Recent advancements in single-cell analysis have revolutionized our understanding of cellular heterogeneity, particularly in lipid metabolism. Single-cell lipidomics, enabled by ultra-sensitive mass spectrometry techniques such as Orbitrap and Fourier-transform ion cyclotron resonance (FT-ICR), provides unprecedented insights into lipid-mediated cellular functions. Unlike bulk analyses, single-cell approaches capture real-time metabolic changes, highlighting lipid species' roles in cell differentiation, signal transduction, and disease progression. Mass spectrometry imaging (MSI), including MALDI-MSI and SIMS, further delineates lipid distributions within tissues, revealing spatial heterogeneity critical to cellular function. Emerging evidence suggests that lipid alterations significantly impact developmental mechanisms, stem cell niches, and disease pathogenesis, challenging conventional bulk-level assumptions. However, a key challenge remains in deciphering how lipid networks coordinate cellular differentiation and transcriptional regulation. Future research must integrate lipidomic, proteomic, and genomic data to unravel lipid-mediated signaling and epigenetic modifications. Understanding these dynamics will advance regenerative medicine and therapeutic interventions, enabling precise targeting of lipid-driven pathways in disease contexts.
All eukaryotic cell surfaces are coated with various types of glycans, which are essential molecules in biological events. In this review, we summarize recent integrated glycomics studies using various biological samples. We introduce an improved sialic acid linkage-specific alkylamidation (SALSA) method for sialylated glycan analysis and an automated glycosphingolipid-glycan preparation system for large-scale glycomic analysis of human plasma/serum. Finally, we explain the importance of integrated glycomics of glycoconjugates through total glycomic analysis of human serum and mouse brain tissue, and discuss prospects for exploring glycans as effective biomarkers of biological phenomena.
Rare sugars are defined as monosaccharides and their derivatives that do not exist in nature at all or that exist in extremely limited amounts despite being theoretically possible. At present, no comprehensive dogma has been presented regarding how and why these rare sugars have deviated from the naturally selected monosaccharides. In this minireview, we adopt a hypothesis on the origin and evolution of elementary hexoses, previously presented by one of the authors (Hirabayashi, Q Rev Biol, 1996, 71:365-380). In this scenario, monosaccharides, which constitute various kinds of glycans in nature, are assumed to have been generated by formose reactions on the prebiotic Earth (chemical evolution era). Among them, the most stable hexoses, i.e., fructose, glucose, and mannose remained accumulated. After the birth of life, the "chemical origin" saccharides thus survived were transformed into a variety of "bricolage products", which include galactose and other recognition saccharides like fucose and sialic acid through the invention of diverse metabolic pathways (biological evolution era). The remaining monosaccharides that have deviated from this scenario are considered rare sugars. If we can produce rare sugars as we wish, it is expected that various more useful biomaterials will be created by using them as raw materials. Thanks to the pioneering research of the Izumori group in the 1990's, and to a few other investigations by other groups, almost all monosaccharides including l-sugars can now be produced by combining both chemical and enzymatic approaches. After briefly giving an overview of the origin of elementary hexoses and the current state of the rare sugar production, we will look ahead to the next generation of monosaccharide research which also targets glycosides including disaccharides.
In recent years, the concept of neuro-skeletal crosstalk, highlighting the reciprocal interactions between the nervous and skeletal systems, has opened new avenues for understanding the pathogenesis and intervention strategies of complex diseases. This review summarizes the roles of molecular networks such as neurotransmitters, endocrine factors, immune mediators, and extracellular vesicles in bone metabolism, repair, and neurodegenerative diseases, with an emphasis on recent advances regarding bone-derived signals-including the Piezo1 channel and osteocalcin-in neural regulation. Building on this foundation, we focus on advances in frontier materials such as nanomaterials and hydrogels for modulating the brain-bone microenvironment and facilitating coordinated tissue regeneration, as well as new strategies for targeted drug delivery and immune microenvironment modulation. Empowered by next-generation technologies-including multi-omics, artificial intelligence, and organ-on-a-chip systems-the investigation of the fundamental mechanisms and personalized interventions of the brain-bone axis is entering a new era of opportunity. We hope that this review will provide a theoretical basis and valuable reference for future mechanistic studies and innovation in this interdisciplinary field. By elucidating bidirectional regulatory networks, this review underscores the significant translational potential of targeting the brain-bone axis (BBA) for the treatment of skeletal disorders and neurodegenerative comorbidities. Therapeutic strategies harnessing neurotransmitters (e.g., norepinephrine, serotonin) and neuropeptides (e.g., CGRP) can directly modulate osteoblastic/osteoclastic activity and immune responses, thereby orchestrating fracture repair and metabolic homeostasis. The integration of functional materials-such as stimuli-responsive hydrogels, nanomaterials, and bioelectronic devices-enhances the spatiotemporal precision of signal modulation and facilitates drug delivery across biological barriers, including the blood-brain barrier (BBB). However, challenges regarding low cross-organ targeting efficiency, the complexity of dynamic pathological microenvironments, and physiological discrepancies between animal models and humans necessitate further optimization. Advances in multi-omics analysis, AI-driven network modeling, and intelligent biomimetic delivery systems hold promise for bridging these gaps, offering scalable solutions for clinical translation. This work highlights neuro-skeletal modulation as a transformative dual-targeting strategy for complex diseases, yet its implementation remains contingent upon the refinement of precise intervention technologies and rigorous clinical validation.
Human colostrum and mature milk contain oligosaccharides (Os), designated as human milk oligosaccharides (HMOs). Approximately 200 varieties of HMOs have been characterized. Although HMOs are not utilized as an energy source by infants, they have important protective functions, including pathogenic bacteria and viral infection inhibitors and immune modulators, among other functions, and HMOs stimulate brain-nerve development. The Os concentration is average 11 g/L in human milk but >100 mg/L in mature bovine milk, which is used to manufacture infant formula, suggesting that human-identical milk oligosaccharides (HiMOs) should be incorporated into milk substitutes. Some infant formulas incorporating 2'-fucosyllactose and lacto-N-neotetraose are now commercially available, and intervention trials have been concluded. We review basic HMO information, including their chemical structures and concentrations, attempts to synthesize HMOs at small and plant scale, studies that clarified HMO biological functions, and interventions with milk substitutes incorporating HiMOs in formula-fed infants.
OBJECTIVE: This study aimed to construct a perovskite quantum dot probe targeting isocitrate dehydrogenase 1 (IDH1) mutation. The probe is intended to enable rapid in vitro pathological diagnosis of IDH1-mutant glioma, guide surgeons in formulating scientific and rational resection strategies during surgery, and facilitate precise individualized intraoperative treatment for glioma patients. METHODS: Via surface ligand engineering, a perovskite nanocrystal (PNC) probe modified with bromobutyric acid (BBA) was developed in this study. This probe enhances water/oxygen stability and addresses the limitation that restricts the application of perovskite quantum dots as fluorescent probes. The probe was used to stain intraoperative tumor frozen sections to verify its specific recognition capability for IDH1-mutant glioma. RESULTS: Verification using 50 glioma frozen sections demonstrated that the probe could accomplish rapid pathological detection within 30 min (with a 5-minute incubation period). Fluorescence imaging showed specific green fluorescence in IDH1-mutant glioma. When compared with genetic testing results, the probe exhibited the following detection performance: sensitivity of 100%, specificity of 84%, positive predictive value of 86.2%, negative predictive value of 100%, and accuracy of 92% (κ = 0.84, P < 0.001). CONCLUSIONS: This BBA-stabilized perovskite probe enables rapid and specific in vitro detection of IDH1-mutant glioma. It provides real-time guidance for glioma surgery, is expected to assist surgeons in achieving precise resection of glioma, and thus advances the development of precision neuro-oncology.
Alpha-synuclein (α-Syn) is a neuronal protein implicated in the pathogenesis of several neurodegenerative disorders collectively known as synucleinopathies, including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. This article provides a comprehensive overview of the structural characteristics of α-Syn, emphasizing its fibrillar aggregation and the resulting polymorphic fibril forms. Using advances in cryo-electron microscopy, a diverse range of α-Syn fibril polymorphs has been elucidated, both from in vitro preparations and patient-derived brain samples. We further explore the impact of mutation and post-translational modifications-such as truncation and phosphorylation -on α-Syn structure and the unique polymorphs they induce. The article underscores the biological and pathological relevance of α-Syn polymorphism, highlighting how different structural strains may underlie the structural and pathological heterogeneity observed in synucleinopathies. Understanding the mechanisms driving polymorph formation is critical for deciphering disease progression and developing targeted therapeutic strategies.
Endothelial-to-mesenchymal transition (EndMT) is a phenotypic switch in which endothelial cells acquire mesenchymal characteristics, involving both functional and morphological changes. While EndMT is essential for cardiac development, its aberrant activation contributes to adult cardiovascular pathologies, including calcific aortic valve disease (CAVD). Dysregulation of ectonucleotidases-membrane-bound enzymes that regulate extracellular ATP and adenosine metabolism-has been implicated in such diseases. Altered extracellular nucleotide signaling influences valvular interstitial cell (VIC) degeneration and may interact with valvular endothelial cells (VECs) undergoing EndMT. The objective of this study was to investigate the role of the purinergic signaling system in regulating EndMT in human aortic VECs. Primary human VECs were cultured in vitro and treated with inhibitors of ectonucleoside triphosphate diphosphohydrolase 1 (CD39), ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), and 5'-nucleotidase (CD73), alongside adenosine and P2 purinergic receptor agonists. EndMT markers and signaling pathways were assessed via phosphorylation assays and mRNA expression analysis of key transcription factors, including SLUG, SNAIL, ZEB1, and ZEB2. Inhibition of ATP- and AMP-hydrolyzing enzymes (CD39, ENPP1, CD73) enhanced p38 phosphorylation and modulated SLUG expression. Activation of P2 and adenosine A2B receptors altered SNAIL levels, while A2A receptor signaling influenced ZEB1 and ZEB2 expression. These perturbations resulted in pronounced morphological changes consistent with EndMT. In conclusion, dysregulation of the purinergic signaling system induces EndMT in human aortic VECs, highlighting a potential mechanistic link between extracellular nucleotide metabolism and valvular pathology. Targeting purinergic pathways may represent a therapeutic avenue for CAVD and related vascular disorders.
While gefitinib greatly improves the prognosis of lung cancer patients with epidermal growth factor receptor (EGFR) mutation, its inevitable resistance severely diminishes therapeutic efficacy. Cell migration-inducing protein (CEMIP) might interact with cellular MYC proto-oncogene (c-MYC) to synergistically drive gefitinib resistance. However, the mechanism by which CEMIP/c-MYC regulates gefitinib resistance in LUAD remains unknown. The gefitinib-acquired resistance (AR) cell line PC9GR was established by gradual dose-escalation induction. CEMIP expression was up-regulated in PC9GR cells, suggesting the positive corelationship might exsit between CEMIP expression and gefitinib resistance. Similarly, overexpressing CEMIP in PC9 cells not only increased IC50 value of gefitinib but also enhanced the proliferation, migration and tolerance to gefitinib. In contrast, downregulating the expression of CEMIP in PC9GR cells partially restored gefitinib sensitivity and reduced malignant phenotypes. Furthermore, c-MYC promoted transcriptional activity through binding to the promoter region of CEMIP. Rescue assays demonstrated that reducing the expression of c-MYC downregulated the IC50 value of Gefitinib, migration and tolerance of gefitinib in PC9 OE cells, while overexpressing c-MYC reversed these malignant phenotypes in PC9GR shCEMIP cells. Subcutaneous xenograft model also supported that the expression of CEMIP positively correlated to c-MYC in tumor tissues. Mechanistically, protein docking simulations and Co-IP assays indicated that CEMIP directly interacted with c-MYC via its 1-177aa domain to form the CEMIP/c-MYC complex. Furthermore, CHX chase assays showed that CEMIP and c-MYC mutually stabilized the expression of both proteins. The elevated CEMIP/c-MYC axis accelerates EMT to enhance cell migration, thereby contributing to the acquisition of gefitinib resistance in LUAD.
Given that extracellular vesicles (EVs) secreted from stem cells contain angiogenic microRNAs (miRNAs), these EVs show equivalent angiogenic therapeutic effect to cell transplantation. This study aimed to identify the angiogenic miRNAs from several miRNAs involved in EVs secreted from stem cells. In human dental pulp stem cells (hDPSCs) under hypoxic culture, vascular endothelial growth factor (VEGF) involved in EVs increased. We hypothesized that angiogenic miRNAs increase in EVs that are secreted from hDPSCs under hypoxic culture compared with those under normoxic culture. In the first screening, the expression levels of miRNAs involved in EVs that were secreted from hDPSCs cultured under hypoxic and normoxic conditions were analyzed using miRNA array. In the second screening, 12 miRNAs were individually involved in EVs, and the growth of human aortic endothelial cells was assayed. In the third screening, miRNA-encapsulated EVs were injected in BALB/c mouse hindlimb ischemia model, followed by angiogenesis evaluation by blood flow analysis. Results showed that miR-765 is an angiogenic miRNA, targeting the 3' untranslated region of dipeptidyl peptidase 4 (DPP4) and upregulating fibroblast growth factor 2 (FGF2) in vitro and in vivo. In conclusion, as an angiogenesis mechanism, miR-765 increased FGF2 expression levels by inhibiting DPP4.
Orofacial pain is difficult to manage. Treatments like nonsteroidal anti-inflammatory drugs (NSAIDs), and serotonin agonists provide limited relief or produce side effects. These limitations highlight the need for alternative strategies that reduce orofacial pain without adverse effects. One approach is polypharmacology, where a single compound modulates multiple targets involved in pain. Fatty acid amide hydrolase (FAAH) and soluble epoxide hydrolase (sEH) are regulators of pain that can be targeted simultaneously to enhance antinociceptive efficacy. We previously reported that the 4-phenylthiazole-based dual FAAH/sEH inhibitor SW-17 does not alleviate acute orofacial pain in rats, and it showed low stability in rat liver microsomes. We introduced electronic and steric modifications to the thiazole and phenyl rings of the 4-phenylthiazole scaffold to improve the stability and better understand structure-activity relationship of this set of analogs. An 11-compound library was synthesized by varying alkyl groups at position 5 of the thiazole ring and substituents on the phenyl ring. Several analogs exhibited nanomolar potency at both enzymes. The most potent compound, 4j, exhibited IC50 values of 18.7 nM and 25.1 nM for human FAAH and sEH, respectively. 4j was evaluated in rat liver microsomes where it exhibited relatively low metabolic stability but better than SW-17. ADMET studies indicated that 4j possesses promising safety features. At 3 mg/kg, 4j reversed acute orofacial inflammatory pain, whereas SW-17 was ineffective. This effect was comparable to sumatriptan and did not reduce voluntary wheel running. These findings imply that optimized dual FAAH/sEH inhibitors can alleviate orofacial pain without affecting normal behavior.
Glaucoma is the second leading cause of irreversible blindness globally, with elevated intraocular pressure (IOP) being its primary risk factor. Current therapeutic approaches, such as beta-blockers, alpha-adrenergic agonists, Rho-kinase inhibitors, etc., aim to reduce IOP levels. However, the molecular mechanisms underlying altered IOP remain poorly understood. In this study, we have treated primary human trabecular meshwork cells (HTM) with exogenous dexamethasone (dex) or transforming growth factor beta-2 (TGF-β2) to investigate their effects on glaucoma candidate genes. Interestingly, our findings reveal that FOXC1 acts as a repressor of CYP1B1, and optineurin (OPTN) facilitates the ubiquitination of FOXC1, thereby inducing the expression of CYP1B1. Furthermore, we found that the miR-200 family and other miRNAs regulate these glaucoma candidate genes. Furthermore, TGF-β2 downregulates the miR-200 family, whereas the miR-200 family targets FOXC1, exerting reversible effects by altering the extracellular matrix. Thus, modulating the TGF-β2/OPTN/FOXC1/miR-200 axis appears critical in regulating actin dynamics in the anterior eye segment.
Receptor activator of NF-κB ligand (RANKL) produced by osteoblastic lineage cells is essential for osteoclastogenesis, yet RANKL can be sequestered in intracellular, lysosome-like compartments under basal conditions. How mechanical cues mobilize RANKL toward the cell surface remains poorly defined. Here, we tested whether fluid shear stress alters RANKL subcellular distribution in osteoblast-like MC3T3-E1 cells and examined the involvement of the non-receptor tyrosine kinase c-Src. MC3T3-E1 cells expressing fluorescently tagged RANKL were subjected to fluid shear stress, and RANKL localization was analyzed by microscopy and subcellular fractionation. Fluid shear stress increased c-Src activation (Tyr416 phosphorylation) and promoted redistribution of RANKL toward the cell periphery, accompanied by an increase of RANKL in the membrane fraction. Co-expression experiments showed spatial association of RANKL with c-Src at the cell periphery after shear stimulation. Moreover, constitutively active c-Src (Y527F) enhanced peripheral localization of RANKL even in the absence of shear stress. Together, these data support a model in which shear stress activates c-Src to facilitate RANKL localization from intracellular stores toward membrane-proximal regions, thereby providing a mechanistic link between mechanical cues and osteoblast-derived osteoclastogenic signaling.
Antimicrobial peptides (AMPs) are essential components of the innate immune system and have emerged as promising candidates against antibiotic-resistant infections. Beyond their antimicrobial activity, AMPs also play a crucial role in regulating tissue regeneration processes, including wound healing. Previous studies have shown that the frog skin-derived AMP, esculentin-1a(1-21) [Esc(1-21)], promotes wound healing by accelerating keratinocyte migration. Its derivative, esculentin-1a(1-21)-1c [Esc(1-21)-1c] has proven even more effective in facilitating wound closure in alveolar and bronchial epithelial cell monolayers. Given the essential role of dermal fibroblasts in skin regeneration, this study aimed to investigate the effects of Esc(1-21) and its two derivatives, Esc(1-21)-1c and [Aib8]-Esc(1-21) (containing the non-natural α-aminoisobutyric acid at position 8), on the activation of human primary dermal fibroblasts (hDFs) during the healing of a pseudo-wound. The results demonstrated that all three peptides significantly enhanced hDFs migration and stimulated wound closure by activating the MAPK/ERK signaling pathway, without affecting cell proliferation. Importantly, for Esc(1-21) and [Aib8]-Esc(1-21), this activation was clearly mediated by Epidermal Growth Factor Receptor (EGFR). Finally, the peptides upregulated the expression of early wound healing markers, such as Collagen I and Collagen III, but did not alter the expression of late-stage markers, including MMP9 and α-SMA. These findings highlight the regenerative potential of Esc(1-21) and its derivatives and suggest their relevance in therapeutic strategies for impaired wound healing.
Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) are a valuable tool for modeling cardiac diseases, drug testing, and regenerative applications. However, their application is limited by the immature phenotype of iPSC-CM. During maturation from fetal to adult phenotype cardiomyocytes undergo a transition from glycolysis to oxidative phosphorylation for energy production, which is supported by efficient tricarboxylic acid (TCA) cycle activity. Our metabolomics data suggest that the level of intermediates of TCA cycle including succinate, malate, fumarate, and α-ketoglutarate was very low in iPSC-CM. Therefore, we investigated the effect of supplementation with these metabolites on the maturation of iPSC-CM. We cultured iPSC-CM in glucose (Glu), galactose (Gal), or galactose plus TCA cycle intermediates (Gal+TCA) and evaluated the incremental effect of TCA cycle intermediates supplementation relative to Glu and Gal. The treatment with these TCA cycle intermediates led to improved calcium handling and cellular morphology of iPSC-CM relative to Glu and Gal. Furthermore, the treatment with TCA cycle metabolites enhanced electrical activity, improved mitochondrial health, and the cells were shifting toward oxidative phosphorylation relative to Glu only. This shift in the energy metabolism was associated with an upregulation in the expression of cardiomyocyte maturation genes and downregulation in the expression of fetal genes in Gal + TCA group relative to Glu. Overall, the benefits of Gal+TCA supplementation were quite evident compared to Glu alone but generally modest relative to Gal supplementation, supporting that TCA cycle intermediates supplementation can be used as an adjunct strategy to promote iPSC-CM maturation.
Glycoinformatics has entered the artificial intelligence era. Stymied by a lack of big data, high sequence complexity, and biosynthetic dependencies, the application of machine learning to glycomics data has largely emerged this decade. In this mini-review, we explore the latest groundbreaking computational approaches applied to glycan sequencing, classifying disease risk from glycan biomarkers, and predicting protein-glycan interactions. We detail advancements in the architectures of these models, concluding that they have matured to the stage of extracting predictive information from glycan sequences. We also discuss their challenges and limitations, and how to fully reap their rewards in the future.
A theoretical model of mitochondrial β-oxidation efficiency is presented, using ATP yield per oxygen atom (P:Oβ-ox) as a proxy for performance under oxygen-limited conditions. Expressed as a function of chain length and unsaturation, the model generates hyperbolic efficiency surfaces whose maxima mirrors the natural abundance of fatty acids in adipose tissues. It predicts a crossover near d ≈ 1.6, where efficiency becomes chain-length-independent-thus matching the dominance of monounsaturated FAs in mammals. The model aligns with empirical mobilization patterns and suggests an oxygen- and ATP-sensitive regulatory axis shaping lipid profiles in hypoxic or energy-stressed states.
Pathogenic variants in the GNAO1 gene, which encodes for Gαo, a major neuronal G protein, are associated with neurodevelopmental disorders, epilepsy, and movement disorders. We identified and characterized in detail a de novo heterozygous GNAO1 E246K pathogenic variant in an Israeli female infant with complex developmental delay and substantial motor difficulties. This variant has been reported in other cases as a recurrent pathogenic variant in patients with motor dysfunction and a broad range of neurological outcomes. To investigate the molecular and functional consequences of the Gαo E246K variant, we employed structural modeling and analysis, mass spectrometry-based proteomics, biochemical assays, and cellular functional assays. Our biochemical results show that this variant does not affect nucleotide binding, nor basal or RGS-accelerated GTP hydrolysis. Despite the E246 position location within a predicted effector binding region, mass spectrometry analysis did not identify any novel cellular partners. Instead, we demonstrate that the E246K variant disrupts the Gαo regulatory GTPase cycle by directly impairing Gβγ dissociation. This impairment overrides the function of wild-type Gαo, explaining the dominant effect and the severity of the neurogenetic phenotype despite a heterozygous background. These findings establish a new molecular mechanism for a GNAO1 variant with dominant-negative effects on the GTPase regulatory cycle. The insights gained from studying this mechanism of action provide a basis for developing specific and personalized therapeutic strategies based on the outcome of a missense mutation in GNAO1.
Angiotensin II Receptor-Associated Protein (AGTRAP) is markedly overexpressed in hepatocellular carcinoma (HCC) cases associated with poor prognosis; however, its precise functional role remains inadequately elucidated. This study aimed to elucidate the functional role of AGTRAP in HCC progression and its impact on the tumor microenvironment (TME). We knocked down AGTRAP expression in HCC cell lines (HepG2 and SK-hep1) using shRNA and evaluated the impact of AGTRAP knockdown on hepatocellular carcinoma cells through proliferation, invasion, and migration. Immunofluorescence staining was used to analyze the distribution of M1-type and M2-type macrophages in HCC patient tissues. The signaling pathway mechanism by which AGTRAP regulates macrophage polarization was further analyzed, focusing on the p38 MAPK pathway. The effects and mechanisms of exosomes derived from AGTRAP-knockdown HCC cells on macrophage polarization were investigated. Silencing AGTRAP significantly enhanced apoptosis, disrupted cell cycle progression, and diminished the invasive and migratory capacities of HCC cells.Tumors with high AGTRAP expression exhibited increased M2-type macrophages and decreased M1-type macrophages, indicating a shift in the TME towards an immunosuppressive state.Mechanistic studies revealed that AGTRAP modulates macrophage polarization by interacting with the p38 MAPK signaling pathway.Exosomes derived from AGTRAP-silenced HCC cells also influenced macrophage polarization via the p38 MAPK pathway. AGTRAP facilitates HCC progression by mediating exosomal communication between cancer cells and macrophages via the p38 MAPK pathway, underscoring its pivotal role in shaping the immunosuppressive tumor microenvironment.
S100A13, a calcium-binding protein containing two EF-hand motifs, contributes to intracellular calcium homeostasis, a key determinant of mitochondrial quality control. We previously showed that S100A13 modulates mitochondrial membrane potential (ΔΨm) in patient-derived skin fibroblasts carrying S100A13 (p.I80Gfs*13) and S100A3 (p.R77C) mutations. However, its role in regulating mitochondrial dynamics remains unclear. Here, we investigated whether S100A13 regulates mitochondrial fusion-fission balance in human bronchial epithelial cells (BEAS-2B) using Myc-tagged wild-type or p.I80Gfs*13 S100A13 constructs. The S100A13 p.I80Gfs*13 mutant markedly attenuated bradykinin- and ionophore-induced intracellular calcium transients and reduced ΔΨm compared with wild-type S100A13 (p < 0.05). These alterations were associated with severe mitochondrial ultrastructural abnormalities, disrupted cristae organization, and increased mitochondrial fragmentation (p < 0.05). Interestingly, both wild-type and p.I80Gfs*13 mutant S100A13 increased expression of the mitochondrial fusion-associated proteins MFN1/2 and OPA1 while reducing expression of the fission mediator MFF. However, despite these apparently pro-fusion molecular changes, the S100A13 p.I80Gfs*13 mutant failed to maintain mitochondrial fusion competency, suggesting a functional uncoupling between fusion protein abundance and mitochondrial fusion competency. Collectively, these findings identify S100A13 as an important regulator of intracellular calcium-dependent mitochondrial dynamics and demonstrate that C-terminal truncation disrupts calcium-dependent regulation of mitochondrial fusion and cristae integrity in lung epithelial cells.