Expression profiles of urine exosomal tRNA-derived small RNAs and their potential roles in calcium oxalate stone disease.

Background and objective: Exosomes have been confirmed to be implicated in the pathogenesis of calcium oxalate (CaOx) stones. tRNA-derived small RNAs (tsRNAs) are among the oldest small RNAs involved in exosome-mediated intercellular communication, yet their role in kidney stones remains unexplored. This pilot study aimed to identify differentially expressed tsRNAs (DEtsRNAs) in urine exosomes between CaOx stone patients and healthy controls and explore their potential roles in nephrolithiasis. Method: First-morning urine samples were collected from three CaOx stone patients and three healthy controls. Urinary exosomes were isolated and analyzed by high-throughput sequencing to generate the expression profiles of tsRNAs and detect DEtsRNAs. Predicted target genes of DEtsRNAs were subjected to functional enrichment analysis. The authors also combined the public dataset GSE73680 to investigate how DEtsRNAs were related to stone formation. Results: Four DEtsRNAs were significantly upregulated in CaOx stone patients compared to healthy controls. tRF-Lys-TTT-5005c was the most elevated, followed by tRF-Lys-CTT-5006c, tRF-Ala-AGC-5017b, and tRF-Gly-CCC-5004b. Bioinformatics analysis indicated that these four types of DEtsRNAs might serve distinct biological functions. Combined with data mining from the public dataset GSE73680, the authors assumed that exosomes carrying tRF-Lys-TTT-5005c and tRF-Lys-CTT-5006c could inhibit the expression of SMAD6, FBN1, and FZD1, thereby activating the BMP signaling pathway, which might induce an osteogenic-like transformation in target cells, resulting in the formation of Randall's plaques and CaOx stones. Conclusion: The authors' findings shed light on the potential roles of tsRNAs in the pathogenesis of CaOx stone disease, highlighting exosomal DEtsRNAs as promising diagnostic biomarkers and therapeutic targets in nephrolithiasis.

Recent breakthroughs in innovative elements, multidimensional enhancements, derived technologies, and novel applications of PROTACs.

Proteolysis Targeting Chimera (PROTAC) is an emerging and evolving technology based on targeted protein degradation (TPD). Small molecule PROTACs have shown great efficacy in degrading disease-specific proteins in preclinical and clinical studies, but also showed various limitations. In recent years, new technologies and advances in TPD have provided additional optimized strategies based on conventional PROTACs that can overcome the shortcomings of conventional PROTACs in terms of undruggable targets, bioavailability, tissue-specificity, spatiotemporal control, and degradation scope. In addition, some designs of special targeting chimeras and applications based on multidisciplinary science have shed light on novel therapeutic modalities and drug design. However, each improvement has its own advantages, disadvantages and application conditions. In this review, we summarize the exploration of PROTAC elements, depict a landscape of improvements and derived concepts of PROTACs, and expect to provide perspectives for technological innovations, combinations and applications in future targeting chimera design.

The Involvement of Endoplasmic Reticulum Stress during the Interaction between Calcium Oxalate Crystals and Renal Tubular Epithelial Cells.

Our study aimed to elucidate the mechanisms behind the interaction between calcium oxalate (CaOx) crystals and renal tubular epithelial cells through transcriptome sequencing analysis. HK-2 cells were stimulated with or without CaOx monohydrate crystals and subjected to RNA-seq to assess the effects of CaOx crystals on gene expression changes, key pathways, and molecular players during this interaction. A total of 629 differentially expressed genes (DEGs) were identified between the control group and experimental group, with 491 genes up-regulated and 138 down-regulated. Functional enrichment analysis indicated that the DEGs were significantly associated with endoplasmic reticulum stress (ERS) and unfolded protein response. To validate our findings, we compared our results with the public dataset GSE73680 and confirmed the increased expression of two ERS-related DEGs, CHAC1 and FGF21, in renal papillary tissues from patients with CaOx stones. Collectively, these findings suggest that ERS plays a crucial role in the crystal-cell interaction and highlight the potential for developing therapeutic strategies aimed at reducing CaOx stone formation by targeting ERS-related molecules and pathways.

Identification of Two Clusters in Renal Pelvis Urobiome of Unilateral Stone Formers Using 2bRAD-M.

Urolithiasis is a common urological disease with increasing incidence and a high recurrence rate, whose etiology is not fully understood. The application of sequencing and culturomics has revealed that urolithiasis is closely related to the urinary microbiome (urobiome), shedding new light on the pathogenesis of stone formation. In this study, we recruited 30 patients with unilateral stones and collected their renal pelvis urine from both sides. Then, we performed 2bRAD-M, a novel sequencing technique that provides precise microbial identification at the species level, to characterize the renal pelvis urobiome of unilateral stone formers in the both sides. We first found that the urobiome in the stone side could be divided into two clusters (Stone1 and Stone2) based on distance algorithms. Stone2 harbored higher microbial richness and diversity compared to Stone1. The genera Cupriavidus and Sphingomonas were overrepresented in Stone1, whereas Acinetobacter and Pseudomonas were overrepresented in Stone2. Meanwhile, differential species were identified between Stone1 and Stone2. We further constructed a random forest model to discriminate two clusters which achieved a powerful diagnostic potential. Moreover, the urobiome of the non-stone side (Control1/2) was compared with that of the stone side (Stone1/2). Stone1 and Control1 showed different microbial community distributions, while Stone2 was similar to Control2 based on diversity analysis. We also identified differentially abundant species among all groups. We assumed that there might be different mechanisms of how microbiota contribute to stone formation in two clusters. Our findings might assist in the selection of suitable medical treatments for urolithiasis.

Interconnections between urolithiasis and oral health: a cross-sectional and bidirectional Mendelian randomization study.

Introduction: Urolithiasis is one of the most common diseases for urologists and it is a heavy burden for stone formers and society. The theory of the oral-genitourinary axis casts novel light on the pathological process of genitourinary system diseases. Hence, we performed this study to characterize the crosstalk between oral health conditions and urolithiasis to provide evidence for prevention measures and mechanisms of stone formation. Materials and methods: This population-based cross-sectional study included 86,548 Chinese individuals who had undergone a comprehensive examination in 2017. Urolithiasis was diagnosed depending on the results of ultrasonographic imaging. Logistic models were utilized to characterize the association between oral health conditions and urolithiasis. We further applied bidirectional Mendelian randomization to explore the causality between oral health conditions and urolithiasis. Results: We observed that presenting caries indicated a negative correlation with the risk for urolithiasis while presenting gingivitis [OR (95% CI), 2.021 (1.866-2.187)] and impacted tooth [OR (95% CI), 1.312 (1.219-1.411)] shown to be positively associated with urolithiasis. Furthermore, we discovered that genetically predicted gingivitis was associated with a higher risk of urolithiasis [OR (95% CI), 1.174 (1.009-1.366)] and causality from urolithiasis to impacted teeth [OR(95% CI), 1.207 (1.027-1.418)] through bidirectional Mendelian randomization. Conclusion: The results cast new light on the risk factor and pathogenesis of kidney stone formation and could provide novel evidence for the oral-genitourinary axis and the systematic inflammatory network. Our findings could also offer suggestions for tailored clinical prevention strategies against stone diseases.