This experimental review discusses evolutionarily approved, naturally pre-designed skeletal architectures of marine keratosan sponges in the form of 3D scaffolds, which have garnered increasing interest in the fields of structural and functional biomimetics as well as in tissue engineering. It has been demonstrated that these renewable, ready-to-use natural scaffolds can undergo further modifications through specialized treatments such as metallization and carbonization, enabling the creation of functional biomaterials while maintaining the species-specific hierarchical 3D structure. The study presented remarkable findings, including the demonstration of the unique shape-memory behavior of these scaffolds even after two months of exposure to high mechanical pressure at temperatures exceeding 100 °C. Additionally, the cytocompatibility and biological performance of natural and carbonized (1200 °C) spongin scaffolds, derived from selected bath sponges, were comparatively investigated with respect to growth and proliferation of human MG-63 osteoblastic cells. Understanding whether carbonization universally enhances osteogenic capabilities or selectively amplifies the inherent architectural advantages remains to be critical for the rational design of sponge-derived scaffolds in bone and structural tissue engineering applications.

Becker Muscular Dystrophy (BMD) is caused by in-frame mutations in the DMD gene, leading to the production of internally truncated but partially functional dystrophin. Although cardiac involvement is a major contributor to disease burden in BMD, the cellular mechanisms driving cardiomyopathy remain incompletely understood. While emerging evidence suggests that iron imbalance may contribute to oxidative stress and mitochondrial dysfunction in muscular dystrophies, its role in BMD-associated cardiomyopathy has not been defined. Building on our previous findings of dysregulated iron homeostasis in dystrophin-deficient cardiomyocytes from Duchenne muscular dystrophy (DMD), we investigated whether similar alterations are present in BMD using patient-specific and genome-corrected hiPSC-CM models. HiPSC lines derived from two BMD patients and their CRISPR/Cas9-corrected isogenic controls displayed normal karyotype, pluripotency, and efficient differentiation into cardiomyocytes (hiPSC-CMs). BMD hiPSC-CMs showed elevated ROS levels and decreased cytoplasmic and mitochondrial labile iron pools, accompanied by reduced expression of mitoNEET ( CISD1 ), a regulator of mitochondrial iron handling. We also detected changes in the expression of genes involved in iron storage ( FTH1 ), uptake ( TFRC ), and export ( SLC40A1 ), suggesting a dysregulation of iron trafficking. Importantly, correction of DMD mutation by CRISPR/Cas9 gene editing reversed the effects observed in BMD cardiomyocytes. These results extend our previous observations in DMD to BMD cardiomyocytes and suggest that full-length dystrophin is essential for maintaining cardiac iron homeostasis.

Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by muscle weakness. It causes movement issues and severe physical disability. SMA is classified into four types based on the level of function achieved, age of onset, and maximum function achieved. The deletion or point mutation in the Survival of Motor Neuron 1 ( SMN1 ) gene causes SMA. As a result, no full-length protein is produced. A nearly identical paralog, SMN2, provides enough stable protein to prevent death but not enough to compensate for SMN1's loss. The difference between SMN1 and SMN2 is due to different exon 7 alternative splicing patterns. SMA molecular therapies currently focus on restoring functional SMN protein by splicing modification of SMN2 exon 7 or elevated SMN protein levels. Nusinersen, an antisense oligonucleotide targeting the ISS-N1 sequence in SMN2 intron 7, was the first drug approved by the Food and Drug Administration. Risdiplam, a novel therapeutic that acts as an SMN2 exon 7 splicing modifier, was recently approved. All of these drugs result in the inclusion of SMN2 exon 7, and thus the production of functional SMN protein. Onasemnogene abeparvovec is a gene therapy that uses a recombinant adeno-associated virus that encodes the SMN protein. There are also experimental therapies available, such as reldesemtiv and apitegromab (SRK-015), which focus on improving muscle function or increasing muscle tissue growth, respectively. Although approved therapies have been shown to be effective, not all SMA patients can benefit from them due to age or weight, but primarily due to their high cost. This demonstrates the significance of continuous treatment improvement in today's medical challenges.

Naturally pre-structured three-dimensional (3D) scaffolds derived from commercial marine sponges represent renewable biomaterials with hierarchical, porous architecture optimized by evolution. For the first time, purified spongin scaffolds from Hippospongia communis sponges were functionalized via ion–plasma vacuum arc deposition of titanium, followed by high-temperature carbonization. The applied metallization process preserved the native open-cell 3D architecture of spongin while introducing an α-Ti nanostructured surface layer. Subsequent carbonization at 1200 °C led to the formation of turbostratic carbon and crystalline titanium carbide/oxycarbide phases, as confirmed by SEM, EDX, HRTEM, XRD, and Raman spectroscopy. The biological response of MG-63 osteoblast-like cells was evaluated using indirect cytocompatibility screening, Live/Dead confocal microscopy, WST-1 metabolic activity analysis, protein-normalized ALP-associated activity, and immunofluorescence staining of osteoblast- and adhesion-associated markers. MG-63 cells were selected to provide a bone-relevant osteoblast-like in vitro model for assessing cell–material interactions on Ti-containing spongin-based scaffolds. Ti–Spg and C–Ti–Spg scaffolds demonstrated enhanced cell coverage after 7 days of culture compared with native spongin. At day 14, C–Ti–Spg showed the highest protein-normalized ALP-associated activity together with the most extensive RUNX2-, OPN- and FAK-associated immunostaining pattern, supporting enhanced osteoblast-related activity and adhesion/matrix-associated cell–scaffold interactions under basal culture conditions. Complementary WST-1 metabolic readouts and FDA/PI confocal imaging did not indicate material-induced cytotoxicity, while WST-1 data were interpreted as relative metabolic indicators because colorimetric assays in 3D porous scaffolds can be influenced by reagent diffusion and scaffold architecture. This study demonstrates that naturally prefabricated 3D spongin scaffolds can be successfully metallized with Ti and converted into TiC-containing carbonized composites without loss of structural integrity or cytocompatibility. The combination of preserved hierarchical architecture with titanium-based surface chemistry provides a sustainable platform for the further development of bioinspired functional scaffolds for tissue engineering applications. Graphical abstract

BACKGROUND: Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular disease caused by mutations in the DMD gene, leading to the absence or dysfunction of dystrophin. Although cardiac and skeletal muscles are both affected, tissue-specific differences in disease manifestation and dystrophin regulation remain poorly understood. METHODS: To investigate these differences, we established a human induced pluripotent stem cell model of DMD from peripheral blood mononuclear cells of a patient (DMD patient with a point mutation in intron 68 (c.9975-1G>T) investigated in the study [DMB15]) carrying a splice-site mutation in intron 68 (c.9975-1G>T). An isogenic control line was generated via clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats–associated protein 9 (CRIPSR/Cas9) correction. Both repaired and DMD human induced pluripotent stem cells were differentiated into cardiomyocytes (DMB15-CMs) and skeletal muscle cells (DMB15-derived skeletal muscle cells); the skeletal muscle lineage included a myoblast (DMB15-derived myoblasts) stage. Transcript and protein analyses were performed, along with functional assessments using microelectrode array recordings and calcium handling analysis. RESULTS: Transcript analysis revealed an in-frame deletion of 2 amino acids (Tyr3325 and Arg3326) due to skipping of the first 6 nucleotides of exon 69. Despite this, near full-length Dp427 (full-length dystrophin isoform of 427 kDa) was detected by Western blot, along with expression of Dp116 (dystrophin isoform of 116 kDa) in DMB15-CMs. Dystrophin levels were preserved in DMD DMB15-CMs but markedly reduced in DMB15-derived skeletal muscle cells, suggesting tissue-specific regulation. Analysis of DMB15-derived myoblasts demonstrated possible changes in myogenic program activation, alongside inconsistent expression of utrophin, the dystrophin paralogue. Functional analysis showed altered β-adrenergic responsiveness in DMD DMB15-CMs, with increased beating frequency and accelerated repolarization on isoproterenol stimulation. DMB15-CMs showed largely preserved basal Ca ²⁺ cycling but failed to maintain a normal amplitude response under β-adrenergic stimulation. CONCLUSIONS: Our study identifies a splice-site DMD gene mutation that preserves high levels of dystrophin expression in cardiac muscle but reduced in skeletal muscle and reveals Dp116 expression in cardiomyocytes. These findings highlight the importance of tissue context in DMD and demonstrate the power of human induced pluripotent stem cell–based systems for dissecting mutation-specific effects.

Background: Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular disease caused by mutations in the DMD gene, leading to the absence or dysfunction of dystrophin. While cardiac and skeletal muscles are both affected, tissue-specific differences in disease manifestation and dystrophin regulation remain poorly understood. Methods: To investigate these differences, we established a human induced pluripotent stem cell (hiPSC) model of DMD from peripheral blood mononuclear cells (PBMC) of a patient carrying a splice-site mutation in intron 68 (c.9975-1G>T). An isogenic control line was generated via CRISPR/Cas9 correction. Both repaired and DMD hiPSCs were differentiated into cardiomyocytes (hiPSC-CMs) and skeletal muscle cells (hiPSC-SMs). Transcript and protein analyses were performed, along with functional assessment using microelectrode array. Results: Transcript analysis revealed an in-frame deletion of two amino acids (Tyr3325 and Arg3326) due to skipping of the first six nucleotides of exon 69. Despite this, near full-length Dp427 was detected by western blot, along with expression of Dp116 in hiPSC-CMs. Dystrophin levels were preserved in DMD hiPSC-CMs but markedly reduced in hiPSC-SMs, suggesting tissue-specific regulation. Functional analysis showed altered β-adrenergic responsiveness in DMD hiPSC-CMs, with increased beating frequency and accelerated repolarization upon isoproterenol stimulation. Conclusions: Our study identifies a splice-site mutation that preserves high level of dystrophin expression in cardiac but reduced in skeletal muscle and reveals Dp116 expression in cardiomyocytes. These findings highlight the importance of tissue context in DMD and demonstrate the power of hiPSC-based systems for dissecting mutation-specific effects.