.g., belonged to Flavobacterium, Herbaspirillum, and Escherichia-Shigella) usually acted as module hubs to stabilize the modular structure, while the rare taxa usually acted as connectors of different modules. We conclude that abundant and rare taxa play different roles in the gut bacterial ecosystem. The conservation of some key bacterial species is essential for promoting the development of the gut microbiome in pandas. The living environment of the giant pandas can influence the internal structure, topological features, and strength of interrelationships in the gut microbiome. This study provides new insights into the conservation and management of giant panda populations.

CRISPR-Cas12a coupled with universal gold nanoparticle strand-displacement probe for rapid and sensitive visual SARS-CoV-2 detection.

Point of care (POC) diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are particularly significant for preventing transmission of coronavirus disease 2019 (COVID-19) by any user at any given time and place. CRISPR/Cas-assisted SARS-CoV-2 assays are viewed as supplemental to RT-PCR due to simple operation, convenient use and low cost. However, most current CRISPR molecular diagnostics based on fluorescence measurement increased the difficulty of POC test with need of the additional light sources. Some instrument-free visual detection with the naked eye has limitations in probe universality. Herein, we developed a universal, rapid, sensitive and specific SARS-CoV-2 POC test that combines the outstanding DNase activity of Cas12a with universal AuNPs strand-displacement probe. The oligo trigger, which is the switch the AuNPs of the strand-displacement probe, is declined as a result of Cas12a recognition and digestion. The amount of released AuNPs produced color change which can be visual with the naked eye and assessed by UV-Vis spectrometer for quantitative detection. Furthermore, a low-cost hand warmer is used as an incubator for the visual assay, enabling an instrument-free, visual SARS-CoV-2 detection within 20 min. A real coronavirus GX/P2V instead of SARS-CoV-2 were chosen for practical application validation. After rapid virus RNA extraction and RT-PCR amplification, a minimum of 2.7 × 102 copies/mL was obtained successfully. The modular design can be applied to many nucleic acid detection applications, such as viruses, bacteria, species, etc., by simply modifying the crRNA, showing great potential in POC diagnosis.

Food provisioning results in functional, but not compositional, convergence of the gut microbiomes of two wild Rhinopithecus species: Evidence of functional redundancy in the gut microbiome.

The consumption of similar diets has led to the convergence of gut microbial compositions and functions across phylogenetically distinct animals. However, given the functional redundancy in gut microbiomes, it remains unclear whether synchrony occurs in their functions only and not in their composition, even within phylogenetically close animals consuming a similar diet. In this study, we collected fresh fecal samples from a Rhinopithecus roxellana population in April 2021 (before food provisioning) and June and December 2021 (after food provisioning) and used high-throughput sequencing methods (full-length 16S rRNA gene sequencing and metagenomes) to investigate changes in the gut microbiome due to food provisioning. Combining the results from our previous studies on a wild Rhinopithecus bieti population, we found that the artificial food provisions (e.g., apples, carrots, and peanuts) affected the gut microbiome, and synchrony occurred only in its functions and antibiotic resistance gene community in both Rhinopithecus species, reflecting its ecological functional redundancy. Given the current findings (e.g., depletion in probiotic microbes, dysbiosis in the gut microbial community, and changes in the antibiotic resistance gene profile), anthropogenic disturbances (e.g., food provisioning) would have potential negative effects on host health. Therefore, human activity in animal conservation should be rethought from the standpoint of gut microbial diversity.

Systematically investigating the fluorescent signal readout of CRISPR-Cas12a for highly sensitive SARS-CoV-2 detection.

The CRISPR/Cas system is widely used for molecular diagnostics after the discovery of trans-cleavage activity, especially now with the COVID-19 outbreak. However, the majority of contemporary trans-cleavage activity-based CRISPR/Cas biosensors exploited standard single-strand DNA (ssDNA) reporters, which were based on the FRET principle from pioneering research. An in-depth comparison and understanding of various fluorescent readout types are essential to facilitate the outstanding analytical performance of CRISPR probes. We investigated various types of fluorescent reporters of Cas12a comprehensively. Results show that trans-cleavage of Cas12a is not limited to ssDNA and dsDNA reporters, but can be extended to molecular beacons (MB). And MB reporters can achieve superior analytical performance compared with ssDNA and ds DNA reporters at the same conditions. Accordingly, we developed a highly-sensitive SARS-CoV-2 detection with the sensitivity as low as 100 fM were successfully achieved without amplification strategy. The model target of ORF1a could robustly identify the current widespread emerging SARS-CoV-2 variants. A real coronavirus GX/P2V instead of SARS-CoV-2 were chosen for practical application validation. And a minimum of 27 copies/mL was achieved successfully. This inspiration can also be applied to other Cas proteins with trans-cleavage activity, which provides new perspectives for simple, highly-sensitive and universal molecular diagnosis in various applications.

Biological Properties and Clinical Significance of Lipoprotein-Associated Phospholipase A2 in Ischemic Stroke.

Ischemic stroke, which occurs following blockage of the blood supply to the brain, is a leading cause of death worldwide. Its main cause is atherosclerosis, a disease of the arteries characterized by the deposition of plaques of fatty material on the inner artery walls. Multiple proteins involved in the inflammation response have been identified as diagnosing biomarkers of ischemic stroke. One of these is lipoprotein-associated phospholipase A2 (Lp-PLA2), an enzyme that can hydrolyze circulating oxidized phospholipids, generating proinflammatory lysophosphatidylcholine and promoting the development of atherosclerosis. In the last two decades, a number of studies have revealed that both the concentration and the activity of Lp-PLA2 are independent biomarkers of ischemic stroke. The US Food and Drug Administration (FDA) has approved two tests to determine Lp-PLA2 mass and activity for predicting stroke. In this review, we summarize the biological properties of Lp-PLA2, the detection sensitivity and limitations of Lp-PLA2 measurement, the clinical significance and association of Lp-PLA2 in ischemic stroke, and the prospects of therapeutic inhibition of Lp-PLA2 as an intervention and treatment.

Fluorescence Signal-Readout of CRISPR/Cas Biosensors for Nucleic Acid Detection.

The CRISPR/Cas system is now being used extensively in nucleic acid detection applications, particularly after the trans-cleavage activity of several Cas effectors was found. A CRISPR/Cas system combined with multiple signal-readout techniques has been developed for various molecular diagnostics applications. Fluorescence is now a widely utilized dominant read-out technique in CRISPR biosensors. An in-depth understanding of various fluorescence readout types and variables affecting the fluorescence signals can facilitate better experimental designs to effectively improve the analytical performance. There are the following two commonly used types of CRISPR/Cas detection modes: the first is based on binding activity, such as Cas9 and dCas9; the second is based on cleavage activity, such as Cas12a, Cas12b, Cas13, and Cas14. In this review, fluorescence signal-readout strategies from the last 5 years based on the binding activity and cleavage activity of the CRISPR/Cas system with fundamentals and examples are fully discussed. A detailed comparison of the available fluorescent reporter sequences and design principles is summarized. Current challenges and further applications of CRISPR-based detection methods will be discussed according to the most recent developments.

Long-lasting beneficial effects of maternal intake of sulforaphane glucosinolate on gut microbiota in adult offspring.

Mounting evidence suggests the impact of maternal diet on the health of offspring. We reported that maternal diet of sulforaphane glucosinolate (SGS) could prevent behavioral abnormalities in offspring after maternal immune activation. The present study was designed to investigate whether the dietary intake of SGS during pregnancy and lactation influences the composition of gut microbiota in the offspring. The dietary intake of SGS during pregnancy and lactation caused significant changes in the α-diversity and ß-diversity of gut microbiota in 3-week-old offspring (SGS-3W group) and 10-week-old offspring (SGS-10W group). The LEfSe algorithm identified several microbes as important phylotypes in the SGS-3W or SGS-10W groups. Predictive functional metagenomes showed that the maternal intake of SGS caused several KEGG pathways alterations with respect to the genetic information processing and metabolism. Furthermore, the plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the SGS-10W group after the injection of lipopolysaccharide (LPS: 0.5 mg/kg) were significantly lower than those of the CON-10W group. It is noteworthy that there were positive correlations between the relative abundance of the genus Blautia and IL-6 (or TNF-α) in adult offspring. Moreover, there were sex differences of gut microbiota composition in offspring. In conclusion, these data suggest that the dietary intake of SGS during pregnancy and lactation might produce long-lasting beneficial effects in adult offspring through the persistent modulation of gut microbiota. It is likely that the modulation of gut microbiota by maternal nutrition may confer resilience versus vulnerability to stress-related psychiatric disorders in the offspring.

Research Progress of the Gut Microbiome in Hybrid Fish.

Fish, including hybrid species, are essential components of aquaculture, and the gut microbiome plays a vital role in fish growth, behavior, digestion, and immune health. The gut microbiome can be affected by various internal and/or external factors, such as host development, diet, and environment. We reviewed the effects of diet and dietary supplements on intestinal microorganisms in hybrid fish and the difference in the gut microbiome between the hybrid and their hybrids that originate. Then, we summarized the role of the gut microbiome in the speciation and ecological invasion of hybrid fish. Finally, we discussed possible future studies on the gut microbiome in hybrid fish, including the potential interaction with environmental microbiomes, the effects of the gut microbiome on population expansion, and fish conservation and management.

Functional convergence of Yunnan snub-nosed monkey and bamboo-eating panda gut microbiomes revealing the driving by dietary flexibility on mammal gut microbiome.

The gut microbiomes of non-human primates have received a great deal of attention due to their close relationship to humans. In recent years, these studies have mainly focused on the gut microbiome of wild primates, which will be helpful to understanding the evolution of primates and their gut microbiomes (e.g., gut microbiome plasticity and diet flexibility). However, there is still a lack of basic information on the gut microbiomes from wild populations. Here, we investigated the gut microbial composition (16S rRNA gene) and function (metagenome and metagenome-assembled genomes (MAGs)) of Yunnan snub-nosed monkey populations in Weixi County, Yunnan Province, China, that had diets either completely based on wild-foraging or were regularly supplemented with human provisioned food. We found a significant difference in the gut microbiome between these two populations: the gut microbiome of the wild-foraging (no food provision) population was enriched genes involved in the detoxification of bamboo cyanide (high proportion of bamboo shoot intake) and chitin (from insect diet) digestion, while the gut microbiome of the food provisioned (e.g., fruits) wild populations were enriched genes involved in carbohydrate metabolism. Moreover, the gut microbiome of the wild-foraging population shared a putatively functional convergence with the gut microbiome of wild bamboo-eating pandas: such as microbes and genes involved in the cyanide detoxification. Therefore, the gut microbiome of the Yunnan snub-nosed monkey displayed the potential plasticity in response to diet flexibility. Long-term food-provisioning of the wild population has led to dramatic changes in gut microbial composition, function, and even antibiotic resistance. The antibiotic resistance profile for the wild Yunnan snub-nosed monkey population could be considered the baseline and an important piece of information for conservation.

Understanding Responses of Soil Microbiome to the Nitrogen and Phosphorus Addition in Metasequoia glyptostroboides Plantations of Different Ages.

Nitrogen (N) and phosphorus (P) have significant effects on soil microbial community diversity, composition, and function. Also, trees of different life stages have different fertilization requirements. In this study, we designed three N additions and three P levels (5 years of experimental treatment) at two Metasequoia glyptostroboides plantations of different ages (young, 6 years old; middle mature, 24 years old) to understand how different addition levels of N and P affect the soil microbiome. Here, the N fertilization of M. glyptostroboides plantation land (5 years of experimental treatment) significantly enriched microbes (e.g., Lysobacter, Luteimonas, and Rhodanobacter) involved in nitrification, denitrification, and P-starvation response regulation, which might further lead to the decreasing in alpha diversity (especially in 6YMP soil). The P addition could impact the genes involved in inorganic P-solubilization and organic P-mineralization by increasing soil AP and TP. Moreover, the functional differences in the soil microbiomes were identified between the 6YMP and 24YMP soil. This study provides valuable information that improves our understanding on the effects of N and P input on the belowground soil microbial community and functional characteristics in plantations of different stand ages.

Invasion and defense of the basic social unit in a nonhuman primate society leads to sexual differences in the gut microbiome.

Multilevel society is one of the most complex social systems in natural ecosystems and is a typical feature among some primates. Given the potential connection between social behavior and gut microbiome composition, the multilevel social system could affect the primate gut microbiome. Here, based on long-term observation (e.g. social unit dynamics, transfer, and behavior), we investigated this potential integrating 16S rRNA gene amplicon sequencing and behavior data in Yunnan snub-nosed monkeys (Rhinopithecus bieti), which possess a multilevel social group based on one male units (OMUs, each unit with several breeding females and their offspring) and all-male unit (AMU, several bachelor males residing together). We found that the mean unweighted Unifrac distance between adult males from different OMUs was significantly lower than that between adult females from different OMUs (paired Wilcoxon test, P = 0.007). There was no significant difference in the mean unweighted Unifrac distance between females within the same OMU or between females from different OMUs. These findings indicated the potential connection between the defense and invasion of social units and the gut microbiome community in wild Yunnan snub-nosed monkeys. We speculated that the resident males of OMUs displaying a significantly higher similarity in the gut microbial community than that of adult females in separate OMUs might be associated with the sexual differences in their interactions and from previously having cohabitated together in the AMU. Therefore, this study suggested that multilevel societies might have an effect on the gut microbial community in this wild nonhuman primate species.

Fly-over phylogeny across invertebrate to vertebrate: The giant panda and insects share a highly similar gut microbiota.

Many studies highlight that host phylogeny and diet are the two main factors influencing the animal gut microbiota. However, the internal mechanisms driving the evolution of animal gut microbiota may be more complex and complicated than we previously realized. Here, based on a large-scale meta-analysis of animal gut microbiota (16 s RNA gene data from approximately 1,800 samples; 108 metagenomes) across a wide taxonomic range of hosts, from invertebrate to vertebrate, we found high similarity in the gut microbial community (high proportion of Gammaproteobacteria (Pseudomonas)) of invertebrate insects and vertebrate bamboo-eating pandas (giant panda and red panda), which might be associated their plant-eating behavior and the presence of oxygen in the intestinal tract. A Pseudomonas strain-level analysis using 108 metagenomes further revealed that the response to either host niches or selection by the host might further lead to host-specific strains (or sub-strains) among the different hosts congruent with their evolutionary history. In this study, we uncovered new insights into the current understanding of the evolution of animals and their gut microbiota.

Host Bias in Diet-Source Microbiome Transmission in Wild Cohabitating Herbivores: New Knowledge for the Evolution of Herbivory and Plant Defense.

It is commonly understood that dietary nutrition will influence the composition and function of the animal gut microbiome. However, the transmission of organisms from the diet-source microbiome to the animal gut microbiome in the natural environment remains poorly understood, and elucidating this process may help in understanding the evolution of herbivores and plant defenses. Here, we investigated diet-source microbiome transmission across a range of herbivores (insects and mammals) living in both captive and wild environments. We discovered a host bias among cohabitating herbivores (leaf-eating insects and deer), where a significant portion of the herbivorous insect gut microbiome may originate from the diet, while in deer, only a tiny fraction of the gut microbiome is of dietary origin. We speculated that the putative difference in the oxygenation level in the host digestion systems would lead to these host biases in plant-source (diet) microbiome transmission due to the oxygenation living condition of the dietary plant's symbiotic microbiome. IMPORTANCE We discovered a host bias among cohabitating herbivores (leaf-eating insects and deer), where a significant portion of the herbivorous insect gut microbiome may originate from the diet, while in deer, only a tiny fraction of the gut microbiome is of dietary origin. We speculated that the putative difference in the oxygenation level in the host digestion systems would lead to these host biases in plant-source (diet) microbiome transmission due to the oxygenation living condition of the dietary plant's symbiotic microbiome. This study shed new light on the coevolution of herbivory and plant defense.

Social behavior of musk deer during the mating season potentially influences the diversity of their gut microbiome.

An increasing body of research has revealed that social behavior shapes the animal gut microbiome community and leads to the similarity among the same social group. However, some additional factors (e.g., diet and habitat within each social group) may also contribute to this similarity within the social group and dissimilarity between social groups. Here, we investigated the potential correlation between social behavior and the gut microbiome community in 179 musk deer from four breeding regions in the Maerkang Captive Center, Sichuan. The dominant gut microbiome phyla in the musk deer in this study were Firmicutes, Bacteroidetes, and Proteobacteria. We found significant effects on the alpha and beta diversity of the gut microbiome due to the breeding regions. The similarity within breeding regions was higher than that between the breeding regions. Due to their solitary lifestyle, captive musk deer are raised in single cages with no direct social contact most of the time. Deer in all of the breeding regions have the same diet and similar living conditions. However, during each mating season from November to January, in each region, one adult male and about six adult females will be put together into a large cage. Social behavior happens during cohabitation, including mating behavior, grooming within the same sex or between different sexes, and other social contact. Therefore, we speculated that high similarity within the breeding region might be associated with the social behavior during the mating season. This was a simple and straightforward example of the relationship between animal social behavior and the gut microbiome.

Circ_0006528 Contributes to Paclitaxel Resistance of Breast Cancer Cells by Regulating miR-1299/CDK8 Axis.

BACKGROUND: Circular RNAs (circRNAs) have been reported to be involved in regulating the development of breast cancer. Paclitaxel (PTX) can be used for the chemotherapy of breast cancer. The study aimed to explore the role and mechanism of circ_0006528 in PTX-resistant breast cancer progression. METHODS: The levels of circ_0006528, microRNA-1299 (miR-1299) and cyclin-dependent kinase 8 (CDK8) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). RNase R treatment was used to confirm that the circ_0006528 was a circular RNA. PTX resistance and cell proliferation were determined by Cell counting kit-8 (CCK-8) assay. Cell apoptosis, migration and invasion were analyzed by flow cytometry and Transwell assays, respectively. The levels of all proteins were examined by Western blot. The interaction between circ_0006528 and miR-1299 or CDK8 was predicted by online database confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft mice model was constructed to reveal the role of circ_0006528 on tumor growth in vivo. RESULTS: Circ_0006528 was significantly up-regulated and miR-1299 was down-regulated in PTX-resistant breast cancer tissues and cells compared with control groups. CDK8 protein expression was dramatically upregulated in PTX-resistant breast cancer tissues and cells as compared to control groups. Loss-of-function experiments revealed that circ_0006528 knockdown decreased IC50 value of PTX and restrained proliferation, migration, invasion and autophagy, whereas induced apoptosis of PTX-resistant breast cancer cells in vitro. The inhibitory effects of sh-circ_0006528 on the progression of PTX-resistant breast cancer cells were reversed by decreasing miR-1299 or increasing CDK8 expression. Furthermore, circ_0006528 could modulate CDK8 expression by sponging miR-1299. Circ_0006528 silencing impeded the growth of PTX-resistant tumors by regulating miR-1299/CDK8 axis in vivo. CONCLUSION: Circ_0006528 partially contributed to PTX resistance of breast cancer cells through up-regulating CDK8 expression by sponging miR-1299.

Hyperandrogenism and insulin resistance modulate gravid uterine and placental ferroptosis in PCOS-like rats.

Women with polycystic ovary syndrome (PCOS) have hyperandrogenism and insulin resistance and a high risk of miscarriage during pregnancy. Similarly, in rats, maternal exposure to 5α-dihydrotestosterone (DHT) and insulin from gestational day 7.5 to 13.5 leads to hyperandrogenism and insulin resistance and subsequently increased fetal loss. A variety of hormonal and metabolic stimuli are able to trigger different types of regulated cell death under physiological and pathological conditions. These include ferroptosis, apoptosis and necroptosis. We hypothesized that, in rats, maternal hyperandrogenism and insulin-resistance-induced fetal loss is mediated, at least in part, by changes in the ferroptosis, apoptosis and necroptosis pathways in the gravid uterus and placenta. Compared with controls, we found that co-exposure to DHT and insulin led to decreased levels of glutathione peroxidase 4 (GPX4) and glutathione, increased glutathione + glutathione disulfide and malondialdehyde, aberrant expression of ferroptosis-associated genes (Acsl4, Tfrc, Slc7a11, and Gclc), increased iron deposition and activated ERK/p38/JNK phosphorylation in the gravid uterus. In addition, we observed shrunken mitochondria with electron-dense cristae, which are key features of ferroptosis-related mitochondrial morphology, as well as increased expression of Dpp4, a mitochondria-encoded gene responsible for ferroptosis induction in the uteri of rats co-exposed to DHT and insulin. However, in the placenta, DHT and insulin exposure only partially altered the expression of ferroptosis-related markers (e.g. region-dependent GPX4, glutathione + glutathione disulfide, malondialdehyde, Gls2 and Slc7a11 mRNAs, and phosphorylated p38 levels). Moreover, we found decreased expression of Dpp4 mRNA and increased expression of Cisd1 mRNA in placentas of rats co-exposed to DHT and insulin. Further, DHT + insulin-exposed pregnant rats exhibited decreased apoptosis in the uterus and increased necroptosis in the placenta. Our findings suggest that maternal hyperandrogenism and insulin resistance causes the activation of ferroptosis in the gravid uterus and placenta, although this is mediated via different mechanisms operating at the molecular and cellular levels. Our data also suggest that apoptosis and necroptosis may play a role in coordinating or compensating for hyperandrogenism and insulin-resistance-induced ferroptosis when the gravid uterus and placenta are dysfunctional.