Normal Development Research Articles

Hyperandrogenic environment regulates the function of ovarian granulosa cells by modulating macrophage polarization in PCOS.

Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder characterized by oligo-anovulation, hyperandrogenism, and polycystic ovaries, with hyperandrogenism being the most prominent feature of PCOS patients. However, whether excessive androgens also exist in the ovarian microenvironment of patients with PCOS, and their modulatory role on ovarian immune homeostasis and ovarian function, is not clear. Follicular fluid samples from patients participating in their first in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment were collected. Androgen concentration of follicular fluid was assayed by chemiluminescence, and the macrophage M1:M2 ratio was detected by flow cytometry. In an in vitro model, we examined the regulatory effects of different concentrations of androgen on macrophage differentiation and glucose metabolism levels using qRT-PCR, Simple Western and multi-factor flow cytometry assay. In a co-culture model, we assessed the effect of a hyperandrogenic environment in the presence or absence of macrophages on the function of granulosacells using qRT-PCR, Simple Western, EdU assay, cell cycle assay, and multi-factor flow cytometry assay. The results showed that a significantly higher androgen level and M1:M2 ratio in the follicular fluid of PCOS patients with hyperandrogenism. The hyperandrogenic environment promoted the expression of pro-inflammatory and glycolysis-related molecules and inhibited the expression of anti-inflammatory and oxidative phosphorylation-related molecules in macrophages. In the presence of macrophages, a hyperandrogenic environment significantly downregulated the function of granulosa cells. There is a hyperandrogenic microenvironment in the ovary of PCOS patients with hyperandrogenism. Hyperandrogenic microenvironment can promote the activation of ovarian macrophages to M1, which may be associated with the reprogramming of macrophage glucose metabolism. The increased secretion of pro-inflammatory cytokines by macrophages in the hyperandrogenic microenvironment would impair the normal function of granulosa cells and interfere with normal ovarian follicle growth and development.

Systemic phospho-defective and phospho-mimetic Drp1 mice exhibit normal growth and development with altered anxiety-like behavior

Systemic phospho-defective and phospho-mimetic Drp1 mice exhibit normal growth and development with altered anxiety-like behavior

E2F transcription factors promote tumorigenicity in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers with limited treatment options, illustrating an urgent need to identify new drugable targets in PDACs. Using the similarities between tumor development and normal embryonic development, which is accompanied by rapid cell expansion, we aimed to identify and characterize embryonic signaling pathways that were reinitiated during tumor formation and expansion. Here, we report that the transcription factors E2F1 and E2F8 are potential key regulators in PDAC. E2F1 and E2F8 RNA expression is mainly localized in proliferating cells in the developing pancreas and in malignant ductal cells in PDAC. Silencing of E2F1 and E2F8 in PANC-1 pancreatic tumor cells inhibited cell proliferation and impaired cell spreading and migration. Moreover, loss of E2F1 also affected cell viability and apoptosis with E2F expression in PDAC tissues correlating with expression of apoptosis and mitosis pathway genes, suggesting that E2F factors promote cell cycle regulation and tumorigenesis in PDAC cells. Our findings illustrate that E2F1 and E2F8 transcription factors are expressed in pancreatic progenitor and PDAC cells, where they contribute to tumor cell expansion by regulation of cell proliferation, viability, and cell migration making these genes attractive therapeutic targets and potential prognostic markers for pancreatic cancer.

How does the burial rate control the diagenesis of sandstone? Insights from a diagenetic physical simulation experiment

The study conducted physical simulation experiments on sandstone samples from the Junggar Basin to investigate how burial rates influence sandstone diagenesis and reservoir quality. Results show that the mechanical compaction under a negative burial rate (tectonic uplift) almost stops to destroy the sandstone reservoir space, the capacity of fluid seepage is the strongest and the sandstone tends to develop ‘weak compaction–strong dissolution’ diagenetic facies. For positive burial rates, sandstones with a low burial rate tend to develop ‘medium compaction–medium dissolution’ diagenetic facies; sandstones at a medium burial rate easily form ‘strong compaction–weak dissolution’ diagenetic facies, and sandstones at a high burial rate tend to develop ‘weak compaction–weak dissolution’ diagenetic facies. Experimental results indicate that the compaction strength and damage to sandstone reservoirs may not consistently rise with the burial rate. Faster burial rates do not always intensify compaction; the degree of compaction depends on fluid overpressure. If the increase in burial rate does not induce the fluid overpressure in sandstones, the burial rate is higher and the destruction degree of primary pores caused by mechanical compaction is greater; mechanical compaction also simultaneously causes the diagenetic system to be more closed and the dissolution to be weaker. If the increase in burial rate can induce the fluid overpressure in sandstones, the burial rate is higher, the inhibition of mechanical compaction by fluid overpressure is more pronounced. However, fluid overpressure also strengthens the closure of the diagenetic system, hindering the injection of external acidic fluids into the sandstone, which is not conducive to dissolution. Overall, low burial rates with normal pressure favour secondary pore development, high burial rates with overpressure preserve primary pores, while medium burial rates with normal pressure are unfavourable for primary and secondary pores.

Addressing cortex dysregulation in youth through brain health check coaching and prophylactic brain development.

The Carter Center has estimated that the addiction crisis in the United States (US), if continues to worsen at the same rate, may cost the country approximately 16 trillion dollars by 2030. In recent years, the well-being of youth has been compromised by not only the coronavirus disease 2019 pandemic but also the alarming global opioid crisis, particularly in the US. Each year, deadly opioid drugs claim hundreds of thousands of lives, contributing to an ever-rising death toll. In addition, maternal usage of opioids and other drugs during pregnancy could compromise the neurodevelopment of children. A high rate of DNA polymorphic antecedents compounds the occurrence of epigenetic insults involving methylation of specific essential genes related to normal brain function. These genetic antecedent insults affect healthy DNA and mRNA transcription, leading to a loss of proteins required for normal brain development and function in youth. Myelination in the frontal cortex, a process known to extend until the late 20s, delays the development of proficient executive function and decision-making abilities. Understanding this delay in brain development, along with the presence of potential high-risk antecedent polymorphic variants or alleles and generational epigenetics, provides a clear rationale for embracing the Brain Research Commission's suggestion to mimic fitness programs with an adaptable brain health check (BHC). Implementing the BHC within the educational systems in the US and other countries could serve as an effective initiative for proactive therapies aimed at reducing juvenile mental health problems and eventually criminal activities, addiction, and other behaviors associated with reward deficiency syndrome.

Restoration of Pregnancy Function Using a GT/PCL Biofilm in a Rabbit Model of Uterine Injury.

Biomaterial scaffolds have been used successfully to promote the regenerative repair of small endometrial lesions in small rodents, providing partial restoration of gestational function. The use of rabbits in this study allowed us to investigate a larger endometrial tissue defect and myometrial injury model. A gelatin/polycaprolactone (GT/PCL) gradient-layer biofilm was sutured at the defect to guide the reconstruction of the original tissue structure. Twenty-eight days postimplantation, the uterine cavity had been restored to its original morphology, endometrial growth was accompanied by the formation of glands and blood vessels, and the fragmented myofibers of the uterine smooth muscle had begun to resemble the normal structure of the lagomorph uterine cavity, arranging in a circular luminal pattern and a longitudinal serosal pattern. In addition, the repair site supported both embryonic implantation into the placenta and normal embryonic development. Four-dimensional label-free proteomic analysis identified the cell adhesion molecules, phagosome, ferroptosis, rap1 signaling pathways, hematopoietic cell lineage, complement and coagulation cascades, tricarboxylic acid cycle, carbon metabolism, and hypoxia inducible factor (HIF)-1 signaling pathways as important in the endogenous repair process of uterine tissue injury, and acetylation of protein modification sites upregulated these signaling pathways.

Exploring vasculogenesis in the normal human kidney and clear cell renal cell carcinoma: insights from development to tumor progression and biomarkers for therapy response.

Vasculogenesis, which refers to the development of blood vessels from precursor cells, is a process that occurs predominantly during early embryonic life. It plays a crucial role in the establishment of the primitive vascular network. Vasculogenesis diminishes throughout the fetal vascular remodeling process, giving way to angiogenesis, which becomes the predominant mechanism after birth. At first, the development of the kidney's blood vessels depends on vasculogenesis, and then both vasculogenesis and angiogenesis happen simultaneously. Both processes are necessary for the normal development of the renal vasculature. Although the kidneys are highly vascularized, our understanding of normal kidney vasculogenesis is still incomplete. This lack of knowledge may explain the limited data available on the role of vasculogenesis in the progression and spread of renal cancers. In other types of cancer, researchers have well documented the phenomenon of tumor vasculogenesis. However, there is currently limited and fragmented information about the occurrence of clear-cell renal cell carcinomas (cc-RCC). In this article, we provide a comprehensive review of the current understanding of normal kidney vasculogenesis and vasculogenic pathways in clear cell renal cell carcinoma (cc-RCC). We specifically focus on cellular precursors, growth factors, and the influence of the normal and tumor environments on these processes. It will carefully look at how tumor vasculogenesis might affect the growth and metastasis of clear cell renal cell carcinoma (cc-RCC), as well as how it might affect the effectiveness of drugs and the development of therapy resistance.

Temporal dynamics of apoptosis-induced proliferation in pupal wing development: implications for regenerative ability

BackgroundThe ability of animals to regenerate damaged tissue is a complex process that involves various cellular mechanisms. As animals age, they lose their regenerative abilities, making it essential to understand the underlying mechanisms that limit regenerative ability during aging. Drosophila melanogaster wing imaginal discs are epithelial structures that can regenerate after tissue injury. While significant research has focused on investigating regenerative responses during larval stages our comprehension of the regenerative potential of pupal wings and the underlying mechanisms contributing to the decline of regenerative responses remains limited.ResultsHere, we explore the temporal dynamics during pupal development of the proliferative response triggered by the induction of cell death, a typical regenerative response. Our results indicate that the apoptosis-induced proliferative response can continue until 34 h after puparium formation (APF), beyond this point cell death alone is not sufficient to induce a regenerative response. Under normal circumstances, cell proliferation ceases around 24 h APF. Interestingly, the failure of reinitiating the cell cycle beyond this time point is not attributed to an incapacity to activate the JNK pathway. Instead, our results suggest that the function of the ecdysone-responsive transcription factor E93 is involved in limiting the apoptosis-induced proliferative response during pupal development.ConclusionsOur study shows that apoptosis can prolong the proliferative period of cells in the wing during pupal development as late as 34 h APF, at least 10 h longer than during normal development. After this time point, the regenerative response is diminished, a process mediated in part by the ecdysone-responsive transcription factor E93.

Modeling insect growth regulators for pest management.

Insect growth regulators (IGRs) have been developed as effective control measures against harmful insect pests to disrupt their normal development. This study is to propose a mathematical model to evaluate the cost-effectiveness of IGRs for pest management. The key features of the model include the temperature-dependent growth of insects and realistic impulsive IGRs releasing strategies. The impulsive releases are carefully modeled by counting the number of implements during an insect's temperature-dependent development duration, which introduces a surviving probability determined by a product of terms corresponding to each release. Dynamical behavior of the model is illustrated through dynamical system analysis and a threshold-type result is established in terms of the net reproduction number. Further numerical simulations are performed to quantitatively evaluate the effectiveness of IGRs to control populations of harmful insect pests. It is interesting to observe that the time-changing environment plays an important role in determining an optimal pest control scheme with appropriate release frequencies and time instants.

Optical coherence tomography-guided Brillouin microscopy highlights regional tissue stiffness differences during anterior neural tube closure in the Mthfd1l murine mutant.

Neurulation is a highly synchronized biomechanical process leading to the formation of the brain and spinal cord, and its failure leads to neural tube defects (NTDs). Although we are rapidly learning the genetic mechanisms underlying NTDs, the biomechanical aspects are largely unknown. To understand the correlation between NTDs and tissue stiffness during neural tube closure (NTC), we imaged an NTD murine model using optical coherence tomography (OCT), Brillouin microscopy, and confocal fluorescence microscopy. Here, we associate structural information from OCT with local stiffness from the Brillouin signal of embryos undergoing neurulation. The stiffness of neuroepithelial tissues in Mthfd1l null embryos was significantly lower than that of wild-type embryos. Additionally, exogenous formate supplementation improved tissue stiffness and gross embryonic morphology in nullizygous and heterozygous embryos. Our results demonstrate the significance of proper tissue stiffness in normal NTC and pave the way for future studies on the mechanobiology of normal and abnormal embryonic development.

The role of SLC26A4 in bony labyrinth development and otoconial mineralization in mouse models.

Inner ear malformations are predominantly attributed to developmental arrest during the embryonic stage of membranous labyrinth development. Due to the inherent difficulty in clinically assessing the status of the membranous labyrinth, these malformations are diagnosed with radiographic imaging, based on the morphological characteristics of the bony labyrinth. While extensive research has elucidated the intricacies of membranous labyrinth development in mouse models, comprehensive investigations into the developmental trajectory of the bony labyrinth, especially about its calcification process, have been notably lacking. One of the most prominent types of inner ear malformations is known as incomplete partition (IP), characterized by nearly normal external cochlear appearance but pronounced irregularities in the morphology of the modiolus and inter-scalar septa. IP type II (IP-II), also known as Mondini dysplasia, is generally accompanied by an enlargement of the vestibular aqueduct and is primarily attributed to mutations in the SLC26A4 gene. In the case of IP-II, the modiolus and inter-scalar septa of the cochlear apex are underdeveloped or missing, resulting in the manifestation of a cystic structure on radiographic imaging. In this overview, we not only explore the normal development of the bony labyrinth in mice but also present our observations on otolith mineralization. Furthermore, we investigated the specifics of bony labyrinth and otolith mineralization in Slc26a4-deficient mice, which served as an animal model for IP-II. We ensured that these findings promise to provide valuable insights for the establishment of therapeutic interventions, optimal timing, targeted sites, and preventive measures when considering the management of this condition.

Maternal supplementation with edible birds' nest during gestation and lactation enhances intestinal barrier function by upregulating Claudin-1 in rat offspring

Maternal diet is indispensable for the proper development of offspring, and the establishment of a well-functioning intestinal barrier is crucial for normal growth and development. Edible bird’s nest (EBN) has positive impacts on intestinal health, but the underlying mechanisms are unknown. Our study showed that maternal EBN supplementation downregulated the serum levels of diamine oxidase and D-lactate, elevated expression of tight junction proteins ZO-1, Occludin, and Claudin-1, and regulated the intestinal microbiota in rat offspring. Spearman’s correlation analysis revealed that Claudin-1, transforming growth factor-β (TGF-β), and transcription factor RUNX3 were positively correlated with changes in intestinal bacteria. EBN may upregulate the expression of TGF-β by modulating the intestinal microbiota composition, enhancing RUNX3 binding to the Claudin-1 promoter region to upregulate its expression. In conclusion, we demonstrated that maternal EBN supplementation during gestation and lactation enhanced intestinal barrier function by upregulating Claudin-1 in rat offspring.

Разработка и реализация протокола поведенческого эксперимента для оценки когнитивных способностей и социального поведения мышей после стресса в раннем возрасте

<p style="text-align: justify;">This manuscript presents a protocol designed for the comprehensive investigation of early life stress (ELS) outcomes and a feasibility study conducted with this protocol. ELS alters normal development by interfering at various levels: hormonal changes, brain cellular architecture, epigenome, and chromosomal structural elements. The protocol combines classic behavioral tests with advanced molecular techniques to obtain comprehensive data and thus uncover the underlying mechanisms of ELS. In this protocol, the main source of stress is maternal separation. Briefly, a group of C57Bl/6 mice undergoes maternal separation; then, mice perform the radial maze test and the resident-intruder test. As a control, another group of mice stays undisturbed and performs the same behavioral tests in the same timeframe. After the behavioral tests, biosamples are collected, including urine for corticosterone measurements, peripheral blood, hippocampus, amygdala, and prefrontal cortex tissues for DNA isolation and its downstream analyses (DNA methylation profiling and telomere length measuring), and whole brains for immunohistochemistry analysis of the glucocorticoid receptor density. This protocol was successfully tested as a feasibility study for a large-scale investigation that addresses potential flaws to establish a robust methodology. This paper reports on a comprehensive approach to examining multiple aspects of development that interrogates a holistic analysis of multilayer and multidimensional data and may contribute valuable insights for both animal and human studies.</p>

Features of speech disorders in children with epileptic encephalopathies

Introduction. Speech disorders are a common problem in childhood. Speech disorders of various types are, in particular, the most common complications of epilepsy.
 Objective. The clinical manifestations of speech disorders in children with epileptic encephalopathies were studied.
 Materials and methods. The study included eighty nine children with epileptic encephalopathies. All patients underwent a detailed study of the anamnesis of life and disease, assessment of neurological and somatic, analysis of the semiotics of seizures, assessment of the therapy received, articulatory praxis, phonemic perception, game activity, expressive speech, impressive speech.
 Results. Speech in the examined patients had the character of a gross violation after the stage of normal development (37.1%), speech development delay was noted in 38.2% of patients from birth. Phonemic perception was impaired in 73 (82.0%) patients, a violation of articulatory praxis was detected in 63 (70.8%) patients, coherent speech was not formed in 78 (87.6%) patients, play activity did not correspond to the age of the child in 50 ( 56.2%) cases, violation of the account was detected in 69 (77.5%) patients, violation of sound pronunciation was observed in 30 (33.7%) patients. 
 Conclusion. Articulatory apraxia and motor alalia are the most common types of speech disorders in children with epileptic encephalopathies.

Hypoxia delays steroid-induced developmental maturation in Drosophila by suppressing EGF signaling.

Animals often grow and develop in unpredictable environments where factors like food availability, temperature, and oxygen levels can fluctuate dramatically. To ensure proper sexual maturation into adulthood, juvenile animals need to adapt their growth and developmental rates to these fluctuating environmental conditions. Failure to do so can result in impaired maturation and incorrect body size. Here we describe a mechanism by which Drosophila larvae adapt their development in low oxygen (hypoxia). During normal development, larvae grow and increase in mass until they reach critical weight (CW), after which point a neuroendocrine circuit triggers the production of the steroid hormone ecdysone from the prothoracic gland (PG), which promotes maturation to the pupal stage. However, when raised in hypoxia (5% oxygen), larvae slow their growth and delay their maturation to the pupal stage. We find that, although hypoxia delays the attainment of CW, the maturation delay occurs mainly because of hypoxia acting late in development to suppress ecdysone production. This suppression operates through a distinct mechanism from nutrient deprivation, occurs independently of HIF-1 alpha and does not involve dilp8 or modulation of Ptth, the main neuropeptide that initiates ecdysone production in the PG. Instead, we find that hypoxia lowers the expression of the EGF ligand, spitz, and that the delay in maturation occurs due to reduced EGFR/ERK signaling in the PG. Our study sheds light on how animals can adjust their development rate in response to changing oxygen levels in their environment. Given that hypoxia is a feature of both normal physiology and many diseases, our findings have important implications for understanding how low oxygen levels may impact animal development in both normal and pathological situations.

Irisin combined index to diagnose central precocious puberty in girls: a cross-sectional study

BackgroundTo investigate serum irisin levels in girls at different developmental status and explore the significance of irisin for the diagnosis of central precocious puberty (CPP) in girls.MethodsIn this cross-sectional study 111 girls were enrolled, including 43 cases of CPP, 44 cases of peripheral precocious puberty (PPP) and 24 cases of girls with normal sexual development as controls. The data on age, weight and height, measured blood levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol, and irisin were collected. Pelvic Doppler ultrasound was performed to evaluate uterine length, transverse diameter, anteroposterior diameter. The girls were divided into non-CPP group and CPP group according to gonadotropin-releasing hormone (GnRH) stimulation test.ResultsSerum irisin levels were significantly higher in CPP group than in PPP group and normal control group. Serum irisin level was positively correlated with basal LH level, basal FSH level, peak LH level, peak LH /FSH ratio, uterine volume, bone age, and bone age index. The area under the curve, cut-off value, sensitivity and specificity of serum irisin were 0.958, 219.255 pg/ml, 100% and 80.6%. The combined diagnosis of CPP in girls by serum irisin and serum basal LH combined with uterine volume had an AUC, sensitivity, and specificity of 0.994, 97.6%, and 100%, superior to that of the single index.ConclusionsSerum irisin level in girls with CPP is significantly increased. An irisin combined index could help the diagnosis of CPP in girls.

Maternal Diet High in Linoleic Acid Alters Renal Branching Morphogenesis and mTOR/AKT Signalling Genes in Rat Fetal Kidneys.

Linoleic acid (LA), an n-6 polyunsaturated fatty acid (PUFA), is obtained from the maternal diet during pregnancy, and is essential for normal fetal growth and development. A maternal high-LA (HLA) diet alters maternal and offspring fatty acids, maternal leptin and male/female ratio at embryonic (E) day 20 (E20). We investigated the effects of an HLA diet on embryonic offspring renal branching morphogenesis, leptin signalling, megalin signalling and angiogenesis gene expression. Female Wistar Kyoto rats were fed low-LA (LLA; 1.44% energy from LA) or high-LA (HLA; 6.21% energy from LA) diets during pregnancy and gestation/lactation. Offspring were sacrificed and mRNA from kidneys was analysed by real-time PCR. Maternal HLA decreased the targets involved in branching morphogenesis Ret and Gdnf in offspring, independent of sex. Furthermore, downstream targets of megalin, namely mTOR, Akt3 and Prkab2, were reduced in offspring from mothers consuming an HLA diet, independent of sex. There was a trend of an increase in the branching morphogenesis target Gfra1 in females (p = 0.0517). These findings suggest that an HLA diet during pregnancy may lead to altered renal function in offspring. Future research should investigate the effects an HLA diet has on offspring kidney function in adolescence and adulthood.

Hemicellulose modification and cell wall genetic improvement in plants

Hemicellulose, as a primary component of plant cell walls, constitutes approximately one third of cell wall dry matter and ranks as the second abundant renewable biomass resource in the nature after cellulose. Hemicellulose is tightly cross-linked with cellulose, lignin and other components in the plant cell wall, leading to lignocellulose recalcitrance. However, precise genetic modifications of plant cell walls can significantly improve the saccharification efficiency of lignocellulose while ensuring normal plant growth and development. We comprehensively review the research progress in the structural distribution of hemicellulose in plant cell walls, the cross-linking between hemicellulose and other components of the cell wall, and the impact of hemicellulose modification on the saccharification efficiency of the cell wall, proving a reference for the genetic improvement of energy crops.

Low toxicity of magnetite-based modified bionanocomposites with potential application for wastewater treatment: Evaluation in a zebrafish animal model

In recent years, the escalating concerns surrounding environmental pollution and the need for sustainable wastewater treatment solutions have underscored the significance of developing technologies that can efficiently treat wastewater while also reducing negative ecological effects. In this context, our study aims to contribute to the advancement of sustainable technologies for wastewater treatment, by investigating the effects that bare magnetite nanoparticles and those functionalized with the enzyme laccase could have in an aquatic animal, zebrafish, at various life cycle stages. Exposure to magnetite nanoparticles shows some effects on embryo hatching, survival rates, or larval behavior at higher concentrations. For both treatments, the hatching percentages were close to 80% compared to 93% for the control group. At the end of the observations in larvae, survival in all the evaluated groups was higher than 90%. Additionally, we evaluated the accumulation of nanoparticles in various stages of zebrafish. We found that, although there was accumulation during embryonic stages, it did not affect normal development or subsequent hatching. Iron levels in different organs such as gills, muscles, gastrointestinal tract, and brain were also evaluated in adults. Animals treated with a mix of food and nanoparticles at 10 μg/mL (Food group) presented a higher concentration of iron accumulation in muscle, gastrointestinal tract, and gills compared to the untreated control group. Although iron levels increased depending on the dose and exposure method applied, they were not statistically significant from the control groups. Our findings suggest that bionanocomposites evaluated here can be considered safe for removal of contaminants in wastewater without toxic effects or detrimental accumulation fish's health.

CD44 Expression in Clear Cell Renal Cell Carcinoma (ccRCC) Correlates with Tumor Grade and Patient Survival and Is Affected by Gene Methylation

Clear cell RCC (ccRCC) represents the most common type of kidney cancer, with surgery being the only potential curative treatment. Almost one-third of ccRCC patients relapse either locally or as cases of distant metastases. Several biomarkers have been employed in order to separate ccRCC patients with better prognosis or to predict treatment outcomes, with limited results. CD44 is a membrane glycoprotein with multiple roles in normal development but also cancer. Recently, the CD44 standard isoform has been implicated in tumor progression and the metastasis cascade through microenvironment interactions. Here, through CD44 immunohistochemical staining of ccRCC patient samples and TCGA data analysis, we sought to elucidate the expression patterns (mRNA and protein) of CD44 in clear cell RCC and correlate its expression with clinicopathological parameters. We were able to show that CD44 expression presents a positive association with tumor grade and overall survival, predicting a worse patient outcome in ccRCC. In addition, our data indicate that the CD44 mRNA upregulation can be attributed to reduced gene methylation, implicating epigenetic gene regulation in ccRCC development and progression.