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Henry J Kaminski

Publications and source records attributed to Henry J Kaminski.

At least 19 recordsLinked to original sources
PubMed2026

Proteomic and machine learning analysis predicts treatment response signatures in Myasthenia Gravis.

BACKGROUND: Myasthenia gravis (MG) is a prototypical antibody-mediated autoimmune disease with variable treatment responses with a need for biomarkers to guide therapeutic decision making. Proteomic profiling, coupled with machine learning, offers a hypothesis-free approach to identify multi-protein signatures associated with treatment response. METHODS: We analyzed sera collected at entry (baseline) from participants in a phase 3 trial randomized trial comparing thymectomy plus prednisone versus prednisone alone, along with matched controls using liquid chromatography-mass spectrometry. We derived disease-specific proteomic signatures and evaluated associations between baseline proteins and 6-month clinical outcomes using multiple machine-learning approaches with internal validation. RESULTS: Baseline serum proteomes distinguished MG from controls, with pathway enrichment implicating complement activation, immunoglobulin production, and T-cell receptor signaling. Distinct protein panels predicted 6-month clinical improvement within each treatment arm. In the thymectomy-plus-prednisone group, models captured non-linear relationships of predictive proteins in contrast with the predominant additive patterns observed in the prednisone-alone group. Predictive proteins were enriched for T-cell signaling and leukocyte trafficking functions, providing insight into treatment-specific biology. CONCLUSIONS: Baseline serum proteomics captures core disease characteristics of MG and predicts short-term clinical response in a treatment-specific manner. While our results require validation in independent cohorts, these findings could enable biomarker-guided selection of thymectomy, refine risk stratification, and furnish mechanistic readouts for future MG trials and clinical care. We aim to conduct future studies using -omic approaches to validate these baseline predictive biomarkers and pathways of treatment response in patients with MG.

Adult↗
PubMed2006

Deficiency of decay accelerating factor and CD59 leads to crisis in experimental myasthenia.

In myasthenia gravis (MG), neuromuscular transmission is disrupted due to the production of autoantibodies against acetylcholine receptors (AChR). In previous work, we showed that decay accelerating factor (DAF or CD55), an intrinsic cell surface complement regulator that disables C3/C5 amplification convertases, protects against receptor loss and muscle weakness. In this study, we examined whether, and if so, to what extent CD59, a downstream intrinsic cell surface regulator that prevents assembly of membrane attack complexes (MACs), contributes to this protection. Twenty-four hours after anti-AChR injection, we found that CD59a-/- mice did not significantly differ from WTs, all Daf1-/- CD59a-/- mice either died or required euthanasia. At 48h, Daf1-/- were significantly weaker than CD59a-/- and WT mice, and for these mice immunohistochemistry revealed marked C9 deposition at postsynaptic junctions, radioimmunoassays showed reductions in AChR levels, and electron microscopy demonstrated massive junctional damage. These data indicate that DAF serves as the initial shield that protects the neuromuscular junction whereas CD59 is a further barrier. They argue that complement inhibitor, particularly if targeted to the receptor, could then have therapeutic value in human MG.

Analysis of Variance↗
PubMed2006

A genetic model for muscle-eye-brain disease in mice lacking protein O-mannose 1,2-N-acetylglucosaminyltransferase (POMGnT1).

Protein O-mannose beta1,2-N-acetyglucosaminyltransferase 1 (POMGnT1) is an enzyme involved in the synthesis of O-mannosyl glycans. Mutations of POMGnT1 in humans result in the muscle-eye-brain (MEB) disease. In this study, we have characterized a null mutation generated by gene trapping with a retroviral vector inserted into the second exon of the mouse POMGnT1 locus. Expression of POMGnT1 mRNA was abolished in mutant mice. Glycosylation of alpha-dystroglycan was also reduced. POMGnT1 mutant mice were viable with multiple developmental defects in muscle, eye, and brain, similar to the phenotypes observed in human MEB disease. The present study provides the first genetic animal model to further dissect the roles of POMGnT1 in MEB disease.

Animals↗
PubMed2006

Molecular architecture of the neuromuscular junction.

The neuromuscular junction (NMJ) is a complex structure that serves to efficiently communicate the electrical impulse from the motor neuron to the skeletal muscle to signal contraction. Over the last 200 years, technological advances in microscopy allowed visualization of the existence of a gap between the motor neuron and skeletal muscle that necessitated the existence of a messenger, which proved to be acetylcholine. Ultrastructural analysis identified vesicles in the presynaptic nerve terminal, which provided a beautiful structural correlate for the quantal nature of neuromuscular transmission, and the imaging of synaptic folds on the muscle surface demonstrated that specializations of the underlying protein scaffold were required. Molecular analysis in the last 20 years has confirmed the preferential expression of synaptic proteins, which is guided by a precise developmental program and maintained by signals from nerve. Although often overlooked, the Schwann cell that caps the NMJ and the basal lamina is proving to be critical in maintenance of the junction. Genetic and autoimmune disorders are known that compromise neuromuscular transmission and provide further insights into the complexities of NMJ function as well as the subtle differences that exist among NMJ that may underlie the differential susceptibility of muscle groups to neuromuscular transmission diseases. In this review we summarize the synaptic physiology, architecture, and variations in synaptic structure among muscle types. The important roles of specific signaling pathways involved in NMJ development and acetylcholine receptor (AChR) clustering are reviewed. Finally, genetic and autoimmune disorders and their effects on NMJ architecture and neuromuscular transmission are examined.

Animals↗
PubMed2006

Ocular myasthenia: diagnosis, treatment, and pathogenesis.

BACKGROUND: Although myasthenia gravis (MG) is often considered the best-understood autoimmune disorder and effective treatments have controlled life-threatening complications, the pathogenesis of ocular myasthenia (OM) remains enigmatic, and its clinical consequences offer therapeutic challenges. REVIEW SUMMARY: About half of patients with MG present with visual complaints of droopy eyelids or double vision, and many will remain with purely ocular muscle weakness without generalized weakness, defined as OM. OM may be confused with disorders of the brainstem, ocular motor nerves, and eye muscles. Frustrating for the clinician, confirmatory tests such as the edrophonium test, serum acetylcholine receptor antibodies, and standard electrodiagnostic evaluations may fail to positively identify the clinical suspicion of OM. Patients may derive relief from nonpharmacologic interventions and cholinesterase inhibitors, but most will desire better symptom control with corticosteroids or need other immunosuppression. Early corticosteroid therapy may reduce the probability of generalization of the disease. The reasons for ocular muscle involvement by OM include physiologic and cellular properties of the ocular motor system and the unique immunology of OM, which, when better understood, will lead to novel treatments. CONCLUSIONS: OM is a challenging disorder for the clinician and scientist, with both learning from the other for the betterment of the patient. The future requires answers to why the ocular muscles are so frequently involved by MG, whether the generalization of the disease may be limited by early corticosteroid treatment, and what treatment options may be developed which will improve symptoms without long-term complications.

Humans↗
PubMed2006

Myasthenia gravis: past, present, and future.

Myasthenia gravis (MG) is an autoimmune syndrome caused by the failure of neuromuscular transmission, which results from the binding of autoantibodies to proteins involved in signaling at the neuromuscular junction (NMJ). These proteins include the nicotinic AChR or, less frequently, a muscle-specific tyrosine kinase (MuSK) involved in AChR clustering. Much is known about the mechanisms that maintain self tolerance and modulate anti-AChR Ab synthesis, AChR clustering, and AChR function as well as those that cause neuromuscular transmission failure upon Ab binding. This insight has led to the development of improved diagnostic methods and to the design of specific immunosuppressive or immunomodulatory treatments.

Animals↗
PubMed2005

Temporal and spatial mRNA expression patterns of TGF-beta1, 2, 3 and TbetaRI, II, III in skeletal muscles of mdx mice.

To address potential regulatory roles of TGF-beta1 in muscle inflammation and fibrosis associated with dystrophin deficiency, we performed quantitative RT-PCR and in situ hybridization to characterize the temporal and spatial mRNA expression patterns of TGF-beta1 and other TGF-beta subfamily members, TGF-beta2 and TGF-beta3, as well as their receptors, in quadriceps and diaphragm muscles of mdx mice. TGF-beta1 mRNA was markedly upregulated in the endomysial inflammatory cells and regenerating fibers of mdx quadriceps and diaphragm, with the mRNA levels correlated with the degree of endomysial inflammation. Upregulation of TGF-beta2, beta3, and their receptors was also appreciated but to a much lesser degree. While high levels of TGF-beta1 mRNA remained in the aging mdx quadriceps but not the diaphragm, progressive fibrosis only occurred in the diaphragm. Our data support a regulatory role for TGF-beta1 in muscle inflammation in mdx mice. It also suggests different susceptibility of quadriceps and diaphragm muscles to fibrosis induced by TGF-beta1 signaling pathway.

Animals↗
PubMed2005

Distinctive morphological and gene/protein expression signatures during myogenesis in novel cell lines from extraocular and hindlimb muscle.

Skeletal muscles are not created equal. The underutilized concept of muscle allotypes defines distinct muscle groups that differ in their intrinsic capacity to express novel traits when exposed to a facilitating extrinsic environment. Allotype-specific traits may have significance as determinants of the preferential involvement or sparing of muscle groups that is observed in a variety of neuromuscular diseases. Little is known, however, of the developmental mechanisms underlying the distinctive skeletal muscle allotypes. The lack of appropriate in vitro models, to dissociate the cell-autonomous and non-cell-autonomous mechanisms behind allotype diversity, has been a barrier to such studies. Here, we derived novel cell lines from the extraocular and hindlimb muscle allotypes and assessed their similarities and differences during early myogenesis using morphological and gene/protein expression profiling tools. Our data establish that there are fundamental differences in the transcriptional and cellular signaling pathways used by the two myoblast lineages. Taken together, these data show that myoblast lineage plays a significant role in the divergence of the distinctive muscle groups or allotypes.

Animals↗
PubMed2004

Adverse effects of myasthenia gravis on rat phrenic diaphragm contractile performance.

Myasthenia gravis has variable effects on the respiratory system, ranging from no abnormalities to life-threatening respiratory failure. Studies characterized diaphragm muscle contractile performance in rat autoimmune myasthenia gravis. Rats received monoclonal antibody that recognizes acetylcholine receptor determinants (or inactive antibody); 3 days later, phrenic nerve and diaphragm were studied in vitro. Myasthenic rats segregated into two groups, those with normal vs. impaired limb muscle function when tested in intact animals ("mild" and "severe" myasthenic). Baseline diaphragm twitch force was reduced for both severe (P < 0.01) and mild (P < 0.05) myasthenic compared with control animals (twitch force: normal 1,352 +/- 140, mild myasthenic 672 +/- 99, severe myasthenic 687 +/- 74 g/cm2). However, only severe myasthenic diaphragm had impaired diaphragm endurance, based on significantly (P < 0.05) accelerated rate of peak force decline during the initial period of stimulation (0.02 + 0.02, 0.03 +/- 0.01, and 0.09 +/- 0.01%/pulse for normal, mild myasthenic, and severe myasthenic, respectively, during continuous stimulation) and intratrain fatigue (up to 30.5 +/- 7.4% intratrain force drop in severe myasthenic vs. none in normal and mild myasthenic, P < 0.01). Furthermore, compared with continuous stimulation, intermittent stimulation had a protective effect on force of severe myasthenic diaphragm (force after 2,000 pulses was 31.4 +/- 2.0% of initial during intermittent stimulation vs. 13.0 +/- 2.1% of initial during continuous stimulation, P < 0.01) but not on normal diaphragm. These data indicate that baseline force and fatigue may be affected to different extents by varying severity of myasthenia gravis and furthermore provide a mechanism by which alterations in breathing pattern may worsen respiratory muscle function in neuromuscular diseases.

Animals↗
PubMed2004

Complement regulators in extraocular muscle and experimental autoimmune myasthenia gravis.

Complement activation at motor endplates is the primary effector mechanism in myasthenia gravis (MG). In this study, we evaluated whether differences in gene transcript levels and protein expression of cell-surface complement regulators could be a factor in the increased susceptibility of extraocular muscle (EOM) compared to other skeletal muscles to MG. Experimental autoimmune MG (EAMG) was induced in mice by administration of a monoclonal antibody (mAb) directed toward the acetylcholine receptor (AChR). Standard RT-PCR and real-time PCR (qPCR) were used to assess mRNA levels of decay-accelerating factor (DAF), CD59, and complement receptor 1-related gene/protein y (Crry). Gene transcript levels of the alpha- and gamma-subunits of the AChR were also evaluated by qPCR. Protein expression of the three intrinsic complement regulators at the neuromuscular junction was assessed by immunohistochemistry. Under constitutive conditions by RT-PCR, no significant differences were detected, but qPCR, EOM showed lower mRNA levels of all three complement regulators, but higher levels of alpha- and gamma-subunit gene transcripts. With EAMG, significant decreases in mRNA levels of all three complement regulators as well as AChR subunits occurred in EOM, but not in the diaphragm. Immunoreactivity for all three complement regulators was highly concentrated at diaphragm junctions, whereas it was less intense or absent at EOM junctions. With EAMG, immunoreactivity for Crry and DAF increased at diaphragm junctions and for DAF at EOM junctions. Diminished intrinsic complement regulatory activity may contribute to the susceptibility of EOM to MG. Our findings suggest that complement inhibitor-based therapies could be useful in treating ocular manifestations of MG.

Animals↗
PubMed2004

Pathophysiology of myasthenia gravis.

Myasthenia gravis (MG) is arguably the best understood autoimmune disease, and its study has also led to fundamental appreciation of mechanisms of neuromuscular transmission. MG is caused by antibodies against the acetylcholine receptor (AChR), which produce a compromise in the end-plate potential, reducing the safety factor for effective synaptic transmission. It is clear that AChR antibody destruction of the postsynaptic surface is dependent on complement activation. A muscle-specific kinase has been recently found to be an antigenic target in MG patients without antibodies against the AChR. Autoantibody production in MG is a T-cell-dependent process, but how a breakdown in tolerance occurs is not known. In MG there is an interesting differential involvement of muscle groups, in particular, the extraocular muscles. This article reviews normal neuromuscular transmission, mechanisms of the autoimmune process of MG, and differential susceptibility of eye muscles to MG.

Autoantibodies↗
PubMed2003

Constitutive properties, not molecular adaptations, mediate extraocular muscle sparing in dystrophic mdx mice.

Extraocular muscle (EOM) is spared in Duchenne muscular dystrophy. Here, we tested putative EOM sparing mechanisms predicted from existing dystrophinopathy models. Data show that mdx mouse EOM contains dystrophin-glycoprotein complex (DGC)-competent and DGC-deficient myofibers distributed in a fiber type-specific pattern. Up-regulation of a dystrophin homologue, utrophin, mediates selective DGC retention. Counter to the DGC mechanical hypothesis, an intact DGC is not a precondition for EOM sarcolemmal integrity, and active adaptation at the level of calcium homeostasis is not mechanistic in protection. A partial, fiber type-specific retention of antiischemic nitric oxide to vascular smooth muscle signaling is not a factor in EOM sparing, because mice deficient in dystrophin and alpha-syntrophin, which localizes neuronal nitric oxide synthase to the sarcolemma, have normal EOMs. Moreover, an alternative transmembrane protein, alpha7beta1 integrin, does not appear to substitute for the DGC in EOM. Finally, genomewide expression profiling showed that EOM does not actively adapt to dystrophinopathy but identified candidate genes for the constitutive protection of mdx EOM. Taken together, data emphasize the conditional nature of dystrophinopathy and the potential importance of nonmechanical DGC roles and support the hypothesis that broad, constitutive structural cell signaling, and/or biochemical differences between EOM and other skeletal muscles are determinants of differential disease responsiveness.

Adaptation, Physiological↗
PubMed2003

Persistent over-expression of specific CC class chemokines correlates with macrophage and T-cell recruitment in mdx skeletal muscle.

Prior studies and the efficacy of immunotherapies provide evidence that inflammation is mechanistic in pathogenesis of Duchenne muscular dystrophy. To identify putative pro-inflammatory mechanisms, we evaluated chemokine gene/protein expression patterns in skeletal muscle of mdx mice. By DNA microarray, reverse transcription-polymerase chain reaction, quantitative polymerase chain reaction, and immunoblotting, convergent evidence established the induction of six distinct CC class chemokine ligands in adult MDX: CCL2/MCP-1, CCL5/RANTES, CCL6/mu C10, CCL7/MCP-3, CCL8/MCP-2, and CCL9/MIP-1gamma. CCL receptors, CCR2, CCR1, and CCR5, also showed increased expression in mdx muscle. CCL2 and CCL6 were localized to both monocular cells and muscle fibers, suggesting that dystrophic muscle may contribute toward chemotaxis. Temporal patterns of CCL2 and CCL6 showed early induction and maintained expression in mdx limb muscle. These data raise the possibility that chemokine signaling pathways coordinate a spatially and temporally discrete immune response that may contribute toward muscular dystrophy. The chemokine pro-inflammatory pathways described here in mdx may represent new targets for treatment of Duchenne muscular dystrophy.

Animals↗
PubMed2003

Molecular organization of the extraocular muscle neuromuscular junction: partial conservation of and divergence from the skeletal muscle prototype.

PURPOSE: The phenotypically novel extraocular muscles (EOMs) exhibit fundamental differences in innervation and neuromuscular junction (NMJ) morphology from other skeletal muscles. In the current study, the morphology and molecular organization of NMJs of EOM singly innervated (SIF) and multiply innervated (MIF) fiber types were evaluated and the distribution of molecules involved in formation and maintenance of NMJs were specifically characterized. METHODS: Adult mouse EOM NMJ organization was examined by immunofluorescence and confocal microscopy. Differential cellular localization of components of two established synaptic signaling pathways, (1) neuregulin and erbB receptors 2, 3, and 4 and (2) agrin, MuSK, and rapsyn and select NMJ-associated structural proteins were studied for EOM SIF and MIF populations. Endplate topography and structure were also studied, using both confocal microscopy and transmission electron microscopy, with NMJ morphologic organization correlated with specific EOM fiber types. RESULTS: Confocal fluorescence microscopy demonstrated that, for NMJs of both EOM SIFs and MIFs, components of neuregulin and agrin pathways and the major components of the junctional dystrophin-glycoprotein complex (DGC) colocalized with acetylcholine receptor (AChR) aggregates. However, EOM exhibited novel fiber-type-specific extrasynaptic localization of two key DGC signaling-related molecules: alpha-dystrobrevin 1 (global MIFs) and syntrophin beta1 (global MIFs and orbital MIFs and SIFs). CONCLUSIONS: The data establish that the molecular organization of EOM SIF and MIF NMJs includes the same signaling and structural molecules previously characterized for other skeletal muscles. By contrast, divergence in other aspects of the synaptic and nonsynaptic sarcolemmal organization of EOM fiber types may underlie the unique responses of these muscles in a variety of neuromuscular disorders.

Animals↗
PubMed2003

Susceptibility of ocular tissues to autoimmune diseases.

The orbital tissues may form a unique immunological environment, as evidenced by autoimmune disorders that specifically target orbital tissues, particularly myasthenia gravis (MG) and Graves' ophthalmopathy (GO). The reasons for the preferential susceptibility are likely to be multiple, based on the interplay of molecular and physiological properties of extraocular muscles (EOM), the unique requirements of the ocular motor system, and the specific autoimmune pathology. Of general importance, even a minor loss of EOM force generation will sufficiently misalign the visual axes to produce dramatic symptoms, and proprioceptive feedback is limited to overcome such a deficit. Particular to MG, EOM synapses appear susceptible to neuromuscular blockade, the autoimmune pathology differs between ocular and generalized MG patients, and the influence of complement regulatory factors may be less prominent in preventing damage at EOM neuromuscular junctions. GO pathogenesis is poorly understood, but shared epitopes of orbital fibroblasts, EOM, and thyroid could lead to specific autoimmune targeting of these tissues. The differential response of orbital fibroblasts to cytokines may be a key factor in disease development. Greater appreciation of the immunologic environment of orbital tissues may lead to therapies specifically designed for orbital autoimmune diseases.

Animals↗
PubMed2003

Development of a thymectomy trial in nonthymomatous myasthenia gravis patients receiving immunosuppressive therapy.

Thymectomy has been regularly used in the management of nonthymomatous autoimmune myasthenia gravis (MG), but its benefits have not been established in a randomized, controlled trial. The widespread use of thymectomy in MG patients without thymoma is largely based on retrospective, nonrandomized case series that have produced a consensus that the procedure is sometimes beneficial. Still, the benefits and utilization of thymectomy are actively debated among MG experts. In this paper, we describe the development of a multicenter, international trial to determine whether extended transsternal thymectomy reduces corticosteroid requirements for patients with generalized AChR antibody-positive nonthymomatous MG.

Adolescent↗